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Effects of Nicotine on Responding Maintained by Environmental Stimuli in Rats

Permanent Link: http://ufdc.ufl.edu/UFE0022040/00001

Material Information

Title: Effects of Nicotine on Responding Maintained by Environmental Stimuli in Rats
Physical Description: 1 online resource (102 p.)
Language: english
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: conditioned, establishing, extinction, food, lights, nicotine, observing, rats, reinforcement, resistance, stimuli
Psychology -- Dissertations, Academic -- UF
Genre: Psychology thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Past research suggests that nicotine-induced increases in reinforced responding are due to its reinforcer-enhancing effects. It is unclear whether this role is specific to certain kinds of reinforcing consequences (e.g., sensory stimuli, edible reinforcers, drug reinforcers). Furthermore, it is possible that nicotine merely increases behavior that has been trained in the past (i.e., responding reinforced with food consequences). The objectives of Experiments 1 and 2 were to test the generality of the motivating establishing operation (MEO) account of nicotine-induced increases in reinforced responding and to determine whether the history of training (responses that have previously been reinforced with food versus those that have not) would augment the effects. Experiment 1 used an observing response procedure to investigate responding maintained by food reinforcers, conditioned reinforcers (i.e., visual stimuli), and responding during extinction. Rats in Experiment 1 received pre-session subcutaneous injections of vehicle (n = 5), 0.3 (n = 6) or 0.56 (n = 6) mg/kg nicotine for 70 sessions. Resistance to extinction was also assessed by removing food for five sessions. Nicotine did not consistently affect food or extinction responding. Both doses of nicotine produced increases in responding maintained by conditioned reinforcers, but did not increase resistance to extinction. Pre-drug response rates accounted for a small but significant percentage of the variance in the drug effect. In Experiment 1, contingent houselight presentations alone were shown to slightly increase response rates from operant levels. Experiment 2 further evaluated the putative primary reinforcing functions of turning on and turning off a houselight. One group of rats (n=4) was initially trained to press both levers (one was later designated as the active lever and the other the inactive lever), while a different group of rats (n =4) was only trained to press the lever that was later designated as the active lever. Across two phases, five responses on the active lever resulted in the houselight either turning on (Lights On) or turning off (Lights Off). All subjects made more responses on the active lever, regardless of lever training history and the type of stimulus change, suggesting that both stimuli served as primary reinforcers. Nicotine only increased responding on the active lever, again regardless of lever training history, which further supported the MEO role, and refuted the alternative hypothesis that nicotine generally increases behavior that has been trained. Although there was a tendency for nicotine to increase low pre-drug response rates in both experiments, nicotine systematically increased responding maintained by conditioned reinforcers in Experiment 1, and only increased responding on an active lever in Experiment 2. The results of both experiments are in accord with the MEO account of nicotine; that it increases responding maintained by moderately reinforcing stimuli, such as the conditioned reinforcers and visual stimuli used in the present studies.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Thesis: Thesis (Ph.D.)--University of Florida, 2008.
Local: Adviser: Dallery, Jesse.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0022040:00001

Permanent Link: http://ufdc.ufl.edu/UFE0022040/00001

Material Information

Title: Effects of Nicotine on Responding Maintained by Environmental Stimuli in Rats
Physical Description: 1 online resource (102 p.)
Language: english
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: conditioned, establishing, extinction, food, lights, nicotine, observing, rats, reinforcement, resistance, stimuli
Psychology -- Dissertations, Academic -- UF
Genre: Psychology thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Past research suggests that nicotine-induced increases in reinforced responding are due to its reinforcer-enhancing effects. It is unclear whether this role is specific to certain kinds of reinforcing consequences (e.g., sensory stimuli, edible reinforcers, drug reinforcers). Furthermore, it is possible that nicotine merely increases behavior that has been trained in the past (i.e., responding reinforced with food consequences). The objectives of Experiments 1 and 2 were to test the generality of the motivating establishing operation (MEO) account of nicotine-induced increases in reinforced responding and to determine whether the history of training (responses that have previously been reinforced with food versus those that have not) would augment the effects. Experiment 1 used an observing response procedure to investigate responding maintained by food reinforcers, conditioned reinforcers (i.e., visual stimuli), and responding during extinction. Rats in Experiment 1 received pre-session subcutaneous injections of vehicle (n = 5), 0.3 (n = 6) or 0.56 (n = 6) mg/kg nicotine for 70 sessions. Resistance to extinction was also assessed by removing food for five sessions. Nicotine did not consistently affect food or extinction responding. Both doses of nicotine produced increases in responding maintained by conditioned reinforcers, but did not increase resistance to extinction. Pre-drug response rates accounted for a small but significant percentage of the variance in the drug effect. In Experiment 1, contingent houselight presentations alone were shown to slightly increase response rates from operant levels. Experiment 2 further evaluated the putative primary reinforcing functions of turning on and turning off a houselight. One group of rats (n=4) was initially trained to press both levers (one was later designated as the active lever and the other the inactive lever), while a different group of rats (n =4) was only trained to press the lever that was later designated as the active lever. Across two phases, five responses on the active lever resulted in the houselight either turning on (Lights On) or turning off (Lights Off). All subjects made more responses on the active lever, regardless of lever training history and the type of stimulus change, suggesting that both stimuli served as primary reinforcers. Nicotine only increased responding on the active lever, again regardless of lever training history, which further supported the MEO role, and refuted the alternative hypothesis that nicotine generally increases behavior that has been trained. Although there was a tendency for nicotine to increase low pre-drug response rates in both experiments, nicotine systematically increased responding maintained by conditioned reinforcers in Experiment 1, and only increased responding on an active lever in Experiment 2. The results of both experiments are in accord with the MEO account of nicotine; that it increases responding maintained by moderately reinforcing stimuli, such as the conditioned reinforcers and visual stimuli used in the present studies.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Thesis: Thesis (Ph.D.)--University of Florida, 2008.
Local: Adviser: Dallery, Jesse.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0022040:00001


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934a689ca01a5d06edcd9a2c1da344983384c3ac







EFFECTS OF NICOTINE ON RESPONDING MAINTAINED BY
ENVIRONMENTAL STIMULI IN RATS




















By

BETHANY R. RAIFF


A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA

2008


































O 2008 Bethany R. Raiff



































To Jack, for providing me with alternative sources of reinforcement.









ACKNOWLEDGMENTS

I thank my mother, Rosanne Gilman, for making me go to college and for being a constant

source of support and I thank my father, Arnold Raiff, for his continuous enthusiasm regarding

my work. I thank my sister, Jennifer Philips, for being a great role model, and I thank my

brother, Elij ah Raiff, for allowing me to be his role model. I thank Matthew Locey for paying the

way. I thank Anthony Defulio, Julie Marusich, and Katie Saulsgiver for being a supportive

cohort; and I thank Steven Meredith and Jeb Jones for helping conduct experimental sessions. I

thank Dr. Gregory Madden for introducing me to behavior analysis and for allowing me to come

into contact with a rich schedule of reinforcement early in my career. I thank Dr. Timothy

Hackenberg for asking me intriguing philosophical questions, giving me the opportunity to learn

new and interesting research techniques in his lab, and for always having an open office door. I

thank Dr. Marc Branch for last minute consultations on issues related to behavioral

pharmacology, and I thank Drs. Neil Rowland and Adriaan Bruijnzeel for providing useful

insights regarding my research. Finally, I thank my advisor, Dr. Jesse Dallery, for constantly

challenging me, always being available for engaging and productive conversations, and for

making many exciting opportunities available to me.












TABLE OF CONTENTS


page


ACKNOWLEDGMENT S .............. ...............4.....


LI ST OF T ABLE S ................. ...............7....__.__.....


LIST OF FIGURES .............. ...............8.....


AB S TRAC T ..... ._ ................. ............_........9


CHAPTER


1 GENERAL INTRODUCTION ........_................. ........_._ .........1


Brief History of Tobacco and Cigarette Smoking in the United States ................. ...............1 1
The Culprit: Nicotine? .............. ...............12....

Drug Self-Administration ................ ...............13.................
Nicotine Self-Administration .............. ...............15....

Motivating Operation Role for Nicotine .............. ...............18....
Alternative Accounts .............. ...............20....

Present Experiments .............. ...............22....


2 EXPERIMENT 1 .............. ...............24....


Introducti on ................. ........... ...............24.......

Conditioning a New Response .............. ...............24....
Observing response .............. ...............26....
Resistance to Extinction .............. ...............28....

Purpose of Experiment 1 .............. ...............29....
M ethod ................. ...............29.................

Subj ects .................. ............ ...............29.......
Apparatus and Materials............... ...............3
Procedure ................. ...............30........._.....
Results ...._.. ................. ........_.._.........36
Discussion............... ...............4


3 Experiment 2 ...._ _. ................. ........_.._.........5


Introducti on ...._ _. ................. ........_.._..........5

Purpose of Experiment 2 ................. ...............58........ .....
M ethods .............. ...............59....

Subj ects .................. ............ ...............59.......
Apparatus and Material s............... ...............5
Procedure ................. ...............59........._.....
Results ...._.. ................. ........_.._.........63
Discussion............... ...............6













4 General Discussion .............. ...............80....


Mechanisms of Action ................. ...............80...._.._ .....
Behavioral Mechanisms .............. ...............80....

Neurobiological Mechanisms .........._...._ ......_. ...............85.....
Concluding Remarks .............. ...............87....


LIST OF REFERENCES ..........._.._._ ...............88..._..._.....


BIOGRAPHICAL SKETCH ..........._.._._ ...............101......_ .....










LIST OF TABLES
Table page


Table 2-1. Hypothetical effects of nicotine on responding maintained by each of the
response types investigated with the observing response procedure ............. ..............45

Table 2-2. Mean + SEM DI, Observing res onse rate, food-extinction res onse rates in the
presence of the S+ and S- from the five sessions prior to the Drug Administration
condition .............. ...............46....

Table 2-3. Mean + SEM response rates just prior to and during the Drug Administration
condition for food-extinction response rates in the presence of the S+ and S-, and for
observing responses .............. ...............47....

Table 2-4. Fitted parameter values and corresponding r2 for each linear regression applied to
the rate-dependent graphs shown in Figure 2-8. ............. ...............48.....

Table 3-1. Proportion of responses on the active lever. ................ ................. ..............71

Table 3-2. Proportion of stimulus presentations during which a response was made ...................72

Table 3-3. Fitted parameter values and corresponding r2 for each linear regression applied to
the rate-dependent graphs shown in Figure 3-6. .............. ...............73....











LIST OF FIGURES
Fiare page

Figure 2-1. Experiment 1 Schematic. ............. ...............49.....

Figure 2-2. Pretests.. ............ ...............50.....

Figure 2-3. Mean (+SEM) Food-Extinction S+, S- and Observing Responses............._..._.. .........51

Figure 2-4. Individual Subject Data Showing Food-Extinction Responses on the S+. ........._......52

Figure 2-5. Individual Subj ect Data Showing Food-Extinction Responses on the S-. ................. .53

Figure 2-6. Individual Subj ect Data Showing Observing Responses. ........._..._.. ....._..._... ......54

Figure 2-7. Resistance to Extinction. ........._.._.. ...._... ...............55...

Figure 2-8. Rate-Dependent Scatterplots. .............. ...............56....

Figure 3-1.Total Responses During Lights On. ............ ...............74.....

Figure 3-2. Total Responses During Lights Off ............. ...............75.....

Figure 3-3. Cumulative Response Records During Lights On.. ............ ........ .............7

Figure 3-4. Cumulative Response Records During Lights Off .............. ...............77...

Figure 3-5. Within-SessionTime Course Analyses............... ...............78

Figure 3-6. Rate-Dependent Scatterplots. ............. ...............79.....









Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy

EFFECTS OF NICOTINE ON RESPONDING MAINTAINED BY
ENVIRONMENTAL STIMULI IN RATS
By

Bethany R. Raiff

May 2008

Chair: Jesse Dallery
Major: Psychology

Past research suggests that nicotine-induced increases in reinforced responding are due to

its reinforcer-enhancing effects. It is unclear whether this role is specific to certain kinds of

reinforcing consequences (e.g., sensory stimuli, edible reinforcers, drug reinforcers).

Furthermore, it is possible that nicotine merely increases behavior that has been trained in the

past (i.e., responding reinforced with food consequences). The objectives of Experiments 1 and 2

were to test the generality of the motivating establishing operation (MEO) account of nicotine-

induced increases in reinforced responding and to determine whether the history of training

(responses that have previously been reinforced with food versus those that have not) would

augment the effects.

Experiment 1 used an observing-response procedure to investigate responding maintained

by food reinforcers, conditioned reinforcers (i.e., visual stimuli), and responding during

extinction. Rats in Experiment 1 received pre-session subcutaneous inj sections of vehicle (n = 5),

0.3 (n = 6) or 0.56 (n = 6) mg/kg nicotine for 70 sessions. Resistance to extinction was also

assessed by removing food for five sessions. Nicotine did not consistently affect food or

extinction responding. Both doses of nicotine produced increases in responding maintained by









conditioned reinforcers, but did not increase resistance to extinction. Pre-drug response rates

accounted for a small but significant percentage of the variance in the drug effect.

In Experiment 1, contingent houselight presentations alone were shown to slightly

increase response rates from operant levels. Experiment 2 further evaluated the putative primary

reinforcing functions of turning on and turning off a houselight. One group of rats (n=4) was

initially trained to press both levers (one was later designated as the active lever and the other the

inactive lever), while a different group of rats (n =4) was only trained to press the lever that was

later designated as the active lever. Across two phases, five responses on the active lever resulted

in the houselight either turning on (Lights On) or turning off (Lights Off). All subj ects made

more responses on the active lever, regardless of lever training history and the type of stimulus

change, suggesting that both stimuli served as primary reinforcers. Nicotine only increased

responding on the active lever, again regardless of lever training history, which further supported

the IVEO role, and refuted the alternative hypothesis that nicotine generally increases behavior

that has been trained.

Although there was a tendency for nicotine to increase low pre-drug response rates in

both experiments, nicotine systematically increased responding maintained by conditioned

reinforcers in Experiment 1, and only increased responding on an active lever in Experiment 2.

The results of both experiments are in accord with the IVEO account of nicotine that it

increases responding maintained by moderately reinforcing stimuli, such as the conditioned

reinforcers and visual stimuli used in the present studies.









CHAPTER 1
GENERAL INTRODUCTION

Brief History of Tobacco and Cigarette Smoking in the United States

Tobacco use by humans dates back centuries, ranging from religious, recreational and at

times even medicinal uses. Columbus and his crew first introduced tobacco to Spain after

visiting the Americas in 1492 and seeing a number of indigenous North Americans "drinking the

smoke" (Gold, 1995). At the time, many North Americans considered tobacco sacred and in

some cases medicinal (Hatch, 1942; Kluger, 1997). Although tobacco was initially used by

Europeans for recreational purposes, from the 1600s until the mid 1800s it was considered the

"panacea of panaceas" in both Europe and the United States, being prescribed to treat various

ailments such as asthma, nasal congestion, thirst, wounds, teeth whitening, and even the bubonic

plague (Stewart, 1967). Eventually physicians became skeptical of the substance because of

nicotine's apparent "addictive" properties, and by around 1860 tobacco was no longer being

prescribed for medicinal purposes (Stewart, 1967). Nevertheless, it was not long after, around

1880, when the first cigarette-rolling machines were invented, which led to the mass production

and sales of cigarettes for predominantly recreational purposes (Gold, 1995).

With increasing sales came increasing economic interest in tobacco in the United States.

The New Tobacco Company was formed in 1889 and 10 years later RJ Reynolds, the makers of

well known Camel cigarettes, was incorporated. In 1902 Philip Morris and Company, makers of

Marlboro cigarettes, came to New York (Kluger, 1997), and today Philip Morris claims more

than 50% of the U.S. tobacco market (Cooper, 2004). In the U.S alone, over 100,000 hectares of

land are devoted to growing tobacco, with most of the farms located in North Carolina (Food and

Agricultural Organization, 2003; Gold, 2005).









In 1964, the U.S. Surgeon General's report formally stated that there was a relationship

between smoking and cancer and the Federal Cigarette Labeling and Advertising Act of 1965

required that all tobacco products bear a warning label (Centers for Disease Control and

Prevention [CDC], 2006). Since 1965, the percentage of current smokers has declined from

about 42%, remaining at an estimated 24% of the U.S. adult population since 2003 (CDC, 2006).

In addition to cancer, smoking has been associated with a number of other health problems, such

as emphysema, coronary heart disease, and stroke, with approximately 440,000 deaths attributed

to smoking-related illnesses each year (CDC, 2005). Although about 70% of smokers report a

desire to quit (CDC, 2005), approximately 60-90% of those who attempt to quit end up relapsing

within one year (Carmody, 1992). Cigarette smoking is currently a primary public health concern

in the United States. Despite this long history of tobacco use in the United States, the question

remains: what has made tobacco such a successful commodity?

The Culprit: Nicotine?

The answers, of course, are complex. Each year tobacco companies spend over $15

billion dollars on advertising almost $50 million per day (Federal Trade Commission, 2005).

Indeed, advertisements have been shown to influence adolescents' self-reported intentions to

smoke cigarettes (Straub, Hills, Thompson, Moscicki, 2003) and smoking initiation (Pierce,

Choi, Gilpin, Farkas, Berry, 1998).

In addition to social and cultural influences on smoking, the pharmacological effects of

nicotine have been implicated in the success of tobacco products. Of the approximately 4,000

constituents found in tobacco, the primary psychoactive ingredient is nicotine, which was first

extracted from tobacco in 1828 (Henningfield & Zeller, 2006). The effects of nicotine on the

central nervous system are similar to the effects of other drugs of abuse, such as cocaine, heroin,

and amphetamine, in that they all affect the mesolimbic dopamine system (McKim, 1997; Pierce









& Kumaresan, 2006; Wonnacott, Sidhpura, Balfour, 2005). Each drug affects the area in a

slightly different way, but they all result in dopamine release, either directly or indirectly.

Research suggests that it is particularly important that the drug result in increased dopamine

activity in the ventral tegmental area and the nucleus accumbens, which nicotine does both

directly by stimulating dopamine neurons and indirectly by initiating glutamate release (Pierce &

Kumaresan, 2006). Because these effects on the mesolimbic dompamine system appear to be

critical to the reinforcing effects of most other drugs of abuse, the fact that nicotine also has these

effects suggests that its presence in tobacco products might be responsible for the high rates of

tobacco use (Stolerman & Jarvis, 1995; Stolerman, 1999). Behavioral pharmacologists have been

particularly interested in determining whether nicotine is responsible for smoking maintenance

and relapse, and have used the self-administration procedure to explore this possibility.

Drug Self-Administration

The discipline of behavioral pharmacology combines the principles of pharmacology

with the principles of behavior analysis (Poling & Byrne, 2000; Thompson & Schuster, 1968).

Behavior analysis uses a natural science approach to understanding the behavior of organisms,

and places an emphasis on environmental variables (Cooper, Heron, Heward, 2007; Skinner,

1953). Operant behavior, in contrast with respondent behavior, is defined as behavior whose

future likelihood is affected by its consequences, and it comprises most of the behavior of

humans (Cooper, Heron, Heward, 2007; Skinner, 1953). Although there are many facets of both

operant and respondent conditioning that are of interest to behavioral pharmacologists, one area

that has generated interest is reinforcement. Reinforcement is the process by which a response

occurs, a stimulus event follows, and the result is an increase or maintenance in the future

probability of the response (Poling & Byrne, 2000; Skinner, 1953; Thompson & Schuster, 1968).

Behavioral pharmacologists have extended the concept of reinforcement by conceptualizing










drugs as potential reinforcers and drug seeking and use as operant behavior (Carlton, 1983;

McKim, 1997; Poling & Byrne, 2000). For human smokers, these behaviors might include going

to the store to buy cigarettes, asking another smoker for a cigarette, inhaling the smoke, etc., with

nicotine as the key ingredient thought to be involved in the reinforcing function of the cigarettes.

Drug self-administration procedures were developed by behavioral pharmacologists for

use with nonhuman subj ects under controlled laboratory conditions (Carlton, 1983; Haney &

Spealman, 2008), and are considered analogous to human drug use and drug seeking. Self-

administration procedures are often conducted in operant chambers whereby the drug is

delivered (usually intravenously through a catheter) after a response is made (e.g., a lever press

with rats or non-human primates; Thompson & Schuster, 1964). For example, the lever press

that results in a nicotine infusion would be considered functionally equivalent to a smoker lifting

a cigarette to one's mouth and inhaling nicotine. Early self-administration studies demonstrated

that nonhumans would self-administer drugs such as morphine and cocaine on various schedules

of reinforcement (Thompson & Schuster, 1964; Pickens & Thompson, 1968). Thompson and

Schuster (1968) demonstrated that the patterns of responding maintained by morphine were

similar to the patterns of responding maintained by food, and that morphine deprivation had

similar effects as food deprivation on those response patterns. These findings provided empirical

support for the notion that drugs could produce effects that were similar to other reinforcing

consequences.

One method that has also been used to further investigate the reinforcing function of a

drug involves delivering an agonist or antagonist of the drug, either before the session or

noncontingent on responding during the session, and determining self-administration of the drug

itself is influenced. For example, in one study baboons were given a choice between earning









food and self-administering heroin. Subj ects chose to self-administer heroin on approximately

half of the trials. When noncontingent morphine, an opioid agonist, was added to the session the

number of heroin choices decreased. In this case, morphine could be considered a substitute for

heroin, which led subj ects to allocate their choices to food instead of heroin. Similar changes in

choice allocation were seen when naloxone (an opioid antagonist) was given, suggesting that it

blocked the reinforcing effects of heroin (Griffiths, Wurster, Brady, 1981).

Nicotine Self-Administration

It has long been argued that the widespread use of tobacco products can be attributed, in

part, to nicotine's primary reinforcing properties (Russell, 1971; Stolerman & Jarvis, 1995).

However, unlike most other drugs of abuse, it has been very difficult to establish nicotine self-

administration in nonhumans. Eventually, in 1989, Corrigal and Coen (1989) published a study

that seemed to convincingly demonstrate nicotine self-administration in laboratory rats. The

procedure involved several features that now seem to be important for generating nicotine self-

administration. The rat was food-deprived and then trained to press one of two levers. Food was

used as the consequence. When lever pressing was established, food was replaced with nicotine

for pressing the previously trained lever, and the other lever was designated inactive. Eventually

an intermittent (fixed ratio [FR]) schedule was introduced, whereby a fixed number of responses

were required for each infusion. Each nicotine infusion was paired with the brief onset of a

stimulus light above the active lever, followed by a 60 s time out, during which all visual stimuli,

including the houselight, were turned off. Sessions were 1 hr in duration and the entire

experiment lasted for a few weeks to one month, but rarely longer. Since the publication of this

procedure in 1989, it has been the predominant method used to study nicotine self-administration

(e.g., Cohen, Perrualt, Griebel, Soubrie, 2005; Corrigal & Coen, 1989; Caggiula et al., 2001,

2002a,b; Chaudhri et al., 2006a; Donny et al., 2003). Variations of this procedure sometimes









involve more extended access to nicotine (e.g., 23 hr / day), the use of nonhuman primate

subj ects, and in some cases omitting the food deprivation and lever training protocols (Denoble

& Mele, 2006; Goldberg, Spealman, Goldberg, 1981; Harris, Burroughs, Pentel, Lasage, 2008;

Valentine, Hokanson, Matta, Sharp, 1997). It should be noted, however, that in all of the

procedures just cited, some form of stimulus change always accompanied the nicotine infusions.

In fact, the stimulus change accompanying each nicotine infusion appears to play a

critical role in nicotine self-administration with nonhumans. Caggiula and colleagues have

conducted a number of experiments demonstrating that when the stimulus change is removed,

nicotine self-administration decreases to levels that are almost indistinguishable from vehicle

self-administration (Caggiula, et al., 2001; Caggiula, Donny, Chaudhri, Perkins, Evans-Martin,

Sved, 2002a; Caggiula et al., 2002b; Chaudhri et al., 2005). Caggiula and colleagues (2002b)

conducted a systematic investigation into the features of the stimulus change (e.g., turning on a

houselight, turning on a light above the lever, turning off a houselight, or turning on a brief lever

light and tone). The authors found that turning off a houselight maintained more responding than

the other stimuli, and that adding contingent nicotine increased responding maintained by turning

off the houselight to a greater extent than the other stimulus changes investigated. Furthermore,

when nicotine was removed, but turning off the houselight continued to be presented contingent

on a FR 5 schedule of lever pressing, responding decreased substantially (Caggiula et al., 2001).

This finding led the researchers to conclude that nicotine did in fact function as a primary

reinforcer, albeit a weak one.

Although it is possible that nicotine serves as a weak primary reinforcer, it is also

possible that the mere presence of nicotine has behavioral effects that make it appear to function

as a reinforcer (Branch, 2006). One technique that has been employed to distinguish between the









reinforcing effects of a stimulus, as opposed to its eliciting or discriminative effects, is to deliver

the sti mulu s re spon se -indep endently (Pi cken s & Thomp son, 1 96 8; S izem ore & Lattal, 1 9 77).

Donny and colleagues (Donny et al., 2003) did just that by exposing one group of rats to the

traditional self-administration paradigm described above and yoking the nicotine infusions

earned by this group to a different group of rats who only earned stimulus changes contingent on

lever pressing. Interestingly, the group of rats who received yoked nicotine infusions responded

almost as much on the stimulus change lever as the group who earned contingent nicotine plus

contingent stimulus changes. To rule out adventitious reinforcement in the yoked group, a

second study was conducted that involved one continuous infusion of nicotine during each

session, along with response contingent stimulus changes. As in the yoked experiment, the mere

presence of nicotine resulted in increases in responses maintained by the visual stimulus change.

A number of other studies have been conducted to further corroborate the finding that nicotine

increases responding maintained by stimulus changes (Chaudhri et al., 2006; Olausson, Jentsch,

& Taylor, 2004a, b; Palmatier et al., 2006, 2007; Raiff & Dallery, 2006).

In addition to increasing responses maintained by moderately reinforcing sensory stimuli,

nicotine has also been shown to increase responding maintained by more potent primary

reinforcers, such as cocaine (Bechtholt & Mark, 2002; McQuown, Belluzi, Leslie, 2007), alcohol

(Clark, Lindgren, Brooks, Watson, Little, 2001; L6, Wang, Harding, Juzytsch, Shaham, 2003;

Smith, Horan, Gaskin, Amit, 1999) and sucrose dissolved in water (Jias & Ellison, 1990).

Despite these "direct" pharmacological effects of nicotine on responding, many researchers

maintain the position that nicotine serves as a primary reinforcer (e.g., Chaudhri et al., 2006; Le

Foll, Wertheim, Goldberg, 2007). Thus, there are at least two roles for nicotine: (1) nicotine

functions as a primary reinforcer that can maintain responding in the absence of visual stimuli









and can establish neutral stimuli as conditioned reinforcers and (2) nicotine can enhance the

reinforcing efficacy of other reinforcers when delivered contingent or noncontingent on a

response (Chaudhri et al., 2006). The viability of the first role is beyond the scope of this paper --

instead the hypothesis that nicotine acts as a reinforcer-enhancer will be explored in the section

that follows.

Motivating Operation Role for Nicotine

In behavior analysis, the concept of motivating operations is critically important to the

concept of reinforcement in general. A motivating operation (MO) is an antecedent event that (1)

temporarily alters the efficacy of certain consequences (reinforcer value-altering), and (2)

changes the likelihood of responses that have resulted in that consequence in the past (response-

altering; Laraway, Snycerski, Michael; Michael, 1982; Michael, 1993; Michael, 2000). MOs can

either work by increasing or decreasing the efficacy of certain consequences, and thus increasing

or decreasing the future probability of a response, respectively. The former is often referred to as

an establishing operation, the latter an abolishing operation (Michael, 1982). For example, food

deprivation is an establishing operation because it temporarily increases the reinforcing value of

food, and thus increases the likelihood of responses that have previously resulted in receipt of

food. Alternatively, food satiation is an abolishing operation and thus decreases the likelihood of

responses which have led to the receipt of food in the past. For the purposes of this discussion,

only those antecedent events that increase the future likelihood of a response will be discussed

and they will be summarized by the term motivating establishing operation (MEO).


The concept of the MEO has been fruitful and practical in applied behavior analysis

(Dicesare, McAdam, Toner, Varrell, 2005; Iwata, Dorsey, Slifer, Bauman, Richman, 1994;

Iwata, Smith, Michael, 2000; McAdam et al, 2005; McComas, Hoch, Paone, El-Roy, 2000;









Northup, Fusilier, Swanson, Roane, Borrero, 1997). Although the principles of reinforcement,

punishment, and stimulus control have been widely applied to behavioral pharmacology research

(Branch, 2006; Carlton, 1983; Thompson & Schuster, 1968) the concept of the MEO has been

neglected. Only two known studies directly applied the concept of MOs to drug effects

(Dicesare, McAdam, Toner, Varrell, 2005; Northup, Fusilier, Swanson, Roane, Borrero, 1997).

One study found that the disruptive behavior of an individual with attention deficit hyperactivity

disorder (ADHD) was reinforced by therapist attention, but only in the absence, and not the

presence, of methylphenidate treatment (Dicesare, McAdam, Toner, Varrell, 2005). This is an

example of how the drug served as an abolishing operation (i.e., it decreased the reinforcing

efficacy of attention). Another study found that methylphenidate increased the relative

reinforcing efficacy of some classroom activities for a child with ADHD, while it decreased the

relative reinforcing efficacy of edible items for the same child, suggesting that the drug could

function as an establishing operation in some cases and an abolishing operation in others.


Both of the studies just described were conducted by applied behavior analysts and

published in the Journal ofApplied Behavior Analysis. Thus, the application of MOs to the more

general behavioral pharmacology community was not made. Indeed, nicotine's reinforcer-

enhancing effects are consistent with a MEO account. If nicotine does in fact serve as a MEO, it

should increase the value of some reinforcers, and increase the likelihood of responses which

have led to the receipt of those reinforcers in the past. Conceptualizing nicotine as a MEO

provides a unifying behavioral mechanism of action. Furthermore, investigating the MO role of

drugs could be fruitful, both conceptually and empirically, in behavioral pharmacology in

general (Poling & Byrne, 2000; Thompson, 2007).









Alternative Accounts

In pursuing the putative IVEO role of nicotine, alternative explanations regarding how

nicotine might affect behavior must also be considered. The following sections discuss the

potential rate-dependent effects of nicotine, and the possibility that nicotine merely increases

behavior.

Rate Dependence. One of the most well-known and influential phenomenon in

behavioral pharmacology is rate dependence. In 1955, Dews conducted an experiment showing

that pentobarbital could have opposite effects on behavior, depending on the schedule of

reinforcement maintaining the response (ratio or interval) the same dose decreased responding

on an interval schedule and increased responding on a ratio schedule. This finding was

perplexing at the time because it contradicted the notion that some drugs are stimulants and

always increase behavior while other drugs are depressants and always decrease behavior.

Consequently, behavioral pharmacologists began placing greater emphasis on environmental

variables due to their clear interaction with drug effects (Branch, 1984).

Since Dews' initial finding, it has been demonstrated repeatedly that baseline, pre-drug,

rates of responding are related to the direction of a drug' s effect on responding. The most

common rate-dependent effects involve increases in low pre-drug response rates and decreases in

high pre-drug response rates. Rate-dependent effects have been demonstrated both within

subj ect and across subjects, and for a number of different drugs, but most often with

amphetamine (Lucki, 1983; Saulsgiver, McClure, Wynne, 2007; Wenger & Dews, 1976). Rate-

dependent effects are typically plotted as a log percentage of pre-drug response rates (i.e.,

drug/pre-drug x 100) as a function of log pre-drug response rates. Linear regression analyses are

then performed on the data, revealing a negative slope if rate-dependent effects exist, such that










low pre-drug rates increase and high pre-drug rates decrease (Branch, 1984; Poling & Byrd,

2000), and a slope of zero if rate-dependent effects do not exist.

Almost all of the studies that have been used to support the reinforcer-enhancing account

of nicotine have involved low response rates that increase when nicotine is present (Chaudhri et

al., 2006; Olausson, Jentsch, & Taylor, 2004a, b; Palmatier et al., 2006, 2007; Raiff & Dallery,

2006). There are no known studies with laboratory animals that have directly applied rate-

dependent analyses described above to the effects of nicotine. However, Perkins (1999)

conducted a review of research on nicotine and found a few instances that were consistent with

rate-dependent effects (Shaefer & Michael, 1986; Stitzer, Morrison, Domino, 1970; Vale &

Balfour, 1989). For instance, in one study intermediate doses of nicotine did not affect the high

rates of responding maintained by a FR1 schedule of intracranial brain stimulation (ICSS), but

the same doses did increase the lower rates of responding maintained on a FR 15 schedule of

ICSS (Shaefer & Michael, 1986). Due to the relative dearth of research aimed at evaluating rate-

dependent effects with nicotine, and the pervasiveness of the phenomenon with other drugs, the

need for a more systematic investigation is warranted. It is possible that the increases in

responding that occur as a function of nicotine administration can be entirely accounted for

(although not necessarily explained) by pre-drug rates of responding.

General Motoric Effects. Probably the most outspoken about their disagreement with

the conclusion that nicotine serves as a primary reinforcer or a reinforcer-enhancer are Hanan

Frenk and Reuven Dar (Frenk & Dar, 2000, 2004; Dar & Frenk, 2002a, b, 2004, 2005). Frenk

and Dar have suggested that the nicotine-induced increases seen in laboratory animals can be

accounted for by the general locomotor increasing effects of nicotine. Many of the studies used

as evidence of nicotine' s primary and/or reinforcer-enhancing roles have argued against the










general locomotor activity account by explaining that increases in responding only occur on the

active lever, with the inactive lever used as a control for general, undifferentiated increases in

responding (e.g., Chaudhri et al., 2006). Recall that in these experiments subj ects were initially

trained with food to press the active lever only. Frenk and Dar (2004) argued that comparing

active to inactive lever presses was not justified because inactive responses were never

reinforced. In other words, Frenk and Dar believe that only responses that have been trained

should be expected to increase when nicotine is delivered. Furthermore, there are a number of

studies that have demonstrated nicotine's general locomotor increasing effects when studied in

an open field activity chamber (Dwoskin, Crooks, Teng, Green, Bardo, 1999; Faraday, Elliott,

Phillips, Grunberg, 2003; Green, Cain, Thompson, Bardo, 2003; Koehl, Bjijou, Le Moal, Cador,

2000; Kosowski & Liljequist, 2005; Panagis, Nisell, Nomikos, Chergui, Svensson, 1996). Thus,

while evaluating the potential MEO effects of nicotine, it will be necessary to consider the

possibility that nicotine increases activity in general.

Present Experiments

In the sections that follow, two experiments are described that sought to investigate the

MEO account of nicotine-induced increases in responding, while also considering the possible

rate-dependent and general activity increasing effects of the drug. The first experiment evaluated

the generality of the MEO account by studying the effects of nicotine on responding maintained

by sucrose-based food pellets and conditioned reinforcers, as well as investigating the effects of

nicotine on responding during periods of extinction. The second experiment further assessed the

potential primary reinforcing function of the visual stimuli used in Experiment 1 and the visual

stimuli used in nicotine self-administration studies. Furthermore, two groups of rats were given










different lever training histories to determine whether such differences would influence the

effects of nicotine.









CHAPTER 2
EXPERIMENT 1
Introduction

The stimuli associated with nicotine infusions have been conceptualized as conditioned

reinforcers because of their repeated pairings with nicotine (Caggiula et al., 2001) and have been

compared to the stimuli that are associated with nicotine delivered from cigarettes, such as the

smell and taste of smoke (Chaudhri et al., 2006). It has become increasingly clear that the stimuli

associated with cigarettes may contribute to smoking maintenance and relapse (Dallery,

Houtsmuller, Pickworth, & Stitzer, 2003; Dar & Frenk, 2004; Dols, Willems, & van den Hout,

2000; Field & Duka, 2001; Rose, Behm, Westman, & Johnson, 2000; Rose, Tashkin, Ertle,

Zinser, & Lafter, 1985; Westman, Behm, & Rose, 1996). Although a number of procedures have

been used to study conditioned reinforcement (Kelleher & Gollub, 1962; Williams, 1994), the

two procedures most relevant to the current research will be discussed in detail: the

"conditioning a new response" and "observing response" procedures.

Conditioning a New Response

The conditioning a new response procedure was recently used to study self-administered

and experimenter-delivered effects of nicotine on responding maintained by conditioned

reinforcers (Olausson, Jentch, & Taylor, 2004a, b; Chaudhri et al., 2006). This procedure involves

pairing a stimulus (e.g., light & tone) with a primary reinforcer (e.g., water or sucrose). After many

exposures of the light and tone paired with the primary reinforcer, a new response is trained (e.g.,

pressing a lever) by having the response produce the light and tone in the absence of the primary

reinforcer. If the response is acquired, the stimulus is said to be a conditioned reinforcer because

the primary reinforcer was never made contingent on this new response.

When rats were inj ected with nicotine prior to sessions using the conditioning a new

response procedure, they responded more for the conditioned reinforcer than when they were given









vehicle (Olausson et al., 2004a). When a different group of rats were inj ected with nicotine for 15

consecutive days prior to the conditioning a new response procedure they responded more to

produce conditioned reinforcers than rats given vehicle for 15 consecutive days (Olausson et al.,

2004b). These results suggest that nicotine potentiates responding acquired by the putative

conditioned reinforcer when it is delivered during, or prior to, acquisition of a new response this

finding is consistent with the MEO account of nicotine discussed earlier.

Although the conditioning a new response procedure is highly regarded for studying

conditioned reinforcement, it has several limitations compared to other procedures (Fantino, 1977;

Williams, 1994). In the experiments described above, it is not clear whether the light and tone

were actually conditioned reinforcers. The authors never measured responding for these stimuli

prior to pairing them with the primary reinforcer. Some visual stimuli have been shown to serve as

weak primary reinforcers, even without being paired with other primary reinforcers (Goodrick,

1970; Robinson, 1959; Segal, 1959; Stewart, 1960; Tapp, Mathewson, Simpson, 1968). Even if the

stimuli are conditioned reinforcers, another limitation of the procedure is that only a few sessions

can be conducted before responding begins to diminish. This is because during the acquisition of a

new response, pairing between the primary and conditioned reinforcer is broken--that is, the

conditioned reinforcer is placed on extinction because it is no longer associated with primary

reinforcement. One can only observe a few days of responding for conditioned reinforcers before it

becomes less likely and eventually ceases (Williams, 1994). If an effect of nicotine on extinction

were the only question, this method would be sufficient; however, it restricts the generality of the

results because typically nicotine is taken daily over long periods of time in the presence of

conditioned reinforcers. Finally, this procedure only assesses effects of nicotine on putative









conditioned reinforcers, while failing to detect potential effects on other reinforcing consequences

(Donny et al., 2003).

Observing response

The observing-response procedure can be used to study a number of environmental events,

conditioned reinforcement being one of them (Wyckoff, 1952). This procedure has been used to

investigate the conditioned reinforcing properties of drug-associated stimuli; specifically, cocaine

and remifentanil (Woods & Winger, 2002) and ethanol (Shahan, 2003). The observing-response

procedure involves presenting one stimulus (e.g., red light; S+) with periods of food availability

and a different stimulus (e.g., blue light; S-) with periods of extinction (i.e., no food availability).

Typically there is one response that produces food (i.e., food responses), when it is available and a

different response, hereafter the observing response, that briefly turns on the stimulus associated

with the schedule in effect. It should be noted that observing responses are not required for food

deliveries to occur and making observing responses does not have any effect on the probability of

food being delivered.

Over the years there has been controversy regarding why the stimuli in observing response

procedures function as reinforcers. Some have argued that it is because of the conditioned

reinforcing properties of the stimuli (Case & Fantino, 1981; Williams, 1994), while others have

argued that it is because of the information provided by the stimuli (Berlyne, 1957; Hendry, 1969).

Proponents of the information hypothesis argued that observing responses occurred because they

reduced uncertainty about how to respond in a particular situation. The S+ and S- both provide an

equal amount of information regarding how to respond, and thus either stimulus should maintain

observing responses similarly. However, an extensive amount of research has shown that

observing responses are primarily maintained by the stimulus associated with food (S+) and not









extinction (S-; Case & Fantino, 1981; Dinsmoor, 1983; Dinsmoor, Brown, & Lawrence, 1972),

supporting a conditioned reinforcement account.

There are several reasons to prefer the observing response method to other methods of

studying conditioned reinforcement. First, it is possible to examine effects of several different

kinds of responses during all sessions: (1) responses maintained by food, (2) responses that have

never been explicitly reinforced during extinction, and (3) responses maintained by conditioned

reinforcers. Table 2-1 illustrates four hypothetical outcomes regarding the effects of nicotine on

each response type just listed. As Table 2-1 shows, the observing response procedure allows for

the identification of selective increases in responses maintained by primary or conditioned

reinforcers (Outcomes #1 or #2), as well as general increases in responding (Outcome #3) as

proposed by Frenk and Dar (2004).

One possible limitation of the observing response procedure is if increases were to occur on

both the food and observing lever at the same time (Outcome #4). If this were to happen, it would

not be clear whether increases were the result of nicotine' s independent effects on each type of

consequence, or whether increases in observing responses were the indirect result of increases the

value of the back-up primary reinforcer, food. In fact, it has been demonstrated that increases and

decreases in the magnitude of the back-up reinforcer result in increases and decreases in the rate of

observing responses, respectively (Shahan, 2002). The value of the conditioned reinforcer is

necessarily associated with the value of the primary reinforcer. If increases in observing responses

were indirectly related to increases in the value of the primary reinforcer in this example, one

would expect food-maintained responses to increase prior to, or at the same time as, observing

responses. Thus, given that all responses are recorded simultaneously, the observing response










procedure provides a method for isolating the effects of nicotine on different environmental

consequences.

In a recent experiment conducted in our lab, Raiff and Dallery (2006) used an observing

response procedure to investigate the effects of nicotine, and found that intermediate doses of

subcutaneous (s.c.) inj sections of nicotine (i.e., 0. 1, 0.3 and 0.56 mg/kg base) increased observing

responses during acute and chronic nicotine administration. Furthermore, slight increases in

food-maintained responding were found, but only after chronic nicotine administration. This

addresses the concern just described in the previous section, suggesting that the increases in

observing responses were independent of potential changes in the value of food. The findings

from this study were consistent with the hypothesis that nicotine served as a MEO for the

conditioned reinforcers, and it suggests that under some conditions it may even serve as a

motivating operation for a more potent primary reinforcer-- namely, food. However, Raiff and

Dallery (2006) relied solely on rate of responding to infer changes in the value of the reinforcer

(i.e., rate of observing responses increased under some doses of nicotine). Another method that

has been used to infer the relative value of a reinforcer is resistance to extinction (Nevin, 1974).


Resistance to Extinction

The MEO account specifies that responding will increase when the reinforcing stimuli are

available or made contingent on some response. Moreover, if nicotine serves as a MEO by

increasing the value of reinforcers, then subj ects exposed to nicotine should be more resistant to

extinction when reinforcing stimuli are withdrawn. Such a prediction follows from behavioral

momentum theory, which distinguishes between response-reinforcer relations and stimulus-

reinforcer relations (Nevin, 1974). Response-reinforcer relations suggest that the contingencies

of reinforcement are responsible for engendering different response rates. For instance, a variable









ratio schedule will produce a higher rate of responding than a fixed ratio schedule of equal value.

Stimulus-reinforcer relations, on the other hand, suggest that situations with a higher rate or

larger amount of reinforcement will have greater value, which results in greater resistance to

extinction (Nevin & Grace, 2000). A number of studies have corroborated this distinction by

showing that responses maintained by a richer schedule or greater amount of reinforcement will

be more resistant to extinction than responses maintained by a leaner rate or lower amount of

reinforcement, regardless of the rate of responding before extinction (Nevin & Grace, 2000;

Nevin, 1974). Thus, if nicotine increases the value of primary and conditioned reinforcers, then

responding should be more resistant to extinction when nicotine is present compared to when

nicotine is absent.

Purpose of Experiment 1

Experiment 1 sought to: (1) replicate the findings reported by Raiff and Dallery (2006) by

administering different doses of nicotine (0.3 and 0.56 mg/kg the doses that consistently

produced increases in responding) across groups of rats, (2) investigate whether nicotine-induced

changes in responding could be described as rate-dependent, and (3) assess whether the behavior

of rats exposed to nicotine are more resistant to extinction than the behavior of rats exposed to

vehicle.

Method

Subj ects

Subj ects were eighteen naive male Long-Evans rats (Harlan; Indianapolis, IN). The rats

were approximately 150 days old at the beginning of the experiment. They were individually

housed in hanging polycarbonate cages with bedding, in a room that was temperature and

humidity controlled. Subj ects had free access to water and were maintained at approximately

85% of their 150 day old ad libitum weights, via post-session feeding (Lab Diet Rodent Diet,









Formula 5001; PMINutrition International, LLC; Brentwood, MO). The colony room was on a

12:12 hr light dark cycle (lights on from 8am-8 pm).


Apparatus and Materials

Eight Med Associates@ extra tall operant chambers (Model ENV 007; 30.48 cm L x

24.13 cm W x 29.21 cm H) were used to conduct experimental sessions. Chambers were

contained in large sound attenuating boxes equipped with fans for ventilation. Intelligence

panels, sidewalls, grid floors and drop pans were made of stainless steel; back walls, ceilings,

and doors were made of clear polycarbonate. Each intelligence panel contained a food receptacle

(5 cm x 5 cm x 3 cm) that was equidistant between two levers (requiring approximately 0.31 N

force), each of which measured 4.5 cm x 2 cm and were located 22 cm from the chamber ceiling.

Seven cm above each lever were three light-emitting diodes (LED; red, yellow, green; 0.8 cm in

diameter, 0.7 cm apart from each other). On the wall parallel to the intelligence panel was a

house light (28 volt), centered left to right and 1.5 cm from the ceiling. Purified Rodent Tablets

(45 mg sucrose food pellets; TestDiet", Richmand, IN) were located outside of the chamber, but

inside of the sound attenuating box in a circular pellet dispenser (Model ENV-203). A white

noise generator was in the experimental room to mask extraneous sounds. Experimental events

and data collection took place on a computer in the same room, using Med-PC software and

hardware (MED Associates). On drug delivery days, nicotine ([-]-Nicotine Hydrogen Tartrate

Salt; Sigma, St. Louis, MO), dissolved in a potassium phosphate buffered saline, was used.

Procedure

All sessions were conducted on separate days, seven days per week, at approximately the

same time during the light cycle each day. A 10 min blackout period preceded each session,

during which lever presses did not have any programmed consequences, but were recorded. The










pre-session blackout period was implemented to allow for nicotine absorption in subj ects

receiving nicotine during the Drug Administration condition (described in more detail below).

Figure 2-1 shows a schematic of the progression of conditions that are described in the sections

that follow.

Pre-tests. All pre-test conditions were conducted before subj ects had experience earning

food for pressing levers. The first pre-test was intended to evaluate the operantt level" of

responding in the presence of the stimuli that were to be used later in the observing response

procedure. Hereafter, this condition will be referred to as the "Operant Evaluation" condition.

After the blackout period, the houselight was illuminated for 10 additional minutes. The

houselight was either blinking (0.3 sec on, 0.3 sec off) or continuously illuminated, alternating

every 2 min between the two stimulus types. Lever presses during this 10 min period did not

have programmed consequences but were recorded. Operant Evaluation tests were conducted for

two consecutive sessions.

Next, responding was evaluated when the consequence for pressing the levers consisted

of turning on a blinking or continuous houselight. Hereafter, this condition will be referred to as

the "Stimulus Evaluation" condition. After the blackout, the session lasted for 10 min during

which one lever was designated as the blink lever and the other lever was designated as the

continuous lever (counterbalanced across subj ects). One response on the blink lever resulted in

10 sec of a blinking houselight (additional responses on either lever during this 10 sec period did

not have programmed consequences, but were recorded), whereas one response on the

continuous lever resulted in 10 sec of a continuously illuminated houselight. A response only

illuminated the appropriate stimulus when there was no stimulus being presented at the time of

the response. The lever assignments remained the same for the first two days of Stimulus









Evaluation (e.g., left blink, right continuous), and were switched for the third and final day (e.g.,

left continuous, right blink) to assess whether side biases had developed.

Lever training. The day after the final pre-test session, research assistants trained lever

pressing by giving subj ects 45 mg sucrose pellets when successive approximations of lever

pressing were made. These initial training sessions ended after 30 min or after 20 responses on

each lever. One response resulted in a food pellet, with the exception that after three consecutive

responses on the same lever food could only be earned by pressing the other lever. Hand shaping

continued for up to three additional sessions, as needed. Once lever pressing was acquired, rats

continued to earn food for pressing levers but were required to strictly alternate between the two

levers such that the second consecutive response on one lever did not result in food. These

alternation sessions lasted for a maximum of 30 min or until 30 responses had been made on

each lever, on seven separate days. The houselight was continuously illuminated during all lever

training sessions.

Discrimination training. After rats were trained to press both levers, the Discrimination

Training condition began. During the last minute of the blackout period, all three LEDs above

each lever were illuminated to signal the beginning of the session. The LEDs turned off after 1

min and the houselight was simultaneously illuminated, either blinking or continuous

(component type was randomly determined at the beginning of each session). Components

alternated between a continuously illuminated houselight (S+) which signaled periods when food

was available for pressing the left, food-extinction, lever (i.e., food components) and a blinking

houselight (S-) which signaled periods when food was not available for pressing the food-

extinction lever (i.e., extinction components). Initially, the first response on the food-extinction

lever after an average of 15 sec (i.e., variable-interval 15 sec [VI 15]) resulted in a food delivery.









After seven sessions, this value was increased to a VI 20 sec schedule of food delivery. VI

distributions were composed of 15 values based on the Fleshler-Hoffman distribution (Fleshler &

Hoffman, 1962). Components lasted an average of 60 sec (rectangular distribution ranging from

10 to 1 10 sec); however, if the extinction component was scheduled to change to a food

component, it would not change until 5 sec elapsed without a response on either lever (i.e.,

differential reinforcement of other behavior [DRO] 5 sec). The DRO procedure was

implemented to prevent adventitious pairings between responding during extinction components

and subsequent transitions to food components. Aside from the DRO contingency, responses on

the right, observing, lever did not have any additional programmed consequences during

Discrimination Training.

Discrimination Training lasted a minimum of 65 days and until all but two subj ects

displayed a discrimination index (DI) of 0.75 or higher. Discrimination index was calculated by

taking the rate of responding on the food-extinction lever in the presence of the S+, divided by

the sum of the rate of responding on the food-extinction lever in the presence of the S+ and S-.

Values could range from zero to unity, with higher values indicating greater stimulus control.

Two subj ects (R223 and R224) did not reach the 0.75 DI criterion. The DRO requirement was

then increased from 5 to 10 seconds for these two subj ects. This effectively increased DI (0.53 to

0.73 for R223; 0.59 to 0.66 for R224). Because of this improvement, all subj ects were moved to

the next condition.

Observing response procedure. The DRO contingency was discontinued when the

observing response procedure began. During the last minute of the blackout period, all three

LEDs above each lever were illuminated to signal the beginning of the session. At the end of one

minute, the LEDs turned off making the chamber dark. At the beginning of the session, the










computer randomly determined whether a VI 20 sec food or extinction component would be in

effect; however, the stimulus corresponding to the selected component was only shown

contingent on a response to the right, observing lever. Initially, only one response (i.e., FR 1) on

the observing lever was required to illuminate the schedule correlated stimulus for 10 sec. If a

component was scheduled to end during the 10 sec stimulus presentation, the component

continued until the stimulus turned off. Immediately after the stimulus turned off the schedule

changed. For example, if after 5 sec of S+ stimulus presentation the food component was

scheduled to switch to extinction, the S+ and food schedule would remain in effect for the final 5

sec of the stimulus presentation and the component would immediately change to extinction

when the stimulus turned off. For the first five sessions of the observing response procedure, the

first five observing responses resulted in the S+ stimulus being presented. If the extinction

component was in effect when one of the first five responses occurred, the component switched

to VI 20 sec food (Shahan, 2002). Otherwise, components alternated every 60 sec on average as

described for Discrimination Training.

After 11 sessions under the conditions described above, the VI 20 sec food schedule was

increased to a VI 30 sec food schedule. Ten sessions later the observing response requirement

was increased from FR1 to VI 5 sec. Thus, the terminal parameters of the observing response

procedure consisted of a VI 30 sec food schedule alternating with extinction approximately every

60 sec, and stimuli were presented for 10 sec on a VI 5 sec schedule. Unless otherwise noted, all

sessions from this point forward were arranged according to these terminal parameters and were

30 min in duration.

Subj ects experienced the terminal parameters for 26 sessions, after which they were

stratified into three groups of six based first on observing response rate, second on DI, and third,










when possible, on food-extinction response rates in the presence of the S+ and S-. The three

groups differed with respect to the dose of nicotine administered during all subsequent

conditions: Vehicle (0 mg/kg nicotine), 0.3 mg/kg Nicotine (base), or 0.56 mg/kg Nicotine

(base) .

Drug administration. For 70 sessions, subjects received daily pre-session subcutaneous

inj sections of the dose they were assigned. The 70 session Drug Administration condition was

divided into four sections for the purposes of clarity and data analysis: Acute administration

(sessions 1-5), Chronic administration (sessions 31-35), Resistance to Extinction (sessions 36-

40), and Extended Chronic administration (sessions 66-70). Everything operated as normal

during the Resistance to Extinction sessions, except that food was no longer delivered during

food components. After five sessions food was reintroduced.

Data Analyses. One subj ect in the Vehicle group never acquired the observing response,

defined as an increase in observing responses relative to the Stimulus Evaluation pretest

condition. Thus, this subj ect was eliminated from all analyses, leaving the Vehicle group with n

= 5.

To investigate responding during the pretest conditions, a repeated-measures ANOVA

was conducted on the left and right levers during the Operant and Stimulus Evaluation

conditions. Because of repeated measurement, all results were adjusted for sphericity using

Huynh-Feldt correction (Huynh & Feldt, 1976). An additional ANOVA was conducted on mean

right lever response rates during the Operant Evaluation, Stimulus Evaluation, the last Hyve

sessions of Discrimination training, and the first Hyve sessions of the Observing Response

Procedure. Tukey's HSD post-hoc analyses were performed when significant main effects were

found.










ANOVAs were also performed to determine whether there were significant differences

across the three drug administration groups (Vehicle, 0.3 Nicotine, 0.56 Nicotine) just prior to

the Drug Administration condition in mean DI, observing response rates, and food-extinction

response rates in the presence of the S+ and S-.

To determine whether there were differences across groups during the Acute, Chronic,

Resistance to Extinction, and Extended Chronic sections of the Drug Administration condition,

ANOVAs were conducted, with Huhyn-Feldt corrections and Tukey's HSD post-hoc analyses

were performed when significant main effects were found.

Finally, to evaluate the presence of rate-dependent effects, linear regression analyses

were performed on the log percentage of pre-drug response rates graphed as a function of the log

pre-drug response rates during the Acute, Chronic, and Extended Chronic sections of the Drug

Administration condition. All response types (i.e., observing, responses maintained by food, and

responses during extinction) were included in the same graph to generate a suitable amount of

variability in pre-drug response rates to assess rate dependence.

All results were deemed statistically significant at p < 0.05.

Results

Because subj ects had not yet been divided into groups during the pretest conditions, these

conditions were evaluated with all subj ects considered as one group. Response rates (resp/min)

were low on both the right and left levers during the two days of Operant Evaluation (mean +

SEM right lever = 0.25 & 0.04 resp/min; left lever 0. 15 & 0.03 resp/min). Response rates

increased on both levers during the Stimulus Evaluation pretest (mean + SEM right lever = 0.85

+ 0.12 re p/min; left lever = 0.67 + 0.10 res /min There was a si nificant difference across

conditions (F (1,83) = 28.48), but there was no significant difference in response rates between

the two levers and there was no lever x condition interaction.










Because there was no difference in responding between the right and left levers, Figure 2-

2 shows only responding on the right lever, which later became the observing lever. The first two

panels of Figure 2-2, labeled "Operant Evaluation" and "Stimulus Evaluation," respectively,

show the mean and standard error of the mean (+SEM) for all subj ects during the protests. The

third panel of Figure 2-2 shows responding during the last five days of Discrimination Training.

The only consequence for pressing the lever during this condition was the DRO contingency that

prevented transition from the extinction to the food component. Response rates during the last

five days of the Discrimination Training condition averaged 0.78 resp/min (+SEM = 0.08), and

were not significantly different from response rates during the Stimulus Evaluation pretest.

Finally, the fourth panel of Figure 2-2 shows the rates of responding during the first five days of

the Observing Response condition. Response rates increased during this condition to an average

of about 4.02 resp/min (+SEM = 0.23). There was a significant difference across conditions (F

(3,25 1) = 1 14. 1) and post-hoc analyses revealed that responses during the first five days of the

Observing Response condition were significantly higher than the three previous conditions,

which were not significantly different from each other.

Mean DI, observing response rate, and food-extinction response rates in the presence of

the S+ and S- were computed based on the last five sessions of the Observing Response

condition, just prior to the Drug Administration condition, for each subj ect in a group. These

sessions were used to determine group assignment and the means and SEMs for each group are

shown in Table 2-2. There were no significant differences between groups on any of the

measures.

Figure 2-3 shows mean (+SEM) food-extinction response rates during S+ components

(top graph) and S- components (middle graph), as well as observing response rates (bottom










graph). Table 2-3 displays the means (+SEM) of the response rates displayed in Figure 2-3.

Figures 2-4, 2-5, and 2-6 show response rates for individual subj ects on the Food-Extinction

lever in the presence of the S+, S- and Observing lever, respectively, with a different subj ect in

each individual graph and groups organized in columns (from left to right: Vehicle, 0.3 Nicotine,

0.56 Nicotine). All of the graphs in Figures 2-3 through 2-6 are organized the same, with the first

panel of each graph showing the last Hyve sessions of the pre-drug condition, the second panel

showing the acute sessions, the third panel showing the chronic sessions, and the fourth panel

showing the extended chronic sessions.


The top graph in Figure 2-3 shows that food-extinction response rates in the presence of

the S+ were high for all groups during the pre-drug condition, and there were no significant

differences across groups. Response rates in the presence of the S+ remained high throughout the

three Drug Administration sections shown in Figure 2-3, and there were no significant

differences in response rates across groups during any of the sections.


The middle graph in Figure 2-3 illustrates that food-extinction response rates during S-

presentations were lower during the pre-drug condition than food-extinction response rates

during S+ presentations, but again there were no significant differences across drug

administration groups. During the Acute Drug Administration section there was a significant

difference across groups (F (2,81) = 4.472) and post-hoc analyses revealed that the 0.3 Nicotine

group responded significantly more than the Vehicle and 0.56 Nicotine groups (Table 2-3).

There were also significant differences in response rates across groups during the Chronic Drug

Administration section (F (2,81) = 3.35). However, unlike during the Acute section, during the

Chronic section post-hoc analyses revealed a marginally significant (p=0.05) increase in the 0.56

Nicotine group. Finally, there were significant differences in response rates across groups during









the Extended Chronic Drug Administration section (F (2,81) = 3.69). Post-hoc analyses revealed

that the Vehicle group responded significantly more than the 0.3 Nicotine group, but not more

than the 0.56 Nicotine group. There were no significant differences between the 0.3 and 0.56

Nicotine groups.


The bottom graph in Figure 2-3 shows that observing response rates during the pre-drug

condition were similar across groups (also see Table 2-3). Acute nicotine administration resulted

in a significant difference across groups (F (2,81) = 7.25), and post-hoc analyses revealed that

response rates for the 0.3 Nicotine group were significantly higher than response rates for both

the Vehicle and 0.56 Nicotine groups. Similarly, there were significant differences across group

during the Chronic Drug Administration section (F (2,81) = 6.58). During Chronic, however,

post-hoc analyses revealed a significant increase in response rates for both the 0.3 and the 0.56

Nicotine groups, relative to the Vehicle group. This significant increase in response rates

continued (F (2,81) = 13.62) for both groups after extended exposure to nicotine. It is worth

noting that there was a decreasing trend in observing responses across the last five sessions of the

Chronic section for the 0.3 Nicotine group; however, after Resistance to Extinction observing

responses increased and remained stable at this higher rate. The mean effects shown in Figure 2-

3 are consistent with the majority of the individual subj ect effects shown in Figures 2-4 through

2-6 for each response type.


The Chronic Drug Administration section immediately preceded the five days of

Resistance to Extinction. Because response rates were different across groups for each of the

three responses during the Chronic section, it was necessary to control for these differences to

evaluate resistance to extinction (Nevin, 1974). Figure 2-7 shows that, as expected, all three

response types decreased across the five days of Resistance to Extinction. There were no










significant differences in the proportions of food-extinction responding in the presence of the S+

(top graph) or in the proportions of observing responses (bottom graph) across the five extinction

sessions. There were also no significant differences in the food-extinction proportions of

responding in the presence of the S- (middle graph) during the first four days of extinction. On

day five, there was a significant difference across groups (F (2, 14) = 9.982) and post-hoc

analyses revealed that subj ects in the Vehicle group had significantly higher proportions of

res onding than subj ects in the 0.3 and 0.56 Nicotine tro s (mean + SEM Vehicle = 0.3 8 +

0.04; 0.3 Nicotine = 0.18 + 0.05; 0.56 Nicotine = 0.13 + 0.03).

To examine rate-dependent effects, scatter plots were created for each group of subj ects.

Pre-drug response rates were calculated by averaging response rates during the last five sessions

of the Observing Response procedure that immediately preceded the Drug Administration

condition. Log percentage of pre-drug rates were calculated and graphed as a function of log pre-

drug rates. Three separate plots were created for each condition across the three groups, with all

of the response types (i.e., observing, food-extinction S+ and S-) included in each plot, as shown

in Figure 2-8. Lines were fitted to the data by least-squares regression and the fitted parameter

values for the slope and y-intercept, as well as the r2 ValUe, for each line is shown in Table 2-4.

There were seven instances, out of nine, in which the fitted slopes were significantly different

from zero: a positive slope for the Vehicle group during the Chronic section, and negative slopes

for the 0.3 and 0.56 Nicotine groups during all three sections.

Discussion

Experiment 1 supports the MEO account by showing that nicotine increased responding

maintained by conditioned reinforcers (i.e., visual stimuli that had been associated with food

availability). Extended, repeated exposure to nicotine more than doubled the number of










responses per 30 min session from approximately 125 responses, seen with the Vehicle group, to

over 250 responses, seen with the two nicotine groups (see Table 2-3). The increases in the

present study were reliable and robust, and sustained changes in responding over the course of

the experiment were specific to responses maintained by conditioned reinforcers. That is,

nicotine did not reliably increase responding maintained by food reinforcers at any point, and

any increases in responding during extinction (e.g., 0.3 Nicotine during Acute and 0.56 Nicotine

during Chronic) were not sustained.


To investigate further the MEO account of nicotine, resistance to extinction was

compared across groups of rats given nicotine or vehicle. If nicotine increased the reinforcing

value of the conditioned reinforcers, then this should have resulted in a context with a richer

amount of reinforcement relative to the vehicle control group. According to behavioral

momentum, responses occurring in the context of a richer amount of reinforcement should be

more resistant to extinction (Nevin, 1974; Nevin & Grace, 2000). Instead, nicotine did not affect

resistance to extinction on any of the response types studied. Several possibilities might account

for this lack of effect. One possibility is that nicotine did not serve as a 1VEO in the present

study, and that the increases in observing responses were due to a different mechanism. One

alternative mechanism that has been discussed is that nicotine generally increases lever pressing

because of its effects on activity (Frenk & Dar, 2004). However, responding during extinction

served as a control for detecting general increases in motor capacity, and nicotine did not

increase responding during extinction.


On the other hand, a lack of effect of nicotine on resistance to extinction may have been

due to limitations in the behavioral momentum account of resistance to extinction. The current

study was designed to compare resistance to extinction across subj ects, whereas behavioral









momentum theory has been almost entirely developed by comparing resistance to extinction

within subj ects and within sessions. The typical paradigm for studying behavioral momentum is

to use a multiple schedule comprised of a rich and lean schedule, with greater resistance to

extinction in the rich relative to the lean schedule (for a review see Nevin & Grace, 2000). In

fact, one study was unable to demonstrate greater resistance to extinction in a rich relative to a

lean schedule when resistance was compared across conditions or sessions with simple schedules

of reinforcement, rather than within the same session (Cohen, Riley, Weigle, 1993).


Furthermore, it has not yet been demonstrated that higher rates of conditioned

reinforcement will necessarily result in greater resistance to extinction, as it occurs with higher

rates of primary reinforcement. Shahan and Podelsnik (2005) used a complex multiple observing

response procedure, whereby a rich component resulted in a higher rate of conditioned

reinforcement, contingent on observing responses, relative to a lean component. Observing

response rates were higher in the rich component, but subj ects did not demonstrate greater

resistance to extinction in the rich component relative to the lean component. The authors

explained that two levels of conditioning would need to take place for resistance to occur with

conditioned reinforcers: (1) pairings between the primary reinforcers and the stimuli that are

being established as conditioned reinforcers and (2) pairings between the higher rate or amount

of conditioned reinforcers and the context in which they occur. The same can be said of the

current study in that the visual stimuli were being paired with food during S+ presentations, and

subj ects in the two nicotine groups presumably experienced an experimental context with a

larger amount of reinforcement than subj ects in the Vehicle group. At this time it is not clear

whether the behavioral momentum theory of resistance to extinction applies to such second-order

levels of conditioning because of a general lack of research designed to study such phenomena.










The present study also had the advantage of generating a range of response rates, making

it possible to evaluate whether nicotine produced rate-dependent effects (Table 2-4 and Figure 2-

8). Of the nine regression analyses, six resulted in negative slopes that were significantly

different from zero (increases in low pre-drug rates and decreases in high pre-drug rates). It is

important to note that there was never more than 21% of the variance accounted for by the linear

equations, as indicated by the r2 ValUeS shown in Table 2-4. Nevertheless, the data do suggest a

tendency for rate-dependent effects of nicotine.


Finally, protests were conducted to determine whether the illumination of a continuous

and blinking houselight would function as a primary reinforcer, similar to what other researchers

have demonstrated (Barry & Symmes, 1963; Goodrick, 1970; Kiernan, 1965; Marx, Henderson,

Roberts, 1955; Roberts, Marx, Collier, 1958; Robinson, 1959; Segal, 1959; Tapp, Mathewson,

Simpson, 1968; Stewart, 1960), and whether the stimuli would later come to function as

conditioned reinforcers. There was, indeed, an increase in lever pressing during the Stimulus

Evaluation condition, relative to the Operant Evaluation condition, suggesting a weak primary

reinforcing function of the stimuli. During Discrimination Training the stimuli were associated

with a multiple schedule of food and extinction conditions which have been shown to establish

stimuli as conditioned reinforcers (Dinsmoor, 1983). During the first five days of the Observing

Response condition, responses that turned on a houselight increased to more than four times the

response rates seen during the Stimulus Evaluation condition. In fact, observing response rates

continued to increase with extended exposure to the procedure (compare Figures 2-2 and 2-3).

The increases were not simply due to the presence of food during the sessions, which may have

caused some arousal (Killeen, Hanson, Osborne 1978), because there were no significant










increases during Discrimination Training. This finding suggests that the stimuli were established

as conditioned reinforcers.











Table 2-1. Hypothetical effects of nicotine on responding maintained by each of the response
types investigated with the observing response procedure

Outcome
Response #1 #2 #3 #4
Food-extinction (S+) --
Food-extinction (S-) -- -- --
Observing --










Table 2-2. Mean + SEM DI, Observing response rate, food-extinction response rates in the
presence of the S+ and S- from the five sessions prior to the Drug Administration
condition


Group D.I. Observing Food-extinction Food-extinction
(S+) (S-)
Vehicle 0.73 + 0.02 5.63 + 0.53 37.62 + 1.01 14.68 + 1.65
0.3 Nicotine 0.73 + 0.02 6.21 + 0.97 37.34 + 3.34 15.97 + 2.34
0.56 Nicotine 0.74 + 0.02 5.62 + 0.76 47.31 + 5.54 16.09 + 1.47










Table 2-3. Mean + SEM response rates just prior to and during the Drug Administration
condition for food-extinction response rates in the presence of the S+ and S-, and for
observing responses
Pre-Drug Acute Chronic Extended Chronic


Food-Extinction (S+)
41.27 + 1.32 46.59 + 2.92
45.24 + 3.54 38.88 + 2.56
34.45 + 4. 14 38.83 + 2.27
Food-Extinction (S-)
15.20 + 1.82 a 12.07 + 1.90 c

22.78 + 2.48 ab 11.74 + 0.99 d

15.87 + 1.45 b 15.97 + 1.05 c d

Observing Responses
5.52 + 0.48 a 4.65 + 0.52 c d

9.69 + 1.05 ab 7.32 + 0.89 c

5.84 + 0.86 b 8.19 + 0.56 d


Vehicle
0.3 Nicotine
0.56 Nicotine


Vehicle

0.3 Nicotine

0.56 Nicotine



Vehicle

0.3 Nicotine

0.56 Nicotine


37.62 + 1.01
37.34 + 3.34
47.31 + 5.54


14.68 + 1.65

15.97 + 2.34

16.09 + 1.47



5.63 + 0.53

6.21 + 0.97

5.62 + 0.76


46.54 + 2.31
42.84 + 2. 11
42.13 + 2.50


15.53 + 1.55 e

11.33 + 0.94 e
14.54 + 0.98



4.25 + 0.38e f

7.99 + 0.69 e

9.02 + 0.77'


Note: Within each response type, values in each column indicated by the same superscripted
letter (e.g., a) were significantly different from each other with p < 0.05.










Table 2-4. Fitted parameter values and corresponding r2 for each linear regression applied to the
rate-dependent graphs shown in Figure 2-8.
Phase Group Slope y/-intercept r2
Vehicle 0.16 102 0.01

Acte 0.3 Nicotine* -2.30 211 0.15
0.56 Nicotine* -2.00 176 0.06


Vehicle* 1.27 71 0.12
Chronic 0.3 Nicotine* -0.8 125 0.08
0.56 Nicotine* -3.2 252 0.16


Vehicle 0.53 99 0.01
Extended 0.3 Nicotine* -1.8 169 0.21
Chronic 0.56 Nicotine* -3.7 282 0.13

Note: Asterisks denote slopes that were significantly different from zero.
Vehicle: Chronic F (1,73) = 9.9;
0. 3 Nicotine: Acute F (1,88) = 16.67; Extended Chronic F (1,88) = 24.02
0.56 Nicotine: Acute F (1,84) = 1 1.74; Chronic F (1,88) = 164.53; Extended Chronic F
(1,88)= 82.4














Operant Evaluation: Operant lei el, Visual stimulii presented n on-contingently

Stimulus Evalu ation: Visual stimuli :ontingent on lever press
Han dsh apin gto press levers usin food rei enforcers
Diciin ation Trai ni ng: MulIti ple sch edu le, S+ an d S- correlated with food or exti ncti on
Obserlnrg Resper ce Procedure
Pre-dru g

Icute Chronic Resistance Exten ded Ch ronic
Session 0 3 6 ~17 ~97 ~145 ~215


Dru g admin istration: Su bcutaneous 0.3,
0.56 m g/k n icotin e, or veh i le



Figure 2-1. Experiment 1 schematic. Shows the progression of conditions throughout the
experiment. Vertical lines indicate the beginning of a condition and the number below
the line is the approximate session number. Bracketed areas indicate different sections
within the observing response procedure that were subj ected to statistical analyses.














Operant Stimulus
evaluation evaluation


Last five days
of discrimination
training


First five days
of observing


5-

-



Oj


1,
-n

0



0-


~vT~,


Session


Fi ure 2-2. Pretests. Mean + SEM res /min for all subj ects are shown. The first two panels show
resp/min on the right (future observing) lever during the Operant and Stimulus
Evaluation protests. The third and fourth panels show resp/min on the right lever
during the last Hyve sessions of Discrimination Training and the first 5 days of the
Observing Response procedure, respectively. The third and fourth panels represent 10
consecutive sessions.


Il~'r~
























Food-Extinction Responses (S-)

rI


Session


-*- Vehicle
-o- 0 3 Nicotine
-E- 0 56Nicotine


Figure 2-3. Mean (+SEM) Food-Extinction S+, S- and Observing Responses for the Vehicle
group (filled circles), the 0.3 Nicotine group (open circles), and the 0.56 Nicotine
group (open squares). The first panel of each graph shows the last five sessions of the
Observing Response condition, immediately preceding the Drug Administration
condition. The next three panels represent five sessions from three of the sections of
the Drug Administration condition: Acute, Chronic, Extended Chronic. The top graph
(a) shows resp/min on the food-extinction lever in the presence of the S+ (i.e., food-
maintained responses). The middle graph (b) shows resp/min on the food-extinction
lever in the presence of the S- (i.e., responses during extinction) and the bottom graph
(c) shows resp/min on the observing response lever. Note different y-axes for each of
the three response types.


Food-Extinction Responses (S+)
Observing Acute Chronic Extended
(PeDu) (Days 1-5) (Days 31-35) Chronic








































































































Figure 2-4. Individual subj ect data showing Food-Extinction responses on the S+ for the last five

sessions of the Pre-Drug, Acute, Chronic, and Extended Chronic sections. Each graph

is a different subj ect, with drug administration group organized in columns, from left

to right, showing the Vehicle (filled circles), 0.3 Nicotine (open circles), and 0.56

Nicotine groups (filled triangles), respectively.


Food-Extinction (S+)

0 3 Nicotine

Pre-Drug Acute Chronic Extended

R215


Vehicle
Pre-Drug Acute Chronic Extended

R214


0 56 Nicotine
Pre-Drug Acute Chronic Extended
R217


80


*4~f~


120 R220
100


R218


4~L
C-~
Y
Y-r-


140

120 R224 1 R226


R221


i~40



S140


Y
B
o


Ul, 4
c


R222













R223


120
R225
100

80




20


140

120 R230

100


|R228


R229-4


Session















Food-Extinction (S-)
0 3 Nicotine
Pre-Dmg Acute Chromec Extended
R215


Velucle
Pre-Dmg Acute Chromec Extended
R214


0 56 Nicoline
Pre-Dmg Acute Chromec Extended
R217


10

0
60

50 R220

40


R218


4
4 t
L


0
60

50 R24

40

30

20

10

60

50R225
40


R221


R226


rt
4 4
i, r-


J
v


50 R230


R229


\J`


|R231


f\ I fr,
4
~
i


Session


Figure 2-5. Individual subj ect data showing Food-Extinction responses on the S- for the last five

sessions of the Pre-Drug, Acute, Chronic, and Extended Chronic sections. Each graph

is a different subj ect, with drug administration group organized in columns, from left

to right, showing the Vehicle (filled circles), 0.3 Nicotine (open circles), and 0.56

Nicotine groups (filled triangles), respectively.













Observing
0 3 Nicoline
Pre-Drug Acute Chromec Extended
R215


Velucle
25Pre-Drug Acute Chromec Extended
20R214




10i


0 56 Nicotine
Pre-Drug Acute Chromec Extended
R217


4
* 11
ri
~-4 u


II


R220


R219


R221














R222I t


R224


0


220 R225


R230 R2


\ I .I', :


R231


R229


0P

Session

Figure 2-6. Individual subj ect data showing Observing responses for the last five sessions of the
Pre-Drug, Acute, Chronic, and Extended Chronic sections. Each graph is a different

subj ect, with drug administration group organized in columns, from left to right,
showing the Vehicle (filled circles), 0.3 Nicotine (open circles), and 0.56 Nicotine

groups (filled triangles), respectively.













Food-Extinction Responses (S+)


12-

1 0 ----

08-

06-

04-

02-



Food-Extinction Responses (S-)
14-

12-















S08-


906-

04-



234

ObExtinctieon Sesso



Fiue2-.RsitnetoEtncin Ma EMpoorinofCrnc epmi o sbet

inteVhcl ru flldcrls) h ictn rup(pncrle) n h

0.6Nctnegop(pe qae).Tetpgap a hwspootono hoi

repmnontefo-etnto lvri hepeec o h +(iefo-mitie

repne).Temdlegah(b hw rooto f hoi rs/i n h od





extinction leve in the presene oftheio S- (ioersoss uigetncin n h





bottomie rup(pn qars.Th o graph (c) shows proportion of Chronic rs/i nteosrigrsos




lever. The dotted line at 1.0 indicates no change from Chronic, with values above and

below the line indicating increases and decreases, respectively.












Vehicle


0.3 Nicotine


0.56 Nicotine


1000


o
0
0


Acute


100 8~


10















a,10


Chronic


Extended
Chronic 0


1001


100


A Obsenring
*Food-Extinction Responses (S+)
o Food-Extinction Responses (S-)


Pre-Drug (log scale)


Figure 2-8. Rate-dependent scatterplots. Rate-dependent scatter plots for the Vehicle (left
column), 0.3 Nicotine (middle column), and 0.56 Nicotine (right column) Groups.
Shown are the log percentage of pre-drug response rates plotted as a function of log
pre-drug response rates for the Acute (top row), Chronic (middle row), and Extended
Chronic (bottom row) sections. All three response types are shown together on each
plot observing (filled triangles), food-extinction S+ (filled circles), and food-
extinction S- (open circles). Equations, with the fitted parameter values and r2 can be
found in Table 2-4


8
I~t
r r
1 Ci
o


- -r


AA' O
to


dr
r Z


6
o


fr t o d

0 8


t









CHAPTER 3
Experiment 2
Introduction

The results of the Stimulus Evaluation condition of Experiment1 showed that rates of

responding increased slightly, relative to the operant level, when the visual stimuli were made

contingent on a response. This finding suggested that the stimuli may have initially functioned as

weak or moderate primary reinforcers. It is important to note, however, that the Operant and

Stimulus Evaluation sessions were brief (10 min) and were only conducted over a five day

period to avoid over-exposure and perhaps conditioned inhibition to the stimuli that would

later be used as conditioned reinforcers (Lubow & Moore, 1959). It is possible that the increases

seen during the Stimulus Evaluation condition were due to general increases in lever pressing

that would have occurred over time, regardless of the consequences arranged. Thus, although the

data suggested that the stimuli did serve a primary reinforcing function, this conclusion was only

tentative.


Other researchers have suggested that under some conditions visual stimuli can function

as weak or moderate primary reinforcers (Barry & Symmes, 1963; Goodrick, 1970; Kiernan,

1965; Kish, 1966; Marx, Henderson, Roberts, 1955; Roberts, Marx, Collier, 1958; Robinson,

1959; Segal, 1959; Tapp, Mathewson, Simpson, 1968; Stewart, 1960). A recent study compared

groups of rats to determine the effects of pre-session inj sections of nicotine on responding

maintained by two visual stimuli that generated different levels of responding: (a) turning off the

houselight in an operant chamber for 5 sec, which resulted in approximately 35 responses during

a 60 min session, and (b) turning on a stimulus light in an operant chamber for 5 sec, which

resulted in approximately 10 responses during a 60 min session (Palmatier et al., 2007). Nicotine

administration increased responding in the group of rats whose behavior was maintained by









turning off the houselight, to about 100 responses per session, but there were no significant

increases in responding in the other group of rats whose behavior was maintained by turning on

the stimulus light. All rats in the study were initially trained to press the active lever using food

as a consequence for pressing, in the same way that active lever responses are typically trained in

nicotine self-administration studies (Caggiula et al., 2001; Chaudri et al., 2006; Donny et al.,

2003). As discussed earlier, Frenk and Dar (2004) posited that lever training history may

contribute to the nicotine-induced increases seen only on the active lever. Thus, a more

systematic investigation of lever training history is warranted.


Purpose of Experiment 2

Experiment 2 sought to: (1) explore the putative primary reinforcing function of the

visual stimuli used in Experiment 1 (i.e., turning on a houselight), as well as the visual stimuli

used in a number of nicotine self-administration studies (i.e., turning off a houselight; Caggiula

et al., 2002; Palmatier et al, 2007), (2) determine whether different histories of lever training

would influence the apparent primary reinforcing effects of the visual stimuli, (3) assess whether

nicotine would have different effects on responding, as a function of lever training history and

the type of visual stimulus (turning on versus turning off the houselight), and (4) further

investigate the rate-dependent effects of nicotine. The lever training protocol and general

procedural design were based on the procedures used by Caggiula and colleagues (e.g., Caggiula

et al., 2002b) to investigate nicotine self-administration. Such procedures consisted of food-

depriving subj ects and then exposing them to two sessions of lever training with food

reinforcers, then gradually increasing the FR schedule of contingent stimulus presentations (five

sessions of FR1, five sessions of FR2, ending with a terminal FR5 schedule).









Methods


Subj ects

Eight experimentally naive male Long-Evans rats (Harlan; Indianapolis, IN), maintained

at 85% (326-408 g) of their 150 day old ad libitum weights, served as subjects. Subjects were

housed in individual home cages with bedding, and received free access to water and post-

session supplemental rodent chow (Lab Diet Rodent Diet; Formula 5001). The colony room was

on a 12:12 hour light dark cycle (light from 8am-8pm).


Apparatus and Materials

Sessions were conducted in 8 Med Associates@ extra tall operant chambers. The operant

chambers were identical to those used during Experiment 1 described earlier. Med-PC software

and hardware were used to program experimental events on a computer located in the

experimental room. The computer also collected and stored data after each session. On drug

delivery days, nicotine ([-]-Nicotine Hydrogen Tartrate Salt; Sigma, St. Louis, MO), dissolved in

potassium phosphate buffered saline, was used.

Procedure

Subj ects were randomly assigned to one of two groups, differing only with respect to

their lever training history. One group of subj ects (n = 4) was trained to press both the right and

left lever, hereafter the "Two-Lever" group. The second group of subj ects (n = 4) was trained to

press the right lever only, hereafter the "One-Lever" group. During lever training the only lights

that were illuminated in the chamber were the red LEDs located above each lever. Lever training

took place on two separate days.


Two-Lever Training. Day one of training consisted of research assistants delivering

food for approximations of pressing either the right or left lever, until one response was made on









each lever. From that point forward, one food pellet was delivered for each lever press, with the

restriction that the same lever could not be pressed more than three consecutive times. The

fourth, and all subsequent, responses on the same lever did not have any programmed

consequences, until at least one response on the alternate lever was made. The first day of

training lasted 30 min or until subj ects earned 20 pellets for pressing each lever (i.e., 40 total

pellets). The second day of training was identical to the first, except that there were no time

limits and sessions ended after 37 pellets had been earned for pressing each lever (74 total).


One-Lever Training. As with the Two-Lever group, the first day of training began with

research assistants delivering food for approximations of lever pressing, but for pressing the right

lever only. This continued until one response was made on the right lever, after which only

responses to the right lever were followed by food pellet delivery. Responses on the left lever

never had programmed consequences. The first training day ended after 30 min or after 40

pellets had been earned for pressing the right lever. The second training day was identical to the

first, except that there was no time limit and sessions ended after 74 pellets had been earned for

pressing the right lever.


Lights On and Lights Off. After lever training, subj ects in both the One-Lever and the

Two-Lever groups experienced all of the same procedures. Sessions were conducted at

approximately the same time during the light cycle, seven days per week. To begin, all 6 LEDs

were illuminated five seconds after the subj ect was placed into the operant chamber. A single

response on either lever, or 60 sec without any response, turned off the LEDs and began the 60

min session. The active lever was designated as the right lever. At the beginning of the session

the operant chamber was dark during the Lights On phase, whereas the operant chamber was lit

by the houselight during the Lights Off phase. If no response was made on the active lever,










subj ects remained in a dark or lit operant chamber, depending on the phase. Initially only one

response on the active lever (i.e., fixed ratio [FR] 1) produced 10 sec of the houselight turned on

(Lights On) or off (Lights Off). Additional active lever responses during the stimulus

presentation did not have any programmed consequences, nor did responses on the inactive

lever, but all responses were recorded. After five sessions of FR1 stimulus presentation, the

response requirement was increased to FR2 for an additional five sessions, after which the

response requirement was increased to a final value of FR5. A minimum of 10 sessions at FR5

were required before stability was evaluated. The total number of responses per 60 min session

were deemed stable by visual inspection if there were no increasing or decreasing trends (i.e.,

five consecutive sessions with all responses moving in the same direction) and as long as the

highest or lowest number of responses did not occur during one of the last three sessions.

Conditions changed upon meeting the stability criteria or after a maximum of 30 sessions,

whichever occurred first.


Exposure to the Lights On and Lights Off phases was counterbalanced across subj ects

within a group, such that two subj ects in each group were exposed to the Lights On phase first.

The first phase for all subjects, regardless of whether it was Lights On or Lights Off, was an

ABAB design (with the exception of two subj ects, R25 1 from the Two-Lever group and R257

from the One-Lever group, for whom it was an ABABA and ABAC design, respectively). The A

conditions were baseline with a FR5 schedule of stimulus presentation and without drug

administration. The B conditions consisted of daily subcutaneous (s.c.) administration of 0.3

mg/kg nicotine (base). For subj ect R257 the C condition consisted of daily s.c. administration of

0.56 mg/kg nicotine (base).









Between phases subj ects remained in their home cages for 7 days, but continued to be

weighed daily and maintained at 85% of their ad libitum weights. At the beginning of phase 2,

stimuli were again initially available on a FR1 schedule and the FR requirement increased to 5,

as described earlier. Because subj ect R257 was not responding, lever training was repeated for

this subj ect over a two day period in the same way that it was described earlier. All of the other

subj ects pressed the levers reliably and thus did not need additional lever training. The second

phase for all subj ects consisted of an ABABAC design. For all but subj ect R257, the A and B

conditions were the same as those just described for phase 1 and the C conditions consisted of

daily s.c. administration of potassium phosphate vehicle. The only difference for subj ect R257

was that the B conditions consisted of daily s.c. administrations of 0. 1 mg/kg nicotine instead of

0.3 mg/kg.

Data Analysis. Two, 2 x 2 x 6 repeated-measure ANOVAs were conducted with lever

training group (One-Lever versus Two-Lever), lever (active versus inactive) and condition (three

baseline, two nicotine, one vehicle) compared for each phase (Lights On and Lights Off). An

additional ANOVA was conducted to compare phase (Lights On versus Lights Off), lever, and

condition, regardless of group assignment. All results were adjusted for sphericity using Huynh-

Feldt corrections (Huynh & Feldt, 1976). To evaluate the presence of rate-dependent effects,

linear regression analyses were performed on the log percentage of pre-drug responses graphed

as a function of the log pre-drug responses during the Lights On and Lights Off phases. Active

and inactive responses were included on the same graph and three linear regression analyses

were performed for each phase: (1) both active and inactive responses grouped together, (2)

active responses only, and (3) inactive responses only. All analyses were deemed statistically

significant at p < 0.05.









Results

At the completion of the experiment a computer malfunction was discovered for subj ect

R251 during all but the first two conditions of phase 1 (Lights Off), making the data

uninterpretable. Thus, only the first two conditions are shown and applied to the data analyses

for this subj ect during Lights Off.

Table 3-1 displays the mean (+SEM) proportion of responses allocated to the active lever

during the two days of shaping and during each subsequent experimental condition. During

shaping for the Two-Lever group, both levers were technically active; however, the data are

expressed as a proportion of the lever that became active in subsequent conditions. Two subj ects

in the Two-Lever group (R252 & R253) responded about equally on both levers during shaping,

while the other two subj ects showed a slight preference for the lever that became inactive during

subsequent conditions (R25 1 & R255). All of the subj ects in the One-Lever (R254, R256, R257,

R258) group allocated more responses to the active lever than on the inactive lever during

shaping. During all of the remaining conditions, every subject, regardless of group assignment,

allocated most of their responses to the active lever (almost always 90% or more).


Figure 3-1 shows the last five sessions per condition for each subj ect during the Lights

On phase. As indicated in Table 3-1, a greater number of responses were allocated to the active

lever than to the inactive lever for every subj ect and every condition (mean + SEM: Active lever

= 81.3 + 4.5, Inactive lever: 4.4 + 0.3) with the exception of subj ect R257 during the second

nicotine condition (recall that this subj ect received a 0.56 mg/kg dose of nicotine during this

condition) this difference was statistically significant (F (1,188) = 425.6). There was a

significant effect of condition (F (5, 188) = 23.8), as well as a significant lever x condition

interaction (F (5,188) = 23.6), with nicotine reliably increasing responses on the active lever










(mean + SEM = 126.7 + 14.0), relative to baseline (mean + SEM = 51. 7 + 6.9) and vehicle

conditions (mean + SEM = 65.2 + 11.0), but not reliably increasing responses on the inactive

lever. There were no significant lever x group or lever x group x condition interactions.


Likewise, Figure 3-2 shows the last five sessions per condition during the Lights Off

phase. As during the Lights On phase, a greater number of responses were allocated to the active

lever than to the inactive lever for every subj ect and every condition (mean + SEM: Active lever

= 13 5.1 + 8.6, Inactive lever: 4.8 + 0.4) with the exce tion of the first baseline condition for

subj ect R255 (F (1,188) = 375.0). Again, there was a significant effect of condition (F (5, 188) =

33.2) and a significant lever x condition interaction (F (5, 188) = 34.2), with nicotine reliably

increasing active (mean + SEM = 228.3 + 26.6) but not inactive, res onses relative to baseline

(mean + SEM = 74.5 + 11.6) and vehicle (mean + SEM = 117.7 + 18.7) conditions. As before,

there were no lever x group or lever x group x condition interactions. Furthermore, there was a

significant lever x phase interaction (F (1, 378) = 52.9), whereby a greater number of responses

occurred on the active lever during the Lights Off phase (mean + SEM = 135.1 + 8.7) than

during the Lights On phase (mean + SEM = 81.3 + 4.5).


Figures 3-3 and 3-4 are cumulative response records for one representative rat from each

group (R252 and R258) during the Lights On and Lights Off phases, respectively. Each row for a

subj ect shows the final session from a condition. Deflections in the record represent the

beginning of the 10 sec stimulus presentation, and the pen resets at the end of the 10 sec.

Responses that occurred after the deflection took place during the stimulus presentation. In both

phases, the slopes became steeper during nicotine conditions, relative to baseline and vehicle

conditions. Additionally, pauses between responses appeared to be less frequent and shorter in

duration during nicotine conditions. It is also important to note that during all conditions, it was









rare for a response to occur during the stimulus presentation. Table 3-2 shows the proportion of

stimulus presentations during which at least one response occurred (active or inactive). For most

subj ects under most conditions, less than 40% of the stimulus presentations contained a response.

One subj ect, R251i, was more likely than all the other subj ects to respond during a stimulus

presentation.

The cumulative response records also revealed two distinct patterns of responding during

nicotine administration conditions, which warranted further investigation. One pattern was an

increase in response rates during the first 5-10 min of the session that diminished during the

remainder of the session, as seen for both subj ects during the Lights On phase (Figure 3-3). The

other pattern was a constant high rate of responding throughout the entire session, as seen during

both nicotine conditions for R258 and the second nicotine condition for R252 during Lights Off

(Figure 3-4). All other subjects, except R257, showed one or both of these patterns during

nicotine administration conditions. Time course analyses were conducted on all of the last Hyve

sessions of each condition for both the Lights On and the Lights Off phases to further investigate

these patterns. Because there were no differences between lever training groups, all subj ects

were evaluated as one group. Furthermore, because post-hoc analyses and visual inspection of

the data did not reveal a significant difference across subsequent exposures to a particular

condition (e.g., the first versus the second exposure to baseline), such conditions were collapsed

into one. Shown in Figure 3-5 are the mean (+ SEM) number of responses during each 2 min bin

of the 60 min session. Figure 3-5 shows that there is a peak in responding on both the active and

inactive lever during the first 10 min of the session, regardless of phase. The peak in responding

during this early portion of the session increased substantially during the nicotine conditions, but

only on the active lever.









During the Lights On phase, nicotine-induced increases in responding occurred

throughout the entire session. Although responding remained elevated, relative to baseline levels,

there were no differences in responding between nicotine and vehicle during the last 10 min of

the session because of increases in responding during the vehicle condition. During the Lights

Off phase, the nicotine-induced increases became stable after approximately 10 min and

remained well above baseline levels for the remainder of the session. Again, responding

increased during the vehicle condition during the last 20 min of the session, such that by the end

of the session levels were just slightly less than those seen during the last 20 min of the nicotine

conditions. Although there was a similar peak in responding occurred during the first 5-10 min of

the session on the inactive lever, the total number of responses was very low (note the difference

in scales). There was a general tendency for responding to be higher during the nicotine

conditions; however, these increases were not reliably present during the session and were small

in magnitude.


Finally, to examine rate-dependent effects scatter plots were created for each phase. Pre-

drug responses were calculated by averaging responses during the last five sessions of the

baseline conditions that immediately preceded the nicotine conditions. Log percentage of pre-

drug response rates were calculated and graphed as a function of log pre-drug response rates for

both the active and inactive lever, with both responses shown on the same graph. Lines were

fitted to the data three separate times for each phase, using least-squares regression, and the fitted

parameter values (slope and y-intercept) for each line are shown in Table 3-3, as well as the

percentage of variance accounted for by the line (r2). The first line for each phase was fitted to

both active and inactive responses together, which did not result in slopes that were significantly

different from zero for either phase. The second line was fitted to the active lever only, and for









both phases the slope was negative and significantly different from zero. Finally, the third line

was fitted to the inactive lever only, and again the negative slopes were significantly different

from zero during both phases.

Discussion

Experiment 2 showed that visual stimuli, turning on and turning off a houselight,

functioned as primary reinforcers for rats. Regardless of whether subj ects were initially trained to

press one or both levers, all subj ects eventually showed a strong preference for the active lever.

It is important to note that during lever training, subj ects who were trained to press both levers

allocated their responses equally across the two levers, until food was removed and stimulus

changes were presented contingent on active lever responses only (Table 3 -1, subj ects R251i,

R252, R253, and R255). Thus, visual stimulus change as a consequence in its own right

engendered preference for the active lever for a group of rats who were trained to press both

levers equally often. This finding suggests that the visual stimuli used in the present study

functioned as primary reinforcers.


An alternative account regarding the responses occurring in Experiment 2 is that visual

stimulus change elicited responses, rather than reinforced responses. There are at least two lines

of evidence that make the elicitation account implausible. First, if the stimuli elicited lever

pressing then they should have been just as likely to elicit inactive responses as they were to

elicit active responses, especially for the Two-Lever training group. Second, this account

becomes even less likely when examining Table 3 -2 and the cumulative records of Figures 3 -3

and 3-4, which all show that when the stimuli were present, responding was not likely to occur.

The mean proportion of stimuli that contained a response averaged around 0.32 in other words,

during almost 70% of stimulus presentations no response was made. Furthermore, even with the










reliable, pronounced increases in responding during nicotine conditions, there were no consistent

changes (increases or decreases) in the proportion of stimuli that contained a response.


The present study also had the advantage of generating a range of response rates across

the active and inactive levers, making it possible to evaluate whether nicotine produced rate-

dependent effects (Table 3-3 and Figure 3-6). When active and inactive responses were evaluated

with a single regression analysis, the slopes were not statistically significant during either phase.

However, when active and inactive response rates were analyzed separately, the negative slopes

(increases in low pre-drug rates and decreases in high pre-drug rates) were significantly different

in all four cases. It is important to point out that on the inactive lever, regardless of the phase,

there were increases at the low pre-drug rates and decreases at the high pre-drug rates.

Alternatively, on the active lever there were only a few instances of responses decreasing, all of

which were during the Lights Off phase with subj ect R257 (recall that this subj ect did not show

nicotine-induced increases in responding at any time during this phase). Otherwise, active lever

response rates only increased but to a greater extent, proportionally, with lower pre-drug rates

than with higher pre-drug rates. Similar to Experiment 1, Table 3-3 shows that the percentage of

variance accounted for by the linear regressions were small, in this case never exceeding 12%.

Nevertheless, as with Experiment 1, the data do suggest a tendency for rate-dependent effects of

micotmne.


The results from Experiment 2 provide additional support for the MEO account of

nicotine by showing that responding maintained by primary reinforcing visual stimulus changes

increased when nicotine was delivered. Similar increases were not noted on the inactive lever,

even for subj ects who were initially trained to press the inactive lever with food as a

consequence (Two-Lever group). Nicotine increased responding maintained by both types of









stimulus change (Lights On and Lights Off). The absolute increases in responding in the Lights

Off phase of the current study were comparable with the increases noted by other researchers

(Donny et al., 2003; Palmatier et al., 2007). However, the increases seen in the current study

during the Lights On phase are contrary to the findings by Palmatier et al (2007), who only saw

increases in responding maintained by turning off the houselights. The current study involved

turning on the houselight, from a dark chamber, whereas Palmatier et al. had subj ects turning on

a stimulus light located above the lever. Furthermore, the current study maintained a greater

number of responses per session during the Lights On phase than were seen in the lights on

group in the Palmatier et al study. Indeed, stimulus intensity has been found to affect the primary

reinforcing function of visual stimulus reinforcers on FR 5 schedules of reinforcement (Stewart,

1960), with lights of stronger intensity maintaining a greater number of responses. Furthermore,

in the current study not only were sessions conducted during the light cycle but subj ects were

also fed during the light cycle. Palmatier et al. conducted sessions and fed subj ects during the

dark cycle. Rearing conditions (light or dark) have been shown to influence the reinforcing

effects of turning on and off houselights (Roberts, Marx, Collier, 1958).


It is important to note, however, that the effects of nicotine were not identical across the

two stimulus types, as indicated by the time-course analyses in Figure 3-5. Although nicotine

produced a peak in responding in the second 2 min block for both the Lights On and the Lights

Off phase, the nicotine-induced increases in responding diminished to a greater extent

throughout the remainder of the Lights On session relative to the Lights Off session. Palmatier at

al. (2007) did not begin experimental sessions until 5 min after the nicotine inj section was

administered, whereas in Experiment 2 sessions began immediately after nicotine administration.

Although not statistically significant, there were slight increases in responding in the group of









rats who turned on the stimulus lights in the Palmatier et al. study. This procedural difference

may also account for some of the differences between the current study and that of Palmatier et

al. (2007); however, in Experiment 2 there were still significant increases in responding to turn

on the lights when nicotine was delivered, even when the first five minutes were omitted from

the analyses.


At least two hypotheses have been offered regarding why turning on and turning off

visual stimuli might function as primary reinforcers: (1) curiosity, exploration, or novelty and (2)

stimulus change (Kish, 1966). If the visual stimuli used in Experiment 2 maintained responding

because of curiosity, exploration, or novelty, then with extended exposure responding maintained

by such stimuli should have decreased. Instead responding was sustained over dozens of

sessions, and in some cases even increased over time. Thus, a stimulus change hypothesis is

more consistent with the results of Experiment 2, especially because responding during the lights

on and lights off phases were comparable.

Ultimate explanations regarding why a particular consequence serves as a reinforcer are

not typically addressed by behavior analysts; however, speculations regarding why visual

stimulus change might function as a reinforcer can be made. It is possible that stimulus change in

general corresponds with an increase in access to reinforcement. In the past, rats for which

stimulus change functioned as a reinforcer may have been more likely to survive. In other words,

the reinforcing effects of visual stimulus change may be due to phylogeny behavior that occurs

because of the natural selection history of the species (Skinner, 1969).












Table 3-1. Proportion of responses on the active lever

Lights On


Subj ect

R251

R252

R253

R254

R255

R256

R257

R258


Shaping Baseline 1

--0.93 + 0.02

.46 + 0.02 0.93 + 0.02

.47 + 0. 11 0.91 + 0.03

--0.93 + 0.01

--1.00 + 0.00

.60 + 0.01 0.94 + 0.02

.82 + 0. 13 0.77 + 0.05

--0.92 + 0.02


Nicotine 1

0.93 + 0.01

0.88 + 0.02

0.98 + 0.01

0.97 + 0.01

0.98 + 0.01

0.93 + 0.01

0.96 + 0.04

0.96 + 0.01


Baseline 2

0.93 + 0.02

0.93 + 0.02

0.97 + 0.03

0.95 + 0.01

0.94 + 0.04

0.96 + 0.02

0.85 + 0.01

0.90 + 0.03


Lights Off



0.97 + 0.01

1.00 + 0.01

0.91 + 0.02

0.98 + 0.01

0.97 + 0.01

1.00 + 0.00

0.96 + 0.01


Nicotine 2

0.94 + 0.01

0.90 + 0.01

0.98 + 0.01

0.98 + 0.01

0.95 + 0.01

0.95 + 0.02

0.70 + 0. 12

0.97 + 0.01


Baseline 3 Vehicle

0.96 + 0.01 0.98 + 0.01





0.97 + 0.01 0.93 + 0.01

1.00 + 0.00 0.97 + 0.02






0.96 + 0.01 0.94 + 0.02


0

0


0

0


R251

R252

R253

R254

R255

R256

R257

R258


0.38 + 0. 11 0.92 + 0.02

--0.83 + 0.04

--0.91 + 0.01

0.72 + 0. 12 0.77 + 0.04

0.40 + 0.02 0.64 + 0. 11

--0.96 + 0.01

1.00 + 0.00 1.00 + 0.00

0.87 + 0.05 0.81 + 0.05


0.88 + 0.01

0.90 + 0.02

0.99 + 0.01

0.92 + 0.01

0.96 + 0.01

0.98 + 0.01

1.00 + 0.00

0.95 + 0.01


--9 01

0.98 + 0.01

0.99 + 0.01

0.99 + 0.01

0.99 + 0.01



1.00 + 0.00

0.97 + 0.02


--9 --.1097+00

0.97 + 0.01 0.97 + 0.01




0.98 + 0.01 0.99 + 0.01





0.99 + 0.01 0.99 + 0.01











Table 3-2. Proportion of stimulus presentations during which a response was made


Lights On

Subj ect Baseline 1 Nicotine 1 Baseline 2 Nicotine 2 Baseline 3 Vehicle
R251 0.52 + 0.07 0.45 + 0.06 0.58 + 0.08 0.63 + 0.02 0.66 + 0.07 0.65 + 0.03
R252 0.13 + 0.02 0.37 + 0.04 0.31 + 0.06 0.34 + 0.05---

R253 0.15 + 0.07 0.10 + 0.02 0.20 + 0.04 0.18 + 0.05---

R254 0.23 + 0.08 0.28 + 0.05 0.28 + 0.04 0.30 + 0.02 0.22 + 0.02 0.32 + 0.07

R255 0.13 + 0.10 0.20 + 0.02 0.44 + 0.20 0.28 + 0.02 0.34 + 0.20 0.30 + 0.20

R256 0.41 + 0.10 0.38 + 0.03 0.37 + 0.07 0.47 + 0.09---

R257 0.00 + 0.00 0.00 + 0.00 No stimuli No stimuli---

R258 0.34 + 0.10 0.37 + 0.03 0.36 + 0.04 0.34 + 0.04 0.21 + 0.06 0.30 + 0.08


Lights Off
R251 0.45 + .05 0.55 + 0.06------

R252 0.06 + 0.06 0.20 + 0.04 0.38 + 0.07 0.27 + 0.03 0.27 + 0.03 0.29 + 0.04

R253 0.30 + 0.09 0.38 + 0.06 0.25 + 0.02 0.29 + 0.03 0.28 + 0.03 0.27 + 0.04

R254 0.28 + 0.10 0.50 + 0.06 0.39 + 0.02 0.33 + 0.03---

R255 No stimuli 0.46 + 0.02 0.46 + 0.01 0.40 + 0.02---

R256 0.20 + 0.04 0.28 + 0.02 0.23 + 0.06 0.41 + 0.01 0.30 + 0.04 0.39 + 0.05

R257 0.08 + 0.07 0.14 + 0.10 0.13 + 0.10 0.34 + 0.07 0.57 + 0.20 0.18 + 0.10

R258 0.42 + 0.10 0.58 + 0.04 0.35 + 0.05 0.34 + 0.02---









Table 3-3. Fitted parameter values and corresponding r2 for each linear regression applied to the
rate-dependent graphs shown in Figure 3-6.
Phase Lever Slope y-intercept r2
Both -68 374 0.006
Active* -252 576 0.08
Lights On
Inactive* -4020 527 0.11


Both -97 559 0.007
Lights Off Active* -486 1223 0.12
Inactive* -1494 374 0.08


Note: Asterisks denote slopes that were significantly different from zero.
Lights On: Active F (1,78) = 6.42; Inactive F (1,73) = 9.02
Lights Offi Active F (1,73) = 10.34; Inactive F (1,63) = 5.76













Ligh
Two-Lever Group
30Base Nic Base Nic Base Veh
250 R251 ~ 1~
200



15010 h id i/ t


200

10R255 I:


100


50

0~


One-Lever Group
50 Base Nic Base Nic Base Veh

50400 R254


1001


R258


200

100 ~
0H


500
Nic Base Nic Base
400 -1R256


Nic Base Nic


Base
R252


150
loo
50
0 I c


- 200

100

1_3O 0 g,


~t~,


R257


lean (+ SEM)


100 L(

Two-Lever M


250 i


,,, One-Lever Mean (+ SEM)


Session


SActive
SInactive


Figure 3-1.Total Responses during Lights On. Shown are total responses per 60 min for the last five
sessions of each condition. The left column shows data from subjects in the Two-Lever
training group and the right column shows those from the One-Lever training group. The
bottom row shows the mean (+SEM) for each group. Filled circles represent responding on
the active lever and open circles represent responding on the inactive lever. Note the
different y-axes for each subject. Base = baseline, Nic = Nicotine, Veh = Vehicle.


10 5








Lights Off
One-Lever Group
500
Base Nic Base Nc
400 R254/


Two-Lever Group
Nic Base Nic


300 R5Bs
250R21


-U,


20 /


500


Y


R258


R255


200


et'l


it /~f
Y
~
30O 1 ~o~Yt~4~i~L~


I~P
~2
o


350


Base Nic
R252


Base Nic Base


Vh 500

400


Base Nic Base Nc Base
R256


50

j00


S3(
2r
2


300 j


)O ~~ I=:~ r
jo 100 ~ 1
o ~~3~~V~a~~L O ~b~3~


One-Lever Mean (+ SEM)


40

400 400
30030


Session
SActive
SInactive

Figure 3-2. Total Responses during Lights Off. Shown are total responses per 60 min for the last five
sessions of each condition. The left column shows data from subjects in the Two-Lever
training group and the right column shows those from the One-Lever training group. The
bottom row shows the mean (+SEM) for each group. Filled circles represent responding on
the active lever and open circles represent responding on the inactive lever. Note the different
y-axes for each subject. Base = baseline, Nic = Nicotine, Veh = Vehicle.


~?M:








Lights On


Two-Lever Group
R252


One-Lever Group
R258


'II 1 .1.1..
1 1 I I I" I" "" "" "" "


iI _1'-


..L. I I


..I I II I I, I
I Ir I



I I I-~ 1


11 II1


I


Nicotine






. I II I


Minutes


la'. ha ul


Minutes


Figure 3-3. Cumulative Response Records during Lights On. Shown is the last session of each
condition for two representative subj ects from each group (R252 & R258).
Deflections in the record indicate stimulus presentations -- the pen was reset back to
zero at the end of each 10 sec stimulus. Responses after the deflection and above the


.I


II II


: I
.s ,,~,








horizontal dotted line, but before the pen reset, occurred during the stimulus
presentation.


Lights Off


Two-Lever Group
R252


One-Lever Group
R258


I


Ir I


Nicotine


:I I I 1 I I I lll I II-1, c r


li 1 1 .1


Vehicle


)III~I '


Minutes
Figure 3-4. Cumulative Response Records during Lights Off. Shown is the last session of each condition
of the Lights Off phase for two representative subjects from each group (R252 & R25 8).
Deflections in the record indicate stimulus presentations -- the pen was reset back to zero at


I ll I I I II~ I :Il I I I II I I


I I I I m I~a Ir Il l la



1. .il l .





Minutes


|I | II


j


































I I I I I I


the end of each 10 sec stimulus. Responses after the deflection and above the horizontal
dotted line, but before the pen reset, occurred during the stimulus presentation. Note the
higher y-axis for the bottom three records of subject R258.


Lights Off


Lights On


SB slne
--4- Vehicle


14- Active Lever


Inactive Lever


5 10 15 20 25 30 0 5 10 15 20 25 30

2 min bin


Figure 3-5. Within-SessionTime Course Analyses. Mean + SEM number of responses per 2 min
bin during the 60 min session. The left column shows active (top row) and inactive
(bottom row) responding during the Lights On phase, while the right column shows
responding during the Lights Off phase. Each data path within a panel corresponds
with a different condition: first baseline (filled circles), first nicotine (open circles),
second baseline (filled triangles), second nicotine (open triangles), third baseline
(gray stars), vehicle (open stars). Note the different y-axes for active and inactive
responses.



















Lights Off


Lights On


10000


1000 -


100 -


10 -


1
0.001


0.01

Active Lever
Inactive Lever


0.1 1 10 0.001 0.C

Pre-Drug (log scale)


0 8





0.1 1 10


Figure 3-6. Rate-dependent scatterplots. Rate-dependent scatter plots for the Lights On (left
column) and Lights Off (right column) phases of the experiment. Shown are the log
percentages of pre-drug response rates plotted as a function of log pre-drug response
rates. Response rates on both the active (filled circles) and inactive (open circles)
levers are shown together on each plot.


- -









CHAPTER 4
General Discussion
Mechanisms of Action

Behavioral Mechanisms

Nicotine as a motivating establishing operation. Thus far, the behavioral mechanism of

action implicated by researchers investigating the effects of nicotine on reinforced responding is

that it serves as a motivating establishing operation (MEO). In other words, it serves to enhance

the reinforcing value of certain environmental consequences (Chaudhri et al. 2006; Olausson,

Jentsch, Taylor, 2004a, b; Palmatier et al, 2007, Xiu et al., 2007; Raiff & Dallery, 2006). With

an observing response procedure, Experiment 1 used a group design to show that nicotine

increased responding maintained by conditioned reinforcers, but did not cause a general increase

in behavior. Experiment 2 demonstrated that turning on and turning off a houselight functioned

as moderately effective primary reinforcers for rats and that nicotine selectively increased

responding maintained by such consequences. The results of Experiments 1 and 2 are consistent

with a MEO account of nicotine-induced increases in responding.

It is interesting that the MEO effects of nicotine were relatively specific to responding

maintained by the conditioned reinforcing visual stimuli in Experiment 1. One might also have

expected food-maintained responding in Experiment 1 to increase (i.e., food-extinction responses

in the presence of the S+), but no such increases were noted. Although it is possible that the lack

of effect was simply due to a ceiling effect, there are a few other possibilities that should be

considered. First, it may be the case that nicotine selectively increased moderately reinforcing

stimuli, as others have suggested (Palmatier et al., 2007). However, there have been other

demonstrations of nicotine increasing responding maintained by more potent reinforcers, such as

liquid sucrose (Jias & Ellison, 1990), cocaine (Bechtholt & Mark, 2002; McQuown, Belluzi,

Leslie, 2007), and alcohol (Clark, Lindgren, Brooks, Watson, Little, 2001; L6, Wang, Harding,










Juzytsch, Shaham, 2003; Smith, Horan, Gaskin, Amit, 1999). In a previous study conducted in

our lab, responding maintained by food was increased after chronic nicotine administration

(Raiff & Dallery, 2006). There were a number of procedural differences between the current

study and the other studies in which nicotine increased responding maintained by more potent

primary reinforcers, and thus it is possible that there are specific conditions under which nicotine

will serve as a MEO for such consequences. It is also possible that the effects of nicotine on the

more potent reinforcers listed above were due to a different behavioral or biological mechanism

of action. At this time, however, the MEO role for nicotine provides the most cohesive account

with respect to the current data and those listed above.


One potential disadvantage of adopting the motivating operation account is that it could

be used as a hypothetical construct. The term motivating operation is currently used as a

summary term, or an intervening variable. In other words, it refers to a group of environmental

variables that is related to behavior, but is completely anchored in observable events

(MacCorquodale & Meehl, 1948; Mazur, 2005). For instance, motivating operations could refer

to deprivation procedures, satiation procedures, or introduction of some environmental event,

like nicotine. All of these manipulations correspond with a concomitant change in behavior

(either becoming more or less likely) and are all considered motivating operations. The changes

in behavior do not depend in any way on the term motivating operation, but instead on the

environmental manipulations which the term summarizes. Even if the term were abandoned, the

phenomena would continue to exist.

The concern is if the term motivating operation drifts from an intervening variable to a

hypothetical construct. A hypothetical construct is an actual entity that is thought to exist

independent of the observations that led to its identification. These entities are used to explain









the very phenomena that led to their presumed existence (MacCorquodale & Meehl, 1948). In

fact, the term motivation has been used to refer to something an individual has or something

within an individual (Patall, Cooper, Robinson, 2008). Skinner (1953, pg 31) warned that, "..

such terms as 'hunger,' 'habit,' and 'intelligence' convert essentially the properties of a process

or relation into what appear to be things." Using motivating operations as hypothetical

constructs would be dangerous because they could lead to circular explanations, thereby

preventing a more detailed investigation into the environmental determinants of behavior

(Skinner, 1953).

As long as the term remains an intervening variable, it carries with it a number of

advantages. At the most basic level, adopting the term MEO in behavioral pharmacology would

make the discipline more conceptually systematic with behavior analysis, from which it has

already adopted a number of concepts and procedures (Baer, Wolf, Risley, 1968; Thompson &

Schuster, 1968). MEOs have been critically important to behavior analysts' understanding of

reinforcement, and thus the concept could bear great benefits for behavioral pharmacologists as

well. Without the concept of motivating operations, the dynamic nature of a stimulus' ability to

function as a reinforcer would be perplexing.

Furthermore, adopting the concept of motivating operations could tie together a number

of seemingly disparate areas in behavioral pharmacology. Because drugs have been

conceptualized as reinforcers, various treatment manipulations could be conceptualized in terms

of motivating operations. For instance, as described in the General Introduction, nicotine is the

primary constituent in tobacco thought to be responsible for smoking maintenance the

assumption being that nicotine serves as a primary reinforcer. Nicotine replacement therapies

(NRT), such as the patch or gum, are widely available and are marketed as reducing smoking-









abstinence-induced cravings (Shiffman, Ferguson, Gwaltney, Balabanis, Shadel, 2006;Teneggi,

Tiffany, Squassante, Milleri, Ziviani, Bye, 2002). Thus, NRT products could be conceptualized

as motivating abolishing operations in that they decrease the reinforcing aspects of using tobacco

products. Pharmacological agents used to treat other drugs of abuse are also thought to function

in a similar manner, such as methadone maintenance for opioid dependence (Donny, Brasser,

Bigelow, Stitzer, Walsh, 2005). In addition to drug abuse treatment, other research areas in

behavioral pharmacology that might be linked by, or benefit from, the notion of motivating

operations are self-administration (Haney & Spealman, 2008; Woolverton, Wang, Vasterling,

Carroll, Tallarida, 2008), priming (de Wit, 1996; James-Walke, Williams, Taylor, & McMillan,

2007), reinstatement (Bongiovonni & See, 2008; Liu, Caggiula, Nobuta, Poland, Pechnick,

2006), sensitization to the reinforcing effects of drugs (Liu, Roberts, Morgan, 2005; Ward, Lack,

Morgan, Roberts, 2006) and drug interactions (Tanda & Goldberg, 2000; Ward, Lack, Morgan,

Roberts, 2006).

Specifically related to nicotine, the MEO account has more immediate and obvious

benefits in that it can account for extant data on the reinforcer-enhancing effects of nicotine and

it may lead to novel experiments. For instance, the definition of a MEO specifies that it leads to

an increase in the probability of all responses which have led to the reinforcer in the past.

However, the appropriate discriminative stimuli must also be present if the response is to occur,

regardless of whether the motivating operation is in place (Michael, 1982). One experiment

might consist of training a few different responses that all have the same outcome, but that are

trained in the context of a multiple schedule, and thus the different responses occur in the

presence of different discriminative stimuli (e.g., lever press, nose poke, chain pull). If nicotine

increases the motivating operation for the consequence in question, then only the response










appropriate to each discriminative stimulus should increase, whereas the other responses should

remain unchanged. Furthermore, the different response topographies could generate different

rates of responding, even within the same organism. These differences in rate of responding

would not be expected to affect the outcomes if nicotine does in fact serve as a MEO. Such a

procedure might be able to address the rate-dependent tendencies of nicotine that were found in

Experiments 1 and 2.

Other future directions, mentioned earlier, include determining the conditions under

which nicotine serves as a MEO for different consequences. Consider the example of food

deprivation as a MEO given in the General Introduction. Food deprivation will not increase the

value of all reinforcers; it is specific to food consequences. It may be that nicotine is a MEO for

some reinforcers but not others, as the results from Experiment 1 suggested. Most of the

research demonstrating the MEO role of nicotine has used visual stimulus reinforcers; therefore,

it will be necessary to determine whether responding maintained by reinforcers in other sensory

modalities (e.g., auditory, olfactory) are also increased by nicotine administration. Furthermore,

it is not clear how nicotine might influence responding maintained or suppressed by different

behavioral processes, such as negative reinforcement or punishment. Exploring the scope of

nicotine as a MEO is an important task if the concept is to have predictive utility.


Other behavioral accounts. Before accepting the MEO account for nicotine-induced

increases in responding, it is necessary to rule out other behavioral accounts. Two such accounts

were addressed in Experiments 1 and 2: (1) general increases in behavior and (2) rate-

dependence. To investigate whether nicotine caused general increases in behavior, Experiment 1

showed that responding did not reliably increase during an extinction component, while










Experiment 2 showed that nicotine only increased responding on an active lever, even in subjects

who were initially trained to press both the active and inactive levers.

The rate-dependent analyses from Experiments 1 and 2 indicated that there was a

tendency for nicotine to increase low pre-drug response rates and to decrease high pre-drug

response rates. Although there were significant negative slopes, the percentage of variance

accounted for was always low, never exceeding 21%, which suggests that the relationship

between pre-drug and drug response rates is not very well described by a linear function. Thus,

the present studies provided weak evidence that nicotine has rate-dependent effects.

Even if the rate-dependent effects were more robust, such a finding would only indicate a

relationship between two dependent variables (i.e., pre-drug response rates and drug response

rates), but would not specify a behavioral or biological mechanism of action, such as changes in

stimulus control, motoric capabilities, or motivating operations (Branch, 1984; Odum, Lieving,

Schaal, 2002). Thus, a rate-dependent relationship does not rule out the possibility that changes

in responding were a function of nicotine serving as a MEO. More work will be necessary to test

whether nicotine merely increases low rates of responding, or whether such increases are specific

to parameters of the reinforcing stimuli (Lamb & Ginsburg, 2008). A recent study showed that

nicotine also increased the number of completed ratios on a progressive ratio schedule of visual

stimulus presentation (Chaudhri et al., 2007), suggesting that nicotine does more than merely

increase response rates. However, future studies should be aimed at teasing apart the importance

of response rates on the effects of nicotine administration.


Neurobiological Mechanisms

In addition to the behavioral mechanisms of action just described, researchers have

investigated corresponding neurobiological mechanisms that might be relevant to the results seen









in Experiments 1 and 2. Although research in this area is extensive, only a brief overview of the

findings that seem particularly relevant to the current studies will be addressed.

Similar to other drugs of abuse, nicotine administration results in the release of dopamine

(DA) in the mesolimbic system, which is comprised of the ventral tegmental area (VTA) and the

nucleus accumbens (NAc), among other structures (Wonnacott, Sidhpura, Balfour, 2005). The

NAc can be further divided into two distinct sections the core and the shell. Recently, the core

and shell have been found to contribute in different ways to drug self-administration. Ito,

Robbins and Everitt (2004) compared the effects of NAc core and shell lesions on cocaine self-

administration, using a standard self-administration procedure and a second-order schedule of

self-administration. Second-order schedules are sometimes used to study conditioned

reinforcement. The standard procedure consisted of a FR1 schedule of cocaine infusions paired

with a 20 s blackout and illumination of a stimulus light. The second-order schedule consisted of

a FR 10 schedule of stimulus light illumination, such that every 10th stimulus was paired with a

cocaine infusion and 20 s blackout (FR10 [FR10:S]). There were no differences in cocaine self-

administration in core- and shell-lesioned rats when the standard procedure was used. However,

when the second-order schedule was employed, fewer core-lesioned rats met the self-

administration criterion and those who did meet the criterion made significantly fewer responses

than rats in the shell-lesioned and control groups. Furthermore, core-lesioned and control

subj ects showed a significant increase in response rates after the first cocaine infusion in the

second-order schedule, whereas shell-lesioned subjects did not. The authors concluded that, "The

core seems to mediate control by conditioned reinforcers, whereas the shell seems to mediate the

potentiation of that control by cocaine, perhaps reflecting stimulant or motivational effects of the

drug." In other words, although not distinguished in their paper, the authors suggested that the









NAc shell may be related to general increases in behavior induced by cocaine or to the MEO

effects of cocaine on sensory reinforcers. Although they attributed conditioned reinforcing

properties to the visual stimuli used in their study, it is not clear whether the stimuli were

actually primary reinforcers, as the results from the present Experiment 2 might suggest.

Nevertheless, their findings are directly related to the current experiments in that increased DA

activity in the NAc core and shell may differentially influence sensory and/or conditioned

reinforcers.

The implications of nicotine-induced DA release in the NAc have also been addressed by

a number of researchers, and Balfour (2004) recently proposed a theory that directly relates to

the MEO mechanism of nicotine outlined above. Balfour was particularly interested in

addressing how nicotine could maintain tobacco use, even if nicotine itself did not function as a

primary reinforcer. He suggested that nicotine-induced DA release in the NAc core makes it

possible for nicotine-associated environmental stimuli to become conditioned reinforcers.

Furthermore, Balfour suggested that nicotine-induced DA release in the NAc shell further

potentiates, or serves as a MEO, for those associated stimuli. Thus, Balfour suggested that the

NAc core and shell each contribute to nicotine self-administration, or tobacco use, by

establishing and increasing the reinforcing properties of tobacco-related stimuli. It might be

useful to use the procedures described in Experiments 1 and 2 to further explore this possible

neurobiological mechanism of action.

Concluding Remarks

Given the weak primary reinforcing effects of nicotine, as evidenced by the difficulties in

establishing nicotine self-administration with nonhumans, the popularity and success of smoking

and tobacco use in humans is surprising. Thus, we return to the original question: what has made

tobacco such a successful commodity? The current findings support a MEO role for nicotine,









which may account for the prevalence of smoking and the difficulty smokers have in quitting. If

nicotine enhances the reinforcing value of other environmental consequences, then quitting

would not only result in a loss of cigarette reinforcers, but also a loss in the value of alternative

reinforcers that were enhanced by nicotine.










LIST OF REFERENCES


Baer, D. M., Wolf, M. M, & Risley, T. R. (1968). Some current dimensions of applied behavior
analysis. Journal ofApplied Behavior Analysis, 1, 91-97.

Balfour, D.J.K. (2004). The neurobiology of tobacco dependence: A preclinical perspective on
the role of the dopamine proj sections to the nucleus. Nicotine & Tobacco Research, 6,
899-912.

Baum, W.M. (1973) .The correlation-based law of effect. Journal of the ExperintentalIAnalysis
ofBehavior, 20, 137-153.

Bechtholt, A.J. ,Mark, G.P. (2002). Enhancement of cocaine-seeking behavior by
repeated nicotine exposure in rats. Psychopharnzacology, 162, 178-185.

Berlyne, D.E. (1957). Uncertainty and conflict: a point of contact between information theory
and behavior theory concepts. Psychological Review, 64, 329-333.

Bongiovanni, M. & See, R.E. (2008). A comparison of the effects of different operant training
experiences and dietary restriction on the reinstatement of cocaine-seeking in rats.
Pharmacology, Biochentistry and Behavior, 89, 227-233.

Branch, M.N. (1984). Rate dependency, behavioral mechanisms, and behavioral pharmacology.
Journal of the Experimental Analysis ofBehavior, 42, 5 1 1-522.

Branch, M. N. (2006). How research in behavioral pharmacology informs behavioral science.
Journal of the Experimental Analysis ofBehavior, 85, 407-423.

Caggiula, A.R., Donny, E.C., Chaudhri, N., Perkins, K.A., Evans-Martin, F.F., Sved,
A.F. (2002a). Importance of nonpharmacological factors in nicotine self-administration.
Physiolological Behavior, 77, 683-687.

Caggiula, A.R., Donny, E.C., White, A.R., Chaudhri, N., Booth, S., Gharib, M.A.,
Hoffman, A., Perkins, K.A., & Sved, A.F. (2001). Cue dependency of nicotine self-
administration and smoking. Pharmacology, Biochentistly, and Behavior, 70, 515-530.

Caggiula, A.R., Donny, E.C., White, A.R., Chaudhri, N., Booth, S., Gharib, M.A.,
Hoffman, A., Perkins, K.A., & Sved, A.F. (2002b). Environmental stimuli promote
acquisition of nicotine self-administration in rats. Psychopharnzacology, 163, 230-237.

Carlton, PL (1983). A Printer ofBehavioral Pharmacology. New York: W. H. Freeman
& Co.

Carmody T.P. (1992). Preventing relapse in the treatment of nicotine addiction: current issues
and future directions. Journal ofPsychoactive Drugs, 24, 13 1-158.










Case, D.A. & Fantino, E. (1981). The delay-reduction hypothesis of conditioned reinforcement
and punishment: Observing behavior. Journal of the Experimental Analysis ofBehavior,
35, 93-108.

Centers for Disease Control and Prevention (2005). Annual Smoking-Attributable Mortality,
Years of Potential Life Lost, and Productivity Losses--United States, 1997-2001.
M~orbidity and Mortality Weekly Report, 54, 625-628.
Available at: http ://www.cdc.gov/mmwr/preview/mmwrhtml/mm542a.htm

Centers for Disease Control and Prevention (2006). History of the Surgeon General's Report on
Smoking and Health. Last updated 2/28/07 Available at:
http://www. cdc. gov/tob acco/data~stati sti cs/sgr/hi story.htm

Centers for Disease Control and Prevention (2007). Cigarette Smoking Among Adults--United
States, 2006. M~orbidity and Mortality Weekly Report, 56, 1157-1161
Available from: http://www. cdc.gov/mmwr/previ ew/mmwrhtml/mm 5644a2.htm

Chaudhri, N., Caggiula, A.R., Donny, E.C., Booth, S. Gharib, S., Craven, R., Allen, S.S.,
Sved, A.F., Perkins, K.A. (2005). Sex differences in the contribution of nicotine and
nonpharmacological stimuli to nicotine self-administration in rats. Psychopharmacology,
180, 258-266.

Chaudhri, N., Caggiula, A.R., Donny, E.C., Booth, S. Gharib, S., Craven, R., Palmatier,
M.I., Liu, X., Sved, A.F. (2006). Operant responding for conditioned and unconditioned
reinforcers in rats is differentially enhanced by the primary reinforcement and
reinforcement-enhancing effects of nicotine. Psychopharmacology, 189, 27-36.

Chaudhri, N., Caggiula, A.R., Donny, E.C., Booth, S., Gharib, M., Craven, L., Palmatier,
M.I., Liu, X., Sved, A.F. (2007). Self-administered and noncontingent nicotine enhance
reinforced operant responding in rats: Impact of nicotine dose and reinforcement
schedule. Psychopharmacology, 190, 353-362.

Clark, A., Lindgren, S., Brooks, S.P., Watson, W.P., Little, H.J. (2001). Chronic infusion of
nicotine can increase operant self-administration of alcohol. Neuropharmacology, 41,
108-117.

Cohen, C., Perrault, G., Griebel, G., Soubrie, P. (2005). Nicotine-associated cues
maintain nicotine-seeking behavior in rats several weeks after nicotine withdrawal:
Reversal by the cannabinoid (CBl1) receptor antagonist, rimonabant (SR141716).
Neuropsychopharmacology, 30, 145-155.

Cohen, S.L., Riley, D.S., Weigle, P.A. (1993). Tests of behavioral momentum in simple and
Multiple schedules with rats and pigeons. Journal of the Experimental Analysis of
Behavior, 60, 255-291.










Cooper, M.A. (2004). Tobacco industry: do ads and new products still target teen smokers? CQ
Researcher, 14, 1025-1049.

Cooper, J.O., Heron, T.E., Heward, W.L. (2007). Applied Behavior Analysis. Upper Saddle
River, NJ: Pearson Education, Inc.

Corrigall, W.A. & Coen, K.M. (1989). Nicotine maintains robust self-administration in rats on a
limited-access schedule. Psychopharmacology, 99, 473-478.

Dallery, J., Houtsmuller, E. J., Pickworth, W. B., & Stitzer, M. (2003). Effects of cigarette
nicotine content and smoking pace on subsequent craving and smoking.
Psychopharmacology, 165, 172-180.

Dar, R. & Frenk, H. (2002a). Nicotine addiction: fact or theory? Addiction
Research and Theory, 10, 219-224.

Dar, R. & Frenk, H. (2002b). Nicotine self-administration in animals: a reevaluation. Addiction
Research and Theory, 10, 545-579.

Dar, R. & Frenk, H. (2004). Smokers do not self-administer nicotine other than in tobacco: a
reply to Perkins (2004). Psychopharmacology, 175, 259-261.

Dar, R. & Frenk, H. (2005). Nicotine may reinforce intravenous drug-taking in drug users: a
comment on Harvey et al.. Psychopharmacology, 179, 516-517.

Davison, M. & Baum, W.M. (2007). Do conditional reinforcers count? Journal of the
ExperimentalAnalysis ofBehavior, 86, 269-283.

Denoble, V.J. & Mele, P.C. (2006). Intravenous nicotine self-administration in rats: effects of
mecamylamine, hexamethonium and naloxone. Psychopharmacology (Berl), 184, 266-
72.

de Wit, H. (1996). Priming effects with drugs and other reinforcers. Experimental and Clinical
Psychopharmacology, 4, 5-10.

Dews, P. B. (1955). Studies on behavior. I. Differential sensitivity to pentobarbital of pecking
performance in pigeons depending on schedule of reward. Journal of Pharmacology of
Experimental. Therapeutics, 113, 393-401.

Dicesare, A.. McAdam, D.B Toner, A., Varrell, J. (2005). The effects of
methylphenidate on a functional analysis of disruptive behavior: A replication and
extension. Journal ofApplied Behavior Analysis, 38, 125-128.

Dinsmoor, J.A. (1983). Observing and conditioned reinforcement. Behavioral andBrain
Sciences, 6, 693-728.










Dinsmoor, J.A., Brown, M.P., Lawrence, C.E. (1972). A test of the negative discriminative
stimulus as a reinforcer of observing. Journal of the Experimental Analysis ofBehavior,
18, 79-85.

Dols, M., Willems, B., & van den Hout, M. (2000). Smokers can learn to influence their urge to
smoke. Addictive Behaviors, 25, 103-108.

Donny, E.C., Brasser, S.M., Bigelow, G.E., Stitzer, M.L., Walsh, S.L. (2005). Methadone doses
of 100 mg or greater are more effective than lower doses at suppressing heroin self-
administration in opioid-dependent volunteers. Addiction, 100, 1496-1509.

Donny, E.C, Chaudhri, N., Caggiula, A.R., Evans-Martin, F.F., Booth, S., Gharib, S.,
Clements, L.A., Sved, A.F. (2003). Operant responding for a visual reinforcer in rats is
enhanced by noncontingent nicotine: implications for nicotine self-administration and
reinforcement. Psychopharmacology, 169, 68-76.

Dwoskin, L.P., Crooks, P.A., Teng, L., Green, T.A., Bardo, M.T. (1999). Acute and
chronic effects of nornicotine on locomotor activity in rats: altered response to nicotine.
Psychopharmacology, 145, 442-451.

Fantino, E. (1977). Conditioned reinforcement: Choice and information. In Honig, W.K. &
Staddon, J.E.R. (eds) H~andbook of Operant Behavior (pp 3 13-337). Englewood Cliffs,
N.J.: Prentice-Hall.

Faraday, M.M, Elliott, B.M, Phillips, J.M., Grunberg, N.E. (2003). Adolescent and adult
male rats differ in sensitivity to nicotine's activity effect. Pharmacology, Biochemistry,
and Behavior, 74, 917-931.

Federal Trade Commission (2005). Federal Trade Commission Issues Cigarette Report for 2003:
Marketing Expenditures Increased to $15. 15 Billion, the M~ost Ever Reported to the FTC.
Online source: http ://www.ftc.gov/opa/2005/08/cigreport.htm

Field, M., & Duka, T. (2001). Smoking expectancy mediates the conditioned responses to
arbitrary smoking cues. Behavioural Pharmacology, 12, 183-194.

Fleshier, N. & Hoffman, H. (1962). A progression for generating variable interval schedules.
Journal of the Experimental Analysis ofBehavior, 5, 529-530.

Food and Agricultural Organization (2003). Projections of tobacco production, consumption and
tradert~t~rt~t~rt~t~rt~ by 2010. Rome.

Frenk, H. & Dar, R. (2000). A critique of nicotine addiction. New York, NY: Plenum Publishers.

Frenk, H. & Dar, R (2004). Reward potentiation or behavioral activation? A comment on Donny
et al. Psychopharmacology, 171, 472-473.










Gold, M. (1995). Tobacco. Drugs ofAbuse: a comprehensive series for clinicians, 4, 1-211.

Goldberg, S.R., Spealman, R.D., Goldberg, D.M. (1981). Persistent behavior at high
rates maintained by intravenous self-administration of nicotine. Science, 214, 573-575.

Goodrick, C. (1970). Light- and dark-contingent bar pressing in the rat as a function of
age and motivation. Journal of Comparative and Physiological Psychology, 73, 100-
104.

Green, T.A., Cain, M.E., Thompson, M., Bardo, M.T. (2003). Environmental enrichment
decreases nicotine-induced hyperactivity in rats. Psychopharmacology, 170, 23 5-241.

Griffiths, R.R., Wurster, R.M., Brady, J.V. (1981). Choice between food and heroin: effects of
morphine, nalaxone, and secobarbitol. Journal of the Experimental Analysis ofBehavior,
35, 335-351.

Haney, M. & Spealman, R. (2008). Controversies in translational research: drug self
administration. Psychopharmacology, online first.

Harris, A.C., Burroughs, D., Pentel, P.R., LeSage, M.G. (2008). Compensatory nicotine self-
administration in rats during reduced access to nicotine: an animal model of smoking
reduction. Experimental and Clinical Psychopharmacology, 16, 86-97.

Hatch, Jr., C.E. (1942). Tobacco: it's history illustrated by the books, manuscripts and
engravings in the library of George Arents, Jr., by Jerome E. Brooks. William and2\a~ry
College Quarterly Historical Ma'gazine, 22, 101-1 13.

Hendry, D.P. (1969). Introduction. In Hendry (ed) Conditioned Reinforcement. (ppl1-3 3).
Homewood, Il: The Dorsey Press.

Henningfield, J.E. & Zeller, M. (2006). Nicotine psychopharmacology research contributions to
United States and global tobacco regulation: a look back and a look forward.
Psychopharmacology, 184, 286-291.

Huynh, H. & Feldt, L.S. (1976). Estimation of the Box correction for degrees of freedom from
sample data in randomized block and split-plot designs. Journal of Educational
Statatistics, 1, 69-82.

Ito, R., Robbins, T.W., Everitt, B.J. (2004). Differential control over cocaine-seeking
behavior by nucleus accumbens core and shell. Nature Neuroscience, 7, 389-397.

Iwata, B. A., Dorsey, M. F., Slifer, K. J., Bauman, K. E., & Richman, G. S. (1994). Toward
a functional analysis of self-injury. Journal ofAppliedBehavior Analysis, 2 7, 197-209.










Iwata, B. A., Smith, R. G., & Michael, J. L. (2000). Current research on the influence of
establishing operations on behavior in applied settings. Journal ofAppliedBehavior
Analysis, 33, 411-418.

James-Walke NL, Williams HL, Taylor DA, McMillen BA. (2007). Periadolescent nicotine
exposure produces sensitization to reinforcement by diazepam in the rat. Neurotoxicology
and' Teratology, 29, 3 1-36.

Jias, L.M. & Ellison, G. (1990). Chronic nicotine induces a specific appetite for sucrose in rats.
Pharmacology, Biochentistly, and Behavior, 35, 489-491.

Jwaideh, A.R. & Mulvaney, D.E. (1976). Punishment of observing by a stimulus associated
with the lower of two reinforcement frequencies. Learning and2~otivation, 7, 21 1-222.

Kelleher, E. & Gollub, L.R. (1962). A review of positive conditioned reinforcement. Journal of
the Experimental Analysis ofBehavior, 5, 543-597.

Kendall, S. B. (1973). Redundant information in an observing-response procedure. Journal of
the Experimental Analysis ofBehavior, 19, 8 1-92.

Killeen, P.R., Hanson, S.J., Osborne, S.R. (1978). Arousal: genesis and manifestation as
response rate. Psychological Review, 85, 571-58 1.

Kluger, R. (1997). Ashes to ashes: Anzerica's hund'red'-year cigarette war, the public health, and'
The unabasheed triumph of Philip M~orris. New York: Alfred A. Knopf, Inc.

Koehl, M., Bjijou, Y., Le Moal, M., Cador, M. (2000). Nicotine-induced locomotor
activity is increased by preexposure of rats to prenatal stress. Brain Research, 882, 196-
200.

Kosowski, A.R., Liljequist, S. (2005). Behavioural sensitization to nicotine precedes
the onset of nicotine-conditioned locomotor stimulation. Behavior and Brain Research,
156, 11-17.

Lamb, R.J & Ginsburg, B.C. (2008). Reinforcement magnitude modulates the rate-dependent
effects of fluvoxamine and desipramine on fixed interval responding in the pigeon.
Behavioural Pharmacology, 19, 51-60.

Laraway, S, Snycerski, S, Michael, J, Poling, A (2003). Motivating operations and terms to
describe them: some further refinements. Journal of the Experimental Analysis of
Behavior, 36, 407-414.

L6, A.D., Wang, A., Harding, S., Juzytsch W., Shaham, Y. (2003). Nicotine increases alcohol
self-administration and reinstates alcohol seeking in rats. Psychopharnzacology, 168, 216-
221.










Le Foll, R., Wertheim, C., Goldberg, S.A (2007). High reinforcing efficacy of nicotine in non-
human primates. Public Library of Science, 2, 1-9.

Lile, J.A., Nader M.A. (2003). The abuse liability and therapeutic potential of drugs evaluated
for cocaine addiction as predicted by animal models. Current Neuropharnzacology, 1,
21-46

Liu, X., Caggiula, A.R., Yee, S.K., Nobuta, H., Poland, R.E., Pechnick, R.N. (2006).
Reinstatement of nicotine-seeking behavior by drug-associated stimuli after extinction in
rats. Psychopharnzacology, 184, 417-425.

Liu, X., Palmatier, M.I., Caggiula, A.R., Donny, E.C., Sved, A.F. (2007). Reinforcement
enhancing effect of nicotine and its attenuation by nicotinic antagonists in rats.
Psychopharnzacology, 194, 463-473.

Liu, Y., Roberts, D.C.S., Morgan, D. (2005). Sensitization of the reinforcing effects of self
administered cocaine in rats: effects of dose and intravenous inj section speed. European
Journal ofNeuroscience, 22, 195-200.

Lubow, R.E. & Moore, A.U. (1959). Latent inhibition: the effect of nonreinforced pre-exposure
to the conditional stimulus. Journal of Comparative and Physiological Psychology, 52,
415-419.

Lucki, I. (1983). Rate-dependent effects of amphetamine on responding under random-interval
schedules of reinforcement in the rat. Pharmacology, Biochentistly, and Beehavior, 18,
195-201.

MacCorquodale, K. & Meehl, P.E. (1948). On a distinction between hypothetical constructs and
intervening variables. Psychological Review, 55, 95-107.

Marx, M.H., Henderson, R.L., & Roberts, C.L. (1955). Positive reinforcement of the bar
pressing response by a light stimulus following dark operant protests with no afteraffect.
Journal of Comparative and Physiological Psychology, 48, 73-76.

Mazur, J.E. (2005). Learning and Behavior 6 E. Upper Saddle River, NJ: Prentice Hall.

McAdam, D.B. Klatt, K.P., Koffarnus, M., Dicesare, A., Solberg,K. Welch, C.,Murphy, S.
(2005). The effects of establishing operations on preferences for tangible items. Journal
ofApplieadBehavior Analysis, 38, 107-1 10.

McComas, J., Hoch, H., Paone, D., & El-Roy, D. (2000). Escape behavior during academic
tasks: A preliminary analysis of idiosyncratic establishing operations. Journal of Applied
Behavior Analysis, 33, 479-493.

McQuown, S.C., Belluzi, J.D., Leslie, F.M. (2007). Low dose nicotine treatment during early
adolescence increases subsequent cocaine reward. Neurotoxicology and' Teratology, 29, 66-
73.










McKim, W.A. (1997). Drugs and behavior: an introduction to behaviora.lpha.rmacology (3rd)
Upper Saddle River, NJ: Prentice Hall, Inc.

Michael, J. (1982). Distinguishing between discriminative and motivational functions of
stimuli. Journal Experimental Analysis ofBehavior, 37, 149-155.

Michael, J. (1993). Establishing operations. The Behavior Analyst, 16, 191-206.

Michael, J., (2000). Implications and refinements of the establishing operation concept.
Journal ofApplied Behavior Analysis, 33, 401-410.

Negus, S.S. (2006). Choice between heroin and food in nondependent and heroin-dependent
rhesus monkeys: effects of naloxone, buprenorphine, and methadone. Journal of
Pharmacology and Experimental Therapeutics, 31 7, 71 1-723.

Nevin, J.A. (1974). Response strength in multiple schedules. Journal ExperimentalAnalysis of
Behavior, 21, 389-408.

Nevin, J.A. & Grace, R.C. (2000). Behavioral momentum and the Law of Effect. Behavior and
Brain Sciences, 23, 73-130.

Northup, J., Fusilier, I., Swanson, V., Roane, H., & Borrero, J. (1997). An evaluation of
methylphenidate as a potential establishing operation for some common classroom
reinforcers. Journal ofApplied Behavior Analysis, 30, 615-625.

O'Dell, L.E. & Koob, G.F. (2007). 'Nicotine deprivation effect' in rats with intermittent 23-hour
access to intravenous nicotine self-administration. Pharmacology, Biochemistry, and
Behavior, 86, 346-353.

Odum, A.L., Lieving, L.M., Schaal, D.W. (2002). Effects of d-amphetamine in a temporal
discrimination procedure: selective changes in timing or rate dependency? Journal
ExperimentalAnalysis ofBehavior, 78, 195-214.

Olausson, P., Jentsch, J.D., Taylor, J.R. (2004a). Nicotine enhances responding with
conditioned reinforcement. Psychopharmacology, 171, 173-178.

Olausson, P., Jentsch, J.D., Taylor, J.R. (2004b). Repeated nicotine exposure enhances
responding with conditioned reinforcement. Psychopharmacology, 17, 98-104.

Palmatier, M.I., Evans-Martin, F.F., Hoffman, A., Caggiula, A.R, Chaudhri, N, Donny,
E.C, Liu, X., Booth, S. Gharib, S., Craven, R., Sved, A.F. (2006). Dissociating
the primary reinforcing and reinforcement-enhancing effects of nicotine using a rat self-
administration paradigm with concurrently available drug and environmental reinforcers.
Psychopharmacology, 184, 391-400.










Palmatier, M.I, Matteson, G.L., Black, J.J., Liu, X., Caggiula, A.R., Craven, L., Donny, E.C.,
Sved., A.F. (2007). The reinforcement enhancing effects of nicotine depend on the
incentive value of non-drug reinforcers and increase with repeated drug inj sections. Drug
and Alcohol Dependence, 89, 52-59.

Panagis, G., Nisell, M., Nomikos, G.G., Chergui, K., Svensson, T.H. (1996). Nicotine
inj sections into the ventral tegmental area increase locomotion and Fos-like
immunoreactivity in the nucleus accumbens of the rat. Brain Research, 730, 133-142.

Patall, E.A., Cooper, H., Robinson, J.C. (2008). The effects of choice on intrinsic motivation and
related outcomes: a meta-analysis of research findings. Psychological Bulletin, 134, 270-
300.

Perkins, K.A. (1999). Baseline-dependency of nicotine effects: a review. Behavioural
Pharnzacolology, 10, 597-615.

Pickens, R. & Thompson, T. (1968). Cocaine-reinforced behavior in rats: effects of
reinforcement magnitude and fixed ratio size. The Journal ofPharnzacology and
Experimental Therapeutics, 161, 122-129.

Pierce, C.P. & Kumaresan, V. (2006). The mesolimbic dopamine system: The final common
pathway for the reinforcing effect of drugs of abuse? Neuroscience and Biobehavioral
Reviews, 30, 215-238.

Pierce, J.P., Choi, W.S., Gilpin, E.A., Farkas, A.J., Berry, C.C. (1998). Tobacco industry
promotion of cigarettes and adolescent smoking. Journal of the American M~edical
Association, 279, 511-516.

Poling, A. & Byrne, T. (2000). Introduction to behavioralpharmacology. Reno, NV: Context
Press.

Raiff, B.R. & Dallery, J. (2006). Effects of acute and chronic nicotine on responses
maintained by primary and conditioned reinforcers in rats. Experintental and Clinical
Psychopharnzarnacology, 14, 296-305.

Roberts C.L., Marx, M.H., & Collier, G. (1958). Light onset and light offset as reinforcers for the
albino rat. Journal of Comparative and Physiological Psychology, 51, 575-579.

Robinson, J.S. (1959). Light onset and termination as reinforcers for rats living under normal
light conditions. Psycholological Reports, 5, 793-796.

Rose, J. E., Behm, F. M., Westman, E. C., & Johnson, M. (2000). Dissociating nicotine and
nonnicotine components of cigarette smoking. Pharmacology Biochentistry and
Behavior, 67, 71- 8 1.










Rose, J. E., Tashkin, D. P., Ertle, A., Zinser, M. D., & Lafter, R. (1985). Sensory blockade of
smoking satisfaction. Pharmacology, Biochemistry, and Behavior, 23, 289-293.

Russell, M.A.H. (1971). Cigarette smoking: natural history of dependence disorder. British
Journal of2~edical Psychology, 44, 1-16.

Saulsgiver, K.A., McClure, E.A., Wynne, C.D.L. (2007). Effects of amphetamine on differential
reinforcement of low rates of responding. Behavioural Pharmacolacology, 18, 1 19-133.

Schuster, R. H. (1969). A functional analysis of conditioned reinforcement. In Hendry, DP (ed),
Conditioned reinforcement. The Dorsey Press, Homewood, IL, pp 192-23 5.

Segal, E. (1959). Confirmation of a positive relation between deprivation and number of
responses emitted for light reinforcement. Journal of the Experimental Analysis of
Behavior, 2, 165-169.

Shaefer, G.J. & Michael, R.P. (1986). Task-specific effects of nicotine in rats: intracranial self
stimulation and locomotor activity. Neuropharmacology, 25, 125-131.

Shahan, T.A. (2002). Observing responses: effects of rate and magnitude of primary
reinforcement. Journal of the Experimental Analysis of Behavior, 78, 161-178.

Shahan, T.A. (2003). Stimuli produced by observing responses make rats' ethanol self
administration more resistant to price increases. Psychopharmacology, 167, 180-186.

Shahan, T.A. & Podlesnik, C.A. (2005). Rate of conditioned reinforcement affects observing rate
but not resistance to change. Journal of the Experimental Analysis ofBehavior, 84, 1 17.

Shiffman, S., Ferguson, S.G., Gwaltney, C.J., Balabanis, M.H., Shadel, W.G. (2006). Reduction
of abstinence-induced withdrawal and craving using high-dose nicotine replacement
therapy. Psychopharmacology, 184, 637-644.

Sizemore, O. J., & Lattal, K. A. (1977). Dependency, temporal contiguity, and response
independent reinforcement. Journal of the Experimental Analysis ofBehavior, 27, 119
125.

Skinner, B. F. (1953). Science and human behavior. New York: Macmillian.

Smith, BR, Horan, JT, Gaskin, S, Amit, Z (1999). Exposure to nicotine enhances acquisition of
ethanol drinking by laboratory rats in a limited access paradigm. Psychopharmacology
142, 408-412.

Stewart, G.G. (1967). A history of the medicinal use of tobacco 1492-1860. Medical History, 11,
228-268.

Stewart, J. (1960). Reinforcing effects of light as a function of intensity and reinforcement
schedule. Journal of Comparative and Physiological Psychology, 53, 1 87- 193 .











Stitzer, M., Morrison, J., Domino, E.F. (1970). Effects of nicotine on fixed-interval behavior and
their modification by cholinergic antagonists. Journal ofPharmacology and Experimental
Therapeutics, 171, 166-177.

Stolerman, I.P. (1999). Inter-species consistency in the behavioral pharmacology of nicotine
dependence. Behavioural Pharmacology, 10, 559-580.

Stolerman I, Jarvis M.(1995). The scientific case that nicotine is addictive. Psychopharmacology
(Berlin), 117, 2-10.

Straub, D.M., Hills, N.K., Thompson, P.J., Moscicki, A. (2003). Effects of pro- and anti-tobacco
advertising on nonsmoking adolescents' intentions to smoke. Journal ofAdolescent Health,
32, 36-43.

Tanda, G. & Goldberg, S.R. (2000). Alteration of the behavioral effects of nicotine by chronic
caffeine exposure. Pharmacology, Biochemistry, and Beehavior, 66, 47-64.

Tapp, J.T., Mathwson, D.M., & Simpson, L.L. (1968). Effects of hunger and thirst on
reinforcing properties of light onset and light offset. Journal of Comparative and'
Physiological Psychology, 66, 784-787.

Teneggi,V., Tiffany, S.T., Squassante, L., Milleri,S., Ziviani, L., Bye, A. (2002). Smokers
deprived of cigarettes for 72 h: effects of nicotine patches on craving and withdrawal.
Psychopharmacology, 164, 177-187.

Thompson, T. (2007). Relations among functional systems in behavior analysis. Journal of the
Experimental Analysis ofBehavior, 8 7, 423-440.

Thompson, T. & Schuster, C.R. (1964). Morphine self-administration, food-reinforced and
avoidance behaviors in Rhesus monkeys. Psychopharmacologia, 5, 87-94

Thompson, T. & Schuster, C.R. (1968). Behavioral pharmacology. Englewood Cliffs, NJ:
Prentice-Hall, Inc.

Vale, A.L. & Balfour, D.J.K. (1989). Aversive environmental stimuli as a factor in the
psychostimulant response to nicotine. Pharmacology, Biochemistry and Beehavior, 32,
857-860.

Valentine, J.D., Hokanson, Matta, S.G., Sharp., B.M. (1997). Self-administration in rats allowed
unlimited access to nicotine. Psychopharmacology, 133, 300-304.

Ward, S.J., Lack, C. Morgan, D., Roberts, D.C.S. (2006). Discrete-trials heroin self
administration produces sensitization to the reinforcing effects of cocaine in rats.
Psychopharmacology, 185, 150-159.










Wenger, G.R. & Dews, P.B. (1976). The effects of phencyclidine, ketamine, d-amphetamine and
pentobarbital on schedule-controlled behavior in the mouse. Journal ofPharnzacology
and Experimental Therapeutics, 196, 616-624.

Westman, E. C., Behm, F. M., & Rose, J. E. (1996). Dissociating the nicotine and airway sensory
effects of smoking. Pharmacology, Biochentistly, and Behavior, 53, 309-315.

Williams, B.A. (1994). Conditioned reinforcement: Experimental and theoretical issues. The
Behavior Analyst, 17, 261-285.

Woods, J.H. & Winger, G.D. (2002). Observing responses maintained by stimuli associated with
cocaine or remifentanil reinforcement in rhesus monkeys. Psychopharnzacology, 163,
345-351.

Woolverton WL, Wang Z, Vasterling T, Carroll FI, Tallarida R. (2008). Self-administration of
drug mixtures by monkeys: combining drugs with comparable mechanisms of action.
Psychopharnzacology, 196, 575-582.

Wonnacott, S., Sidhpura, N., Balfour, D.J.K. (2005). Nicotine: From molecular mechanisms to
behavior. Current Opinion in Pharmacology, 5, 53-59.

Wyckoff, L. B. (1952). The role of observing-responses in discrimination learning.
Psychological Review, 59, 43 1-442.









BIOGRAPHICAL SKETCH


My first experiences with behavior analysis and radical behaviorism were with Dr.

Gregory Madden at the University of Wisconsin-Eau Claire. While I was in Eau Claire I took

several behavior analysis courses (e.g., Learning, Applied Behavior Analysis, Advanced

Experimental Analysis of Behavior) and I had the chance to work as a teaching assistant for an

introductory course in behavior analysis. Dr. Madden and I collaborated on two areas of

research: (1) studying potential differences in human responding on a delay discounting task

when the consequences were real versus hypothetical, and (2) investigating whether human

behavior was better described by the matching law when responses were maintained by

concurrent schedules of negative reinforcement versus concurrent schedules of positive

reinforcement. The former proj ect resulted in two publications and the latter project served as my

undergraduate thesis. Both proj ects were presented at the annual conferences for the Association

for Behavior Analysis and the Midwestern Association for Behavior Analysis, providing me with

opportunities to talk to and get feedback from important figures in the field.

As an undergraduate I was introduced to the subdiscipline of behavioral pharmacology,

which was particularly important to me because I was always interested in drug use and abuse.

Specifically, Dr. Madden talked about a behavioral treatment for drug abuse known as

"contingency management." When I began looking for graduate programs I found that Dr. Jesse

Dallery, in the Behavior Analysis program at University of Florida, was conducting research on

contingency management with smokers, in addition to studying issues that were consistent with

the topics I studied as an undergraduate (e.g., matching law, delay discounting). Not only were

Dr. Dallery's research interests a perfect match with mine, but the Behavior Analysis program at

University of Florida also consisted of several other faculty members with broad interests.









While a student at the University of Florida, I have had extensive professional, research,

and academic development experiences. I first authored three manuscripts and co-authored a

number of others. I wrote two grants submitted to the National Institue of Health (an RO3 and

NRSA). I was co-investigator on the RO3 grant which supported the animal research discussed in

this manuscript. In addition to writing, I served as a Graduate Instructor for two semesters, where

I was able to design a course in Applied Behavior Analysis. I conducted numerous research

experiments with Dr. Dallery, ranging from the basic non-human animal studies described in my

dissertation, as well as human laboratory and outpatient research with smokers. In addition to

the research I conducted with Dr. Dallery, I also had the opportunity to collaborate on a couple

of research proj ects with Dr. Timothy Hackenberg, studying token loss as a form of response

cost punishment with pigeons.

Collectively, my undergraduate and graduate school experiences solidified my

enthusiasm about pursuing a career that allows me to teach the principles and theoretical

foundations of behavior analysis and behavioral pharmacology. I am interested in working in an

academic setting that includes a balance between teaching and research.





PAGE 1

1 EFFECTS OF NICOTINE ON RESPONDING MAINTAINED BY ENVIRONMENTAL STIMULI IN RATS By BETHANY R. RAIFF A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2008

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2 2008 Bethany R. Raiff

PAGE 3

3 To Jack, for providing me with alternative sources of reinforcement

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4 ACKNOWLEDGMENTS I thank my mother Rosanne Gilman, for making me go to college an d for being a constant source of support and I thank my father Arnold Raiff, for his continuous enthusiasm regarding my work I thank my sister, Jennifer Philips, for being a gre at role model, and I thank my brother, Elijah Raiff, for allowing me to be hi s role model. I thank Matthew Locey for paving the way I thank Anthony Defulio, Julie Marusich, and Katie Saulsgive r for being a supportive cohort ; and I thank Steven Meredith and Jeb Jones for helping conduct experimental sessions. I thank Dr. Gregory Ma dden for introducing me to b ehavior a nalysis and for allowing me to come into contact with a rich schedule of reinforcement early in my career. I thank Dr. Timothy Hackenberg for asking me intriguing philosophical questions giving me the opportunity to le arn new and interesting research techniques i n his lab, and for always having an open office door. I thank Dr. Marc Branch for last minute consultations on issues related to behavioral pharmacology, and I thank Drs. Neil Rowland and Adriaan Bruijnzeel for providing useful insights regarding my research. Finally, I thank my advisor, Dr. Jesse Dallery, for constantly challenging me, always b eing available for engaging and productive conv ersatio ns, and for making many exciting opportunities available to me

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ ............... 4 LIST OF TABLES ................................ ................................ ................................ ........................... 7 LIST OF FIGURES ................................ ................................ ................................ ......................... 8 ABSTRACT ................................ ................................ ................................ ................................ ..... 9 CHAPTER 1 GENERAL INTRODUCTION ................................ ................................ ............................... 11 Brief History of Tobacco and C igarette Smoking in the United States ................................ .. 11 The Culprit: Nicotine? ................................ ................................ ................................ ............ 12 Drug Self Administration ................................ ................................ ................................ ....... 13 Nicotine Self Administration ................................ ................................ .......................... 15 Motivating Operation Role for Nicotine ................................ ................................ ......... 18 Alternative Accounts ................................ ................................ ................................ ....... 20 Present Experiments ................................ ................................ ................................ ............... 22 2 EXPERIMENT 1 ................................ ................................ ................................ .................... 24 Introduction ................................ ................................ ................................ ............................. 24 Conditioning a New Response ................................ ................................ ........................ 24 Observing response ................................ ................................ ................................ ......... 26 Resistance to Extinction ................................ ................................ ................................ ......... 28 Purpose of Experiment 1 ................................ ................................ ................................ ........ 29 Method ................................ ................................ ................................ ................................ .... 29 Subjects ................................ ................................ ................................ ............................ 29 Apparatus and Materials ................................ ................................ ................................ .. 30 Procedure ................................ ................................ ................................ ......................... 30 Results ................................ ................................ ................................ ................................ ..... 36 Discussion ................................ ................................ ................................ ............................... 40 3 Experiment 2 ................................ ................................ ................................ ........................... 57 Introduction ................................ ................................ ................................ ............................. 57 Purpose of Experiment 2 ................................ ................................ ................................ ........ 58 Methods ................................ ................................ ................................ ................................ .. 59 Subjects ................................ ................................ ................................ ............................ 59 Apparatus and Materials ................................ ................................ ................................ .. 59 Procedure ................................ ................................ ................................ ......................... 59 Results ................................ ................................ ................................ ................................ ..... 63 Discussion ................................ ................................ ................................ ............................... 67

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6 4 General Discussion ................................ ................................ ................................ ................. 80 Mechanisms of Action ................................ ................................ ................................ ............ 80 Behavioral Mechanisms ................................ ................................ ................................ .. 80 Neurobiological Mechanisms ................................ ................................ .......................... 85 Concluding Remarks ................................ ................................ ................................ .............. 87 LIST OF REFERENCES ................................ ................................ ................................ ............... 88 BIOGRAPHICAL SKETCH ................................ ................................ ................................ ....... 101

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7 LIST OF TABLES Table page Table 2 1. Hypothetical effects of nicotine on responding maintained by each of the response types investigated with the observing response procedure ................................ 45 Table 2 2. Mean + SEM DI Observing response rate, food extinction response rates in the presence of the S+ and S from the five sessions prior to the Drug Administration condition ................................ ................................ ................................ ............................ 46 Table 2 3. Mean + SEM response r ates just prior to and during the Drug Administration condition for food extinction response rates in the presence of the S+ and S and for observing responses ................................ ................................ ................................ ........... 47 Table 2 4. Fitted parameter values and corresponding r 2 for each linear regression applied to the rate dependent graphs shown in Figure 2 8. ................................ ................................ 48 Table 3 1. Proportion of responses on the active lever ................................ ................................ .. 71 Table 3 2. Proportion of stimulus presentations during which a response was made ................... 72 Table 3 3. Fitted parameter values and corresponding r 2 for ea ch linear regression applied to the rate dependent graphs shown in Figure 3 6. ................................ ................................ 73

PAGE 8

8 LIST OF FIGURES Figure page Figure 2 1. Experiment 1 S chematic. ................................ ................................ ............................ 49 Figure 2 2. Pretests. ................................ ................................ ................................ ...................... 50 Figure 2 3. Mean ( + SEM) Food Extinction S+, S and Observing Responses. ............................ 51 Figure 2 4. Individual S ubject Data S howing Food Extinction R esponses on the S+. ................. 52 Figure 2 5. Individual Subject Data S howing Food Extinction R esponses on the S .................. 53 Figure 2 6. Individual Subject Data Showing Observing R esponses. ................................ ........... 54 Figure 2 7. Resistance to Extinction.. ................................ ................................ ............................ 55 Figure 2 8. Rate D ependent S catterplots. ................................ ................................ ...................... 56 Figure 3 1.Total Responses D uring Lights On. ................................ ................................ ........... 74 Figure 3 2. Total Responses D uring Lights Off.. ................................ ................................ .......... 75 Figure 3 3. Cumulative Response Records D uring Lights On.. ................................ .................... 76 Figure 3 4. Cumulative Response Records D uring Lights Off.. ................................ .................... 77 Figure 3 5. Within SessionTime Course Analyses.. ................................ ................................ ...... 78 F igure 3 6. Rate D ependent Scatterplots. ................................ ................................ ..................... 79

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9 Abstract of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy EFFECTS OF NICOTINE ON RESPONDING MAINTAINED BY ENVIRONMENTAL STIMULI IN RATS By Bethany R. Raiff May 2008 Chair: Jesse Dallery Major: Psychology Past research suggests that nicotine induced increases in reinforced responding are due to its r einforcer enhancing effects It is unclear whether this role is specific to certain kinds of reinforcing consequence s (e.g., sensory stimuli, edible re inforcers, drug reinforcers ). Furthermore, it is possible that nicotine merely increases behavior that ha s been trained in the past (i.e., responding reinforced with food consequences) The objective s of Experiment s 1 and 2 were to test the generality of the motivating establishing operation (MEO) accoun t of nicotine induced increases in reinforced responding and to determine whether the history of training (responses that have previously been reinforced with food versus those that have not ) would augment the effects. Experiment 1 used an observing response procedure to investigate responding maintained by fo od reinforcers, conditioned reinforcers (i.e., visual stimuli) and responding during extinction. Rats in Experiment 1 received pre session subcutaneous injections of vehicle (n = 5), 0.3 (n = 6) or 0.56 (n = 6) mg/kg nicotine for 70 sessions. Resistance t o extinction was also assessed by removing food for five sessions. Nicotine did not consistently affect food or extinction responding. Both doses of nicotine produced increases in responding maintained by

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10 conditioned reinforcers, but did not increase resis tance to extinction. Pre drug response rates accounted for a small but significant percentage of the variance in the drug effect. In Experiment 1, contingent houselight presentations alone were shown to slightly increase response rates from operant levels Experiment 2 further evaluated the putative primary reinforcing functions of turning on and turning off a houselight. One group of rats (n=4) was initially trained to press both levers (one was later designated as the active lever and the other the inact ive lever) while a different group of rats (n =4) was only trained to press the lever that was later designated as the active lever. Across two phases, five responses on the active lever resulted in the houselight either turning on (Lights On) or turning off (Lights Off). All subjects made more responses on the active lever, regardless of lever training history and the type of stimulus change, suggesting that both stimuli served as primary reinforcers. N icotine only increased responding on the active lever again regardless of lever training history, which further support ed the MEO role, and refute d the alternative hypothesis that nicotine generally increases behavior that has been trained. Although there was a tendency for nicotine to increase low pre dru g response rates in both experiments nicotine systematically increased responding maintained by conditioned reinforcers in Experiment 1, and only increased responding on an active lever in Experiment 2 The results of both experiments are in accord with t he MEO account of nicotine that it increase s responding maintained by moderately reinforcing stimuli, such as the conditioned reinforcers and visual stimuli used in the present stud ies

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11 CHAPTER 1 GENERAL INTRODUCTION Brief History of Tobacco and Ci garette Smoking in the United States Tobacco use by humans dates back centuries ranging from religious recreational and at times even medicinal uses Columbus and his crew first introduced to bacco to Spain after visiting the Americas in 1492 and seeing a number of indigenous N orth At the time, many N orth Americans considered tobacco sacred and in some cases medicinal (Hatch, 1942; Kluger, 1997). Although tobacco was initially used by Europeans for recreational purposes, from the 1600s until the mid 1800s it was considered the Eu rope and the United States, being prescribed to treat various ailments such as asthma, nasal congestion, thirst, wounds, teeth whitening, and even the bubon ic plague (Stewart, 1967). Eventually p hysicians became skeptical of the substance because of ties, and by around 1860 tobacco was no longer being prescribed for medicinal purposes (Stewart, 1967). Nevertheless it wa s not long after, around 1880, when the first cigarette rolling machines were invented, which led to the mass production and sales of cigarettes for predominantly recreational purposes (Gold, 1995). With increasing sales came increasing economic interest in tobacco in the United States. The New Tobacco Company was formed in 1889 and 10 years later RJ Reynolds, the makers of well known Camel cigarettes, was incorporated In 1902 Philip Morris and Company, makers of Marlboro cigarettes, came to New York (Klu ger, 1997), and today Philip Morris claim s more than 50% of the U.S. tobacco market (Cooper, 2004). In the U.S alone, over 100,000 hectares of land are devoted to growing tobacco, with most of the farms located in North Carolina (Food and Agricultural Org anization, 2003; Gold, 2005).

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12 between smoking and cancer and the Federal Cigarette Labeling and Advertising Act of 1965 required that all tobacco products bear a warn ing label (Centers for Disease Control and Prevention [CDC], 2006). Since 1965, the percentage of current smokers has declined from about 42%, remaining at an estimated 24% of the U.S. adult population since 2003 (CDC, 2006). In addition to cancer, smoki ng has been associated with a number of other health problems, such as emphysema, coronary heart disease, and stroke, with approximately 440,000 deaths attributed to smoking related illnesses each year (CDC, 2005). Although about 70% of smokers report a d esire to quit (CDC, 2005), approximately 60 90% of those who attempt to quit end up relapsing within one year (Carmody, 1992). Cigarette smoking is currently a primary public health concern in the United States. Despite this long history of tobacco use in the United States, the question remains: w hat has made tobacco such a successful commodity? The Culprit: Nicotine? The answer s of course are complex. Each year tobacco companies spend over $15 billion dollars on advertising almost $50 million per d ay (Federal Trade Commission, 2005) reported intentions to smoke cigarettes (Straub, Hills, Thompson, Moscicki, 2003) and smoking initiation (Pierce, Choi, Gilpin, Farkas, Berry, 1998 ). In addition to social and cultural influences on smoking, the pharmacological effects of nicotine have been implicated in the success of tobacco products Of the approximately 4,000 constituents found in tobacco, the primary psychoactive ingredient is nicotine, which was first extracted from tobacco in 1828 (Henningfield & Zeller, 2006). The effects of nicotine on the central nervous system are similar to the effects of other drugs of abuse, such as cocaine, heroin, and amphetamine, in that they all aff ect the mesolimbic dopamine system (McKim, 1997; Pierce

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13 & Kumaresan, 2006; Wonnacott, Sidhpura, Balfour, 2005) Each drug affects the area in a slightly di fferent way, but they all result in dopamine release either directly or indirectly. Research suggest s that it is particularly important that the drug result in increased dopamine activity in the ventral tegmental area and the nucleus accumbens, which nicotine does both directly by stimulating dopamine neurons and indirectly by initiating glutamate releas e (Pierce & Kumaresan, 2006). Because these effects on the mesolimbic dompamine system appear to be critical to the reinforcing effects of most other drugs of abuse, the fact that nicotine also has these effects suggests that its presence in tobacco produc ts might be responsible for the high rates of tobacco use ( Stolerman & Jarvis, 1995; Stolerman, 1999). Behavioral pharmacologists have been particularly interested in determining whether nicotine is responsible for smoking maintenance and relapse, and have used the self administration procedure to explore this possibility. Drug Self Administration The discipline of behavioral pharmacology combines the principles of pharmacology with the principles of behavior analysis (Poling & Byrne, 2000; Thompson & Schus ter, 1968). Behavior analysis uses a natural science approach to understanding the behavior of organisms, and places an emphasis on environmental variables (Cooper, Heron, Heward, 2007 ; Skinner, 1953 ). Operant behavior, in contrast with respondent behavior is defined as behavior whose future likelihood is affected by its consequences, and it comprises most of the behavior of humans ( Cooper, Heron, Heward, 2007 ; Skinner, 1953 ). Although there are many facets of both operant and respondent conditioning that are of interest to behavioral pharmacologists, one area that has generated interest is reinfo rcement Reinforcement is the process by which a response occurs, a stimulus event follows, and th e result is an increase or maintenance in the future probability of the response (Poling & Byrne, 2000; Skinner, 1953 ; Thompson & Schuster, 1968). Behavioral pharmacologists have extended the concept of reinforcement by conceptualizing

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14 drugs as potential reinforcers and drug seeking and use as operant behavior (Carlton, 1983; McKim, 1997; Poling & Byrne, 2000). For human smokers, these behaviors might include going to the store to buy cigarettes, asking another smoker for a cigarette, inhaling the smoke, etc., with nicotine as the key ingredient thought to be in volved i n the reinforcing function of the cigarettes. Drug self administration procedures were developed by behavioral pharmacologists for use with nonhuman subjects under controlled laboratory conditions (Carlton, 1983; Haney & Spealman, 2008 ), and are considered analogous to human drug use and drug seeking. Self administration procedures are often conducted in operant chambers whereby the drug is delivered (usually intravenously through a catheter) after a response is made (e.g., a lever press with rats or non hu man primates; Thompson & Schuster, 1964). For example, the lever press that results in a nicotine infusion would be considered functionally equivalent to a smoker lifting administration studies demonstrated that nonhumans would self administer drugs such as morphine and cocaine on various schedules of reinforcement (Thompson & Schuster, 1964; Pickens & Thompson, 1968) Thompson and Schuster (1968) demonstrated that the patterns of responding main tained by morphine were similar to the patterns of responding maintained by food, and that morphine deprivation had similar effects as food depriva tion on those response patterns. These findings provided empirical support for the notion that drugs could pr oduce effects that were similar to other reinforcing consequences. One method that has also been used to further investigate the reinforcing function of a drug involves delivering an agonist or antagonist of the drug, either before the session or nonconti ngent o n responding during the session, and determining self administration of the drug itself is influenced For example, i n one study baboons were given a choice between earning

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15 foo d and self administering heroin. Subjects chose to self administer heroin on approximately half of th e trials When noncontingent morphine an opioid agonist, was added to the session the number of heroin choices decreased. In this case, m orphine could be considered a substitute for heroin, which led subject s to allocate their choices to food instead of heroin Similar changes in choice allocation were seen when nal o xone (an opioid antagonist) was given suggesting that it blocked the reinforcing effects of heroin (Grif fiths, Wurster, Brady, 1981). Nicotine Self Administration It has long been argued that the widespread use of tobacco products can be attributed in part, to properties ( Russell, 1971; Stolerman & Jarvis, 1995). However, unlike most other drugs of abuse, it has been very difficult to establish nicotine self administration in nonhumans Eventually, in 1989 Corrigal and Coen (1989) published a study that seemed to convincingly demonstrate nicotine self adm inistration in laboratory rats The procedure involved several features that now seem to be important for generating nicotine self administration The rat was food deprived and then trained to press one of two levers F ood was used as the consequence When lever pressing was established, food wa s replaced with nicotine for pressing th e previously trained lever and the other lever wa s designated inactive. Event ually an intermittent (fixed ratio [FR]) schedule was introduced, where by a fixed number of responses we re required for each in fusion. Each nicotine infusion wa s paired with the brief onset of a stimulus light above the active lever followed by a 60 s time out, during which all visual stimuli, including the houselight, we re turned off. Sessions were 1 hr in duration and the entire experiment lasted for a few weeks to one month, b ut rarely longer Since the publication of this procedure in 1989, it has been the predominant method used to study nicotine self administration (e.g., Cohen, Perrualt, Griebel, Soubri, 2005; Corrigal & Coen, 1989; Caggiula et al., 2001, 2002a,b; Chaudhri et al., 2006a ; Donny et al., 2003 ). Variations of this procedure sometimes

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16 involve more extended access to nicotine (e.g., 23 hr / day), the use of nonhuman primate subjects, and in some cases omitting the food deprivation and lever training protocols (D enoble & Mele, 2006; Goldberg, Spealman, Goldberg, 1981; Harris, Burroughs, Pentel, Lasage, 2008; Valentine, Hokanson, Matta, Sharp, 1997). It should be noted, however, that in all of the procedures just cited, some form of stimulus change always accompani ed the nicotine infusion s In fact, the stimulus change accompanying each nicotine infusion appears to play a critical role in nicotine self administration with nonhumans. Caggiula and colleagues have conducted a number of experiments demonstrating that wh en the stimulus change is removed, nicotine self administration decreases to levels that are almost indistinguishable from vehicle self administration (Caggiula, et al., 2001; Caggiula, Donny, Chaudhri, Perkins, Evans Martin, Sved, 2002a; Caggiula et al., 2002b; Chaudhri et al., 2005). Caggiula and colleagues (2002b) conducted a systematic investigation into the features of the stimulus change (e.g., turning on a houselight, turning on a light above the lever, turning off a houselight, or turning on a brief lever light and tone). The authors found that turning off a houselight maintained more responding than the other stimuli and that adding contingent nicotine increased responding maintained by turning off the houselight to a greater extent than the other stimulus changes investigated Furthermore, when nicotine was removed, but turning off the houselight continued to be presented contingent on a FR 5 schedule of lever pressing, responding decreased substantially ( Caggiula et al., 2001) This finding led th e researchers to conclude that nicotine did in fact function as a primary reinfor cer, albeit a weak one Although it is possible that nicotine serves as a weak primary reinforcer, it is also possible that the mere presence of nicotine has behavioral effec ts that make it appear to function as a reinforcer (Branch, 200 6 ) One technique that ha s been employed to distinguish between the

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17 reinforcing effects of a stimulus, as opposed to its eliciting or discriminative effects, is to deliver the stimulus response indep endent ly ( Pickens & Thompson, 19 68 ; Sizemore & Lattal, 1977 ). Donny and colleagues ( Donny et al., 2003 ) did just that by exposing one group of rats to the traditional self administration paradigm described above and yoking the nicotine infusions ear ned by this group to a different group of rats who only earned stimulus changes contingent on lever pressing. Interestingly, the group of rats who received yoked nicotine infusions responded almost as much on the stimulus change lever as the group who earn ed contingent nicotine plus contingent stimulus changes. To rule out adventitious reinforcement in the yoked group, a second study was conducted that involved one continuous infusion of nicotine during each session along with response contingent stimulus changes. As in the yoked experiment, the mere presence of nicotine resulted in increases in responses maintained by the visual stimulus change A number of other studies have been conducted to further corroborate the finding that nicotine increases respond ing maintained by stimulus changes (Chaudhri et al., 2006; Olausson, Jentsch, & Taylor, 2004a, b ; Palmatier et al., 2006, 2007; Raiff & Dallery, 2006). In addition to increasing responses maintained by moderately reinforcing sensory stimuli, nicotine has a lso been shown to increase responding maintained by more potent primary reinforcers, such as cocaine (Bechtholt & Mark, 2002; McQuown, Belluzi, Leslie, 2007), alcohol (Clark, Lindgren, Brooks, Watson, Little, 2001; L, Wang, Harding, Juzytsch, Shaham 2003 ; Smith, Horan, Gaskin, Amit, 1999) and sucrose dissolved in water (Jias & Ellison, 1990). many researchers maintain the position that nicotine serves as a primary reinforcer (e.g., Chaudhri et al., 2006; Le Foll, Wertheim, Goldberg, 2007) Thus, there are at least two roles for nicotine: (1) nicotine functions as a primary reinforcer that can maintain responding in the absence of visual stimuli

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18 and can establish neutral stimuli as co nditioned reinforcers and (2) nicotine can enhance the reinforcing efficacy of other reinforcers when delivered contingent or noncontingent on a response (Chaudhri et al., 2006). The viability of the first role is beyond the scope of this paper -instead the hypothesis that nicotine acts as a reinforce r enhancer will be explored in the section that follows. Motivating Operation Role for Nicotine In behavior analysis, the concept of motivating operations is critically important to the concept of reinforcem ent in general A motivating operation (MO) is an antecedent event that ( 1 ) temporarily alters the efficacy of certain consequences (reinforcer value altering), and ( 2 ) changes the likelihood of responses that have resulted in that consequence in the past (response altering; Laraway, Snycerski, Michael; Michael, 1982; Michael, 1993; Michael, 2000). MOs can either work by increasing or decreasing the efficacy of certain consequences, and thus increasing or decreasing the future probability of a response, res pectively. The former is often referred to as an establishing operation the latter an abolishing operation (Michael, 1982). For example, food deprivation is an establishing operation because it temporarily increases the reinforcing value of food, and thus increases the likelihood of responses that have previously resulted in receipt of food. Alternatively, food satiation is an abolishing operation and thus decreases the likelihood of responses which have led to the receipt of food in the past. For the pur poses of this discussion, only those antecedent events that increase the future likelihood of a response will be discussed and they will be summarized by the term mo tivating establishing operation (MEO). The concept of the MEO has been fruitful and practi cal in applied behavior analysis (Dicesare, McAdam, Toner, Varrell, 2005; Iwata, Dorsey, Slifer, Bauman, Richman, 1994; Iwata, Smith, Michael, 2000; McAdam et al, 2005; McComas, Hoch, Paone, El Roy, 2000;

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19 Northup, Fusilier, Swanson, Roane, Borrero, 1997). A lthough the principles of reinforcement, punishment, and stimulus control have been widely applied to behavioral pharmacology research (Branch, 2006; Carlton, 1983; Thompson & Schuster, 1968) the concept of the MEO has been neglected. Only two known stud ies directly applied the concept of MOs to drug effects (Dicesare, McAdam, Toner, Varrell, 2005; Northup, Fusilier, Swanson, Roane, Borrero, 1997). One study found that the disruptive behavior of an individual with attention deficit hyperactivity disorder (ADHD) was reinforced by therapist attention, but only in the absence, and not the presence, of methylphenidate treatment (Dicesare, McAdam, Toner, Varrell, 2005). This is an example of how the drug served as an abolishing operation (i.e., it decreased the reinforcing efficacy of attention). Another study found that methylphenidate increased the relative reinforcing efficacy of some classroom activities for a child with ADHD, while it decreased the relative reinforcing efficacy of edible items for the same child, suggesting that the drug could function as an establishing operation in some cases and an abolishing operation in others. Both of the studies just described were conducted by applied behavior analysts and published in the Journal of Applied Behavi or Analysis Thus the application of MOs to the more general behavioral pharmacology community was not made. enhancing effects are consistent with a MEO account. If nicotine does in fact serve as a MEO, it should increase the value of some reinforcers, and increase the likelihood of responses which have led to the receipt of those reinforcers in the past. Co nceptualizing nicotine as a MEO provide s a unifying behavioral mechanism of action Furthermore, investigating the MO rol e of drugs could be fruitful, both conceptually and empirical ly, in behavioral pharmacology in general (Poling & Byrne, 2000; Thompson, 2007).

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20 Alternative Accounts In pursuing the putative MEO role of nicotine, alternative explanations regarding how nico tine m ight affect behavior must also be considered T he following section s discuss the potential rate dependent effects of nicotine and the possibility that nicoti ne merely increases behavior. Rate Dependence. One of the most well known and influential phenomen on in behavioral pharmacology is rate dependence. In 1955, Dews conducted an experiment showing that pentobarbita l could have opposite effects on behavior depending on the schedule of reinforcement maintaining the response (ratio or interval) th e same dose decreased responding on an interval schedule and increased responding o n a ratio schedule. This finding was perplexing at the time because it contradicted the notion that some drugs are stimulants and always increase behavior while other drugs are depressants and always decrease behavior Consequently, behavioral pharmacologists began placing greater emphasis on e nvironmental variables due to their clear interaction with drug effects ( Branch, 1984 ) Since nstrated repeatedly that base line pre drug, rates of responding are related to the he most common ra te dependent effects involve increases in low pre drug response rates and decreases in high pre drug response rates. Rate dependent effects have been demonstrated both within subject and across subjects, and for a number of different drugs, but most often with amphetamine ( Lucki, 1983; Saulsgiver, McClure, Wynne, 2007; Wenger & Dews, 1976 ). Rate dependent effects are typically plotted as a log percentage of pre drug response rates (i.e., drug/pre drug x 100) as a function of log pre drug response rates. Linear regression analyses are then performed on the data, revealing a negative slope if rate dependent effects exist such that

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21 low pre drug rates increase and high pre drug rates decrease (Branch, 1984; Poling & Byrd, 2000) and a slope of zero if rate dependent effects do not exist Almost all of the studies that have bee n u sed to support the reinforcer enhancin g account of nicotine have involved low response rates that increase when nicotine is present ( Chaudhri et al., 2006; Olausson, Jentsch, & Taylor, 2004a, b ; Palmatier et al., 2006, 2007; Raiff & Dallery, 2006). There are no known studies with laboratory an imals that have directly applied rate dependent analyses described above to the effects of nicotine. H owever, Perkins (1999) conducted a review of research on nicotine and found a few instances t hat were consistent with rate dependent effects (Shaefer & Mi chael, 1986; Stitzer, Morrison, Domino, 1970; Vale & Balfour, 1989). For instance, in one study intermediate doses of nicotine did not affect the high rates of responding maintained by a FR1 schedule of intracranial brain stimulation (ICSS), but the same d oses did increase the lower rates of responding maintained on a FR 15 schedule of ICSS (Shaefer & Michael, 1986). Due to the relative dearth of research aimed at eva luating rate dependent effects with nicotine, and the pervasiveness of the phenomenon with other drugs, the need for a more systematic investigation is warranted. It is possible that the increases in responding that occur as a function of nicotine administration can be entirely accounted for (although not necessarily explained) by pre drug rates of responding. General Motoric Effects. Probably the most outspoken about their disagreement with the conclusion that nicotine serves as a prima ry reinforcer or a reinforcer enhancer are Hanan Frenk and Reuven Dar (Frenk & Dar, 2000, 2004; Dar & Frenk, 2 002a, b, 2004, 2005). Frenk and Dar have suggested that the nicotine induced increases seen in laboratory animals can be accounted for by the general locomotor increasing effects of nicotine. Many of the studies used as evidence of nico tin r reinforcer enhancing roles have argued against the

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22 general locomotor activity account by explaining that increases in responding only occur on the active lever, with the inactive lever used as a control for general, undifferentiated increases in respondi ng (e. g., Chaudhri et al., 2006 ). Recall that in these experiments subjects were initially trained with food to press the active lever only. Frenk and Dar (2004) argued that comparing active to inactive lever presses was not justified because inactive resp onses were never reinforced In other words, Frenk and Dar believe that only responses that have been trained should be expected to increase when nicotine is delivered. Furthermore, there are a number of studies that have demonstrated nicotine l ocomotor increasing effects when st udied in an open field activity chamber ( Dwoskin, Crooks, Teng, Green, Bardo, 1999; Faraday, Elliott, Phillips, Grunberg, 2003; Green, Cain, Thompson, Bardo, 2003; Koehl, Bjijou, Le Moal, Cador, 2000; Kosowski & Liljequis t, 2005; Panagis, Nisell, Nomikos, Chergui, Svensson, 1996 ). Thus, while evaluating the potential MEO effects of nicotine it will be necessary to consider the possibility that nicotine increases activity in general. Present Experiments In the sections t hat follow, two experiments are described that sought to investigate the MEO account of nicotine induced increases in responding, while also considering the possible rate dependent and general activity increasing effects of the drug. The first experiment e valuated the generality of the MEO account by studying the effects of nicotine on responding maintained by sucrose based food pellets and conditioned reinforcers, as well as investigating the effects of nicotine on responding during periods of extinction. The second experiment further assessed the potential primary reinfor cing function of the visual stimuli used in Experiment 1 and the visual stimuli used in nicotine self administration studies. Furthermore, two groups of rats were given

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23 different lever tra ining histories to determine whether such differences would influence the effects of nicotine.

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24 CHAPTER 2 EXPERIMENT 1 Introduction The stimuli associated with nicotine infusions have been conceptualized as conditioned reinforcers because of their repeated pairings with nicotine (Caggiula et al., 2001) and have been compared to the stimuli that are associated with nicotine delivered from cigarettes such as the smell and taste of smoke (Chaudhri et al., 2006). It has become increasingly clear that the stimu li associated with cigarettes may contribute to smoking maintenance and relapse (Dallery, Houtsmuller, Pickworth, & Stitzer, 2003; Dar & Frenk, 2004; Dols, Willems, & van den Hout, 2000; Field & Duka, 2001; Rose, Behm, Westman, & Johnson, 2000; Rose, Tashk in, Ertle, Zinser, & Lafter, 1985; Westman, Behm, & Rose, 1996 ). Although a number of procedures have been used to study conditioned reinforcement ( Kelleher & Gollub, 1962; Williams, 1994) the two procedures most relevant to the current research will be d iscussed in detail: the procedures Conditioning a New Response T he conditioning a new response procedure was recently used to study self administered and experimenter delivered effects of nicotine on responding maintained by conditioned reinforcers (Olausson, Jentch, & Taylor, 2004a, b; Chaudhri et al., 2006). This procedure involves pairing a stimulus (e.g., light & tone) with a primary reinforcer (e.g., water or sucrose ). After many exposures of the light and tone paired with the primary reinforcer a new response is trained (e.g., pressing a lever) by having the response produce the light and tone in the absence of the primary reinforcer If the response is acquired, the stimulus is said to be a cond itioned reinforcer because the primary reinforcer wa s never made contingent on this new response. When rats were injected with nicotine prior to sessions using the conditioning a new response procedure, they responded more for the conditioned reinforcer th an when they were given

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25 vehicle (Olausson et al., 200 4a ). When a different group of rats were injected with nicotine for 15 consecutive days prior to the conditioning a new response procedure they responded more to produce conditioned reinforcers than rats given vehicle for 15 consecutive days (Olausson et al., 2004 b ). These results suggest that nicotine potentiates responding acquired by the putative conditioned reinforcer when it is delivered during, or prior to, acquisition of a new response this find ing is consistent with the MEO account of nicotine discussed earlier Although the conditioning a new response procedure is highly regarded for studying conditioned reinforcement, it has several limitations compared to other procedures (Fantino, 1977; Wil liams, 1994). In the experiments described above, it is not clear whether the light and tone were actually conditioned reinforcers. The authors never measured responding for these stimuli prior to pairing them with the primary reinforcer S ome visual stim uli have been shown to serve as weak primary reinforcers, even without being paired with other primary reinforcers ( Goodrick, 1970; Robinson, 1959; Segal, 1959; Stewart, 1960; Tapp, Mathewson, Simpson, 1968 ). Even if the stimuli are conditioned reinforcers another limitation of the procedure is that only a few sessions can be conducted before responding begins to diminish This is because during the acquisition of a new response, pairing between the primary and conditioned reinforcer is broken that is, the conditioned reinforcer is placed on extinction because it is no longer associated with primary reinforcement. One can only observe a few days of responding for conditioned reinforcers before it b ecome s less likely and eventually cease s (Williams, 1994). I f an effect of nicotine on extinction were the only question, this method would be sufficient; however, it restricts the generality of the results because typically nicotine is taken daily over long periods of time in the presence of conditioned reinforcer s. Finally, this procedure only assesses effects of nicotine on putative

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26 conditioned reinforcers, while failing to detect potential effects on other reinforcing consequences (Donny et al., 2003). Observing response The observing response procedure can be u sed to study a number of environment al events conditioned reinforcement being one of them (Wyc k off, 1952 ). This procedure has been used to investigate the conditioned reinforcing properties of drug associated stimuli; specifically, cocaine and remifentani l (Woods & Winger, 2002) and ethanol (Shahan, 2003). The observing response procedure involves presenting one stimulus (e.g., red light; S+) with periods of food availability and a different stimulus (e.g., blue light; S ) with periods of extinction (i.e., no food availability). Typically there is one response that produces food (i.e., food responses), when it is avai lable and a different response, hereafter the observing response, that briefly turns on the stimulus associated with the schedule in effect I t should be noted that observing responses are not required for food deliveries to occur and making observing responses do es not have any e ffect on the probability of food being delivered. Over the years there has been controversy regarding why the stimul i in observing response procedures function as reinforcers. Some have argued that it is because of the conditioned reinforcing properties of the stimuli ( Case & Fantino, 1981 ; Williams, 1994 ), while others have argued that it is because of the information provided by the stimuli ( Berlyne, 1957; Hendry, 1969 ). Proponents of the information hypothesis argued that observing responses occurred because they reduced uncertainty about how to respond in a particular situation The S+ and S both provide an equal am ount of information regarding how to respond, and thus either stimulus should maintain observing responses similarly However, a n extensive amount of research has shown that observing responses are primarily maintained by the stimulus associated with food (S+) and not

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27 extinction (S ; Case & Fantino, 1981; Dinsmoor, 1983; Dinsmoor, Brown, & Lawrence, 1972 ) supporting a conditioned reinforcement account. There are several reasons to prefer the observing response method to other methods of studying condition ed reinforcement. First, it is possible to examine effects of several different kinds of responses during all sessions: ( 1) responses maintained by food, ( 2) responses that have never been explicitly reinforced during extinction, and ( 3) responses maintain ed by conditioned reinforcers. Table 2 1 illustrates four hypothetical outcomes regarding the effects of nicotine on each response type just listed. As Table 2 1 shows, the observing response procedure allows for the identification of selective increases in responses maintained by primary or conditioned reinforcers (Outcomes #1 or #2), as well as general increases in responding (Outcome #3) as proposed by Frenk and Dar (2004). One possible limitation of the observing response procedure is if increases wer e to occur on both the food and observing lever at the same time (Outcome #4). If this were to happen it would consequence, or whether increases in observing responses were the indirect result of increases the value of the back up primary reinforcer, food. In fact, it has been demonstrated that increases and decreases in the magnitude of the back up reinforcer result in increases and decreases in the rate of ob serving respon ses, respectively (Shahan, 2002 ). The value of the conditioned reinforcer is necessarily associated with the value of the primary reinforcer. If increases in observing responses were indirectly related to increases in the value of the primary reinforcer in this example, one would expect food maintained responses to increase prior to, or at the same time as, observing responses. Thus, given that all responses are recorded simultaneously, the observing response

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28 procedure provides a method for is olating the effects of nicotine on different environmental consequences. In a recent experiment conducted in our lab, Raiff and Dallery (2006) used an observing response procedure to investigate the effects of nicotine, and found that intermediate doses of subcutaneous (s.c.) injections of nicotine (i.e., 0.1, 0.3 and 0.56 mg/kg base) increased observing responses during acute and chronic nicotine administration. Furthermore, slight increases in food maintained responding were found, but only after chroni c nicotine administration. This addresses the concern just described in the previous section, suggesting that the increases in observing responses were independent of potential changes in the value of food The findings from this study were consistent wit h the hypothesis that nicotine served as a MEO for the conditioned reinforcers, and it suggests that under some conditions it may even serve as a motivating operation for a more potent primary reinforcer namely, food However, Raiff and Dallery (2006) re lied solely on rate of responding to infer changes in the value of the reinforcer (i.e., rate of observing responses increased under some doses of nicotine) Another method that has been used to infer the relative value of a reinforcer is resistance to ext inction (Nevin, 1974). Resistance to Extinction The MEO account specifies that responding will increase when the reinforcing stimuli are available or made contingent on some response. Moreover, if nicotine serves as a MEO by increasing the value of reinfor cer s then subjects exposed to nicotine should be more resistant to extinction when reinforcing stimuli are withdrawn. Such a prediction follows from behavioral momentum theory, which distinguishes between response reinforcer relations and stimulus reinfor cer relations (Nevin, 1974). Response reinforcer relations suggest that the contingencies of reinforcement are responsible for engendering different response rates. For instance, a variable

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29 ratio schedule will produce a higher rate of responding than a fix ed ratio schedule of equal value. Stimulus reinforcer relations, on the other hand, suggest that situations with a higher rate or larger amount of reinforcement will have greater value, which results in greater resistance to extinction (Nevin & Grace, 2000 ). A number of studies have corroborated this distinction by showing that r esponses maintained by a richer schedule or greater amount of reinforcement will be more resistant to extinction than responses maintained by a leaner rate or lower amount of reinfo rcement regardless of the rate of responding before extinction (Nevin & Grace, 2000; Nevin, 1974). Thus, if nicotine increases the value of primary and conditioned reinforcers, then responding should be more resistant to extinction when nicotine is presen t compared to when nicotine is absent. Purpose of Experiment 1 Experiment 1 sought to: ( 1 ) replicate the findings reported by Raiff and Dallery (2006) by administering different doses of nicotine (0.3 and 0.56 mg/kg the doses that consistently produced increases in responding) across groups of rats, ( 2 ) investigate whether nicotine induced changes in responding could be des cribed as rate dependent, and ( 3 ) assess whether the behavior of rats exposed to nicotine are more resistant to extinction than the b ehavior of rats exposed to vehicle. Method Subjects Subjects were eighteen naive male Long Evans rats (Harlan; Indianapolis, IN). The rats were approximately 150 days old at the beginning of the experiment. They were individually housed in hanging polyc arbonate cages with bedding, in a room that was temperature and humidity controlled. Subjects had free access to water and were maintained at approximately 85% of their 150 day old ad libitum weights, via post session feeding (Lab Diet Rodent Diet,

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30 Formula 5001; PMI Nutrition International, LLC; Brentwood, MO). The colony room was on a 12:12 hr light dark cycle (lights on from 8am 8 pm). Apparatus and Materials Eight Med Associates extra tall operant chambers (Model ENV 007; 30.48 cm L x 24.13 cm W x 29.21 cm H) were used to conduct experimental sessions. Chambers were contained in large sound attenuating boxes equipped with fans for ventilation. Intelligence panels, sidewalls, grid floors and drop pans were made of stainless steel; back walls, ceilings, an d doors were made of clear polycarbonate. Each intelligence panel contained a food receptacle (5 cm x 5 cm x 3 cm) that was equidistant between two levers (requiring approximately 0.31 N force), each of which measured 4.5 cm x 2 cm and were located 22 cm f rom the chamber ceiling. Seven cm above each lever were three light emitting diodes (LED; red, yellow, green; 0.8 cm in diameter, 0.7 cm apart from each other). On the wall parallel to the intelligence panel was a house light (28 volt), centered left to ri ght and 1.5 cm from the ceiling. Purified Rodent Tablets (45 mg sucrose food pellets ; TestDiet Richmand, IN ) were located outside of the chamber, but inside of the sound attenuating box in a circular pellet dispenser (Model ENV 203) A white noise genera tor was in the experimental room to mask extraneous sounds. Experimental events and data collection took place on a computer in the same room, using Med PC software and hardware (MED Associates). On drug delivery days, nicotine ([ ] Nicotine Hydrogen Tartr ate Salt; Sigma, St. Louis, MO), dissolved in a potassium phosphate buffered saline was used. Procedure All sessions were conducted on separate days, seven days per week, at approximately the same time during the light cycle each day. A 10 min blackout p eriod preceded each session, during which lever presses did not have any programmed consequences, but were recorded. The

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31 pre session blackout period was implemented to allow for nicotine absorption in subjects receiving nicotine during the Drug Administrat ion condition (described in more detail below). Figure 2 1 shows a schematic of the progression of conditions that are described in the sections that follow. Pre tests. All pre test conditions were conducted before subjects had experience earning food for pressing levers. The first pre responding in the presence of the stimuli that were to be used later in the observing response After the blackout period, the houselight was illuminated for 10 additional minutes. The houselight was either blinking (0.3 sec on, 0.3 sec off) or continuously illuminated, alternating every 2 min between the two stimulus types. Lever presses during this 10 min period did not have programmed consequences but were recorded. Operant Evaluation tests were conducted for two consecutive sessions. Next, responding was evaluated when the consequence for pressing the levers consisted of turni ng on a blinking or continuous houselight. Hereafter, this condition will be referred to as which one lever was designated as the blink lever and the other lever was designated as the continuous lever (counterbalanced across subjects). One response on the blink lever resulted in 10 sec of a blinking houselight (additional responses on either lever during this 10 sec period did not have programmed consequences, but were recorded), whereas one response on the continuous lever resulted in 10 sec of a continuously illuminated houselight. A response only illuminated the appropriate stimulus when there was no stimulus being presented at the time of the response. The lever assignments remained the same for the first two days of Stimulus

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32 Evaluation (e.g., left blink, right continuous), and were switched for the third and final day (e.g., left continuous, right blink) to assess whether side biases had developed. Lever traini ng. The day after the final pre test session, research assistants trained lever pressing by giving subjects 45 mg sucrose pellets when successive approximations of lever pressing were made. These initial training sessions ended after 30 min or after 20 res ponses on each lever. One response resulted in a food pellet, with the exception that after three consecutive responses on the same lever food could only be earned by pressing the other lever. Hand shaping continued for up to three additional sessions, as needed. Once lever pressing was acquired, rats continued to earn food for pressing levers but were required to strictly alternate between the two levers such that the second consecutive response on one lever did not result in food. These alternation sessio ns lasted for a maximum of 30 min or until 30 responses had been made on each lever, on seven separate days. The houselight was continuously illuminated during all lever training sessions. Discrimination training. After rats were trained to press both lev ers, the Discrimination Training condition began. During the last minute of the blackout period, all three LEDs above each lever were illuminated to signal the beginning of the session. The LEDs turned off after 1 min and the houselight was simultaneously illuminated, either blinking or continuous (component type was randomly determined at the beginning of each session). Components alternated between a continuously illuminated houselight (S+) which signaled periods when food was available for pressing the l eft food extinction, lever (i.e., food components) and a blinking houselight (S ) which signaled periods when food was not available for pressing the food extinction lever (i.e., extinction components). Initially, the first response on the food extinction lever after an average of 15 sec (i.e., variable interval 15 sec [VI 15]) resulted in a food delivery.

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33 After seven sessions, this value was increased to a VI 20 sec schedule of food delivery. VI distributions were composed of 15 values based on the Fleshl er Hoffman distribution (Fleshler & Hoffman, 1962). Compon ents lasted an average of 60 sec (rectangular distribution ranging from 10 to 110 sec); however, if the extinction component was scheduled to change to a food component, it would not change until 5 sec elapsed without a response on either lever (i.e., differential reinforcement of other behavior [DRO] 5 sec). The DRO procedure was implemented to prevent adventitious pairings between responding during extinction components and subsequent transitions t o food components. Aside from the DRO contingency, responses on the right observing, lever did not have any additional programmed consequences during Discrimination Training. Discrimination Training lasted a minimum of 65 days and until all but two subjec ts displayed a discrimination index (DI) of 0.75 or higher. Discrimination index was calculated by taking the rate of responding on the food extinction lever in the presence of the S+, divided by the sum of the rate of responding on the food extinction lev er in the presence of the S+ and S Values could range from zero to unity, with higher values indicating greater stimulus control. Two subjects (R223 and R224) did not reach the 0.75 DI criterion. The DRO requirement was then increased from 5 to 10 second s for these two subjects. This effectively increased DI (0.53 to 0.73 for R223; 0.59 to 0.66 for R224). Because of this improvement, all subjects were moved to the next condition. Observing response procedure. The DRO contingency was discontinued when t he observing response procedure began. During the last minute of the blackout period, all three LEDs above each lever were illuminated to signal the beginning of the session. At the end of one minute, the LEDs turned off making the chamber dark. At the beg inning of the session, the

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34 computer randomly determined whether a VI 20 sec food or extinction component would be in effect; however, the stimulus corresponding to the selected component was only shown contingent on a response to the right observing lever Initially, only one response (i.e., FR 1) on the observing lever was required to illuminate the schedule correlated stimulus for 10 sec If a component was scheduled to end during the 10 sec stimulus presentation, the component continued until the stimul us turned off. Immediately after the stimulus turned off the schedule change d For example, if after 5 sec of S+ stimulus presentation the food component was scheduled to switch to extinction, the S+ and food schedule would remain in effect for the final 5 sec of the stimulus presentation and the component would immediately change to extinction when the stimulus turned off. For the first five sessions of the observing response procedure, the first five observing responses resulted in the S+ stimulus being presented. If the extinction component was in effect when one of the first five responses occurred, the component switched to VI 20 sec food (Shahan, 2002). Otherwise, components alternated every 60 sec on average as described for Discrimination Training. After 11 sessions under the conditions described above, the VI 20 sec food schedule was increased to a VI 30 sec food schedule. Ten sessions later the observing response requirement was increased from FR1 to VI 5 sec. Thus, the terminal parameters of the observing response procedure consisted of a VI 30 sec food schedule alternating with extinction approximately every 60 sec, and stimuli were presented for 10 sec on a VI 5 sec schedule. Unless otherwise noted, all sessions from this point forward were arr anged according to these terminal parameters and were 30 min in duration. Subjects experienced the terminal parameters for 26 sessions, after which they were stratified into three groups of six based first on observing response rate, second on DI, and thi rd,

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35 when possible, on food extinction response rates in the presence of the S+ and S The three groups differed with respect to the dose of nicotine administered during all subsequent conditions: Vehicle (0 mg/kg nicotine), 0.3 mg/kg Nicotine (base), or 0.56 mg/kg Nicotine (base). Drug administration. For 70 sessions, subjects received daily pre session subcutaneous injections of the dose they were assigned. The 70 session Drug Administration condition was divided into four sections for the purposes of c larity and data analysis: Acute administration (sessions 1 5), Chronic administration (sessions 31 35), Resistance to Extinction (sessions 36 40), and Extended Chronic administration (sessions 66 70). Everything operated as normal during the Resistance to Extinction sessions, except that food was no longer delivered during food components. After five sessions food was reintroduced. Data Analyses. One subject in the Vehicle group never acquired the observing response, defined as an increase in observing responses relative to the Stimulus Evaluation pretest condition. Thus, this subject was eliminated from all analyses, leaving the Vehicle group with n = 5. To investigate responding during the pretest conditions, a repeated measures ANOVA was conducted on the left and right levers during the Operant and Stimulus Evaluation conditions. Because of repeated measurement, all results were adjusted for sphericity using Huynh Feldt correction (Huynh & Feldt, 1976 ). An additional ANOVA was conducted on mean right lever response rates during the Operant Evaluation, Stimulus Evaluation, the last five sessions of Discrimination training, and the first five sessions of the Observing Response hoc analyses were performed when significant main effects were found.

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36 ANOVAs were also performed to determine whether there were significant differences across the three drug administration groups (Vehicle, 0.3 Nicotine, 0.56 Nicotine) just prior to the Drug Administration condition in mean DI, observin g response rates, and food extinction response rates in the presence of the S+ and S To determine whether there were differences across groups during the Acute, Chronic, Resistance to Extinction, and Extended Chronic sections of the Drug Administration condition, ANOVAs were conducted, with Huhyn hoc analyses were performed when significant main effects were found. Finally, to evaluate the presence of rate dependent effects, linear regression analyses were perform ed on the log percentage of pre drug response rates graphed as a function of the log pre drug response rates during the Acute, Chronic, and Extended Chronic sections of the Drug Administration condition. All response types (i.e., observing, responses maint ained by food, and responses during extinction) were included in the same graph to generate a suitable amount of variability in pre drug response rates to assess rate dependence. All results were deemed statistically significant at p < 0.05. Results Beca use subjects had not yet been divided into groups during the pretest conditions, these conditions were evaluated with all subjects considered as one group. Response rates (resp/min) were low on both the right and left levers during the two days of Operant Evaluation (mean + SEM right lever = 0.25 0.04 resp/min; left lever 0.15 0.03 resp/min). Response rates increased on both levers during the Stimulus Evaluation pretest (mean + SEM right lever = 0.85 + 0.12 resp/min; left lever = 0.67 + 0.10 resp/min). There was a significant difference across conditions (F (1,83) = 28.48), but there was no significant difference in response rates between the two levers and there was no lever x condition interaction.

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37 Because there was no difference in responding betwee n the right and left levers, Figure 2 2 shows only responding on the right lever, which later became the observing lever. The first two panels of Figure 2 show the mean and standard e rror of the mean ( + SEM) for all subjects during the pretests. The third panel of Figure 2 2 shows responding during the last five days of Discrimination Training. The only consequence for pressing the lever during this condition was the DRO contingency tha t prevented transition from the extinction to the food component. Response rates during the last five days of the Discrimination Training condition averaged 0.78 resp/min ( + SEM = 0.08), and were not significantly different from response rates during the St imulus Evaluation pretest. Fina lly, the fourth panel of Figure 2 2 shows the rates of responding during the first five days of the Observing Response condition. Response rates increased during this condition to an average of about 4.02 resp/min ( + SEM = 0.2 3). There was a significant difference across conditions (F (3,251) = 114.1) and post hoc analyses revealed that responses during the first five days of the Observing Response condition were significantly higher than the three previous conditions, which we re not significantly different from each other. Mean DI, observing response rate, and food extinction response rates in the presence of the S+ and S were computed based on the last five sessions of the Observing Response condition, just prior to the Drug Administration condition, for each subject in a group. These sessions were used to determine group assignment and the means and SEMs for each group are shown in Table 2 2 There were no significant differences between groups on any of the measures. Figur e 2 3 shows mean ( + SEM) food extinction response rates du ring S+ components (top graph ) an d S components (middle graph ), as well as observing response rates (bottom

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38 graph ). Table 2 3 displays the means ( + SEM) of the response rates displayed in Figure 2 3 Figure s 2 4, 2 5, and 2 6 show response rates for individual subject s on the Food Extinction lever in the presence of the S+, S and Observing lever respectively, with a different subject in each individual graph and groups organized in columns (from lef t to right: Vehicle 0.3 Nicotine 0.56 Nicotine ) All of the graphs in Figures 2 3 through 2 6 are organized the same, with the first panel of each graph showing the last five sessions of the pre drug condition, the second panel showing the acute sessions the third panel showing the chronic sessions, and the fourth panel showing the extended chronic sessions. The top graph in Figure 2 3 shows that food extinction response rates in the presence of the S+ were high for all groups during the pre drug conditi on, and there were no significant differences across groups. Response rates in the presence of the S+ remained high throughout the three Drug Administra tion sections shown in Figure 2 3 and there were no significant differences in response rates across gr oups during any of the sections. The middle graph in Figure 2 3 illustrates that food extinction response rates during S presentations were lower during the pre drug condition than food extinction response rates during S+ presentations, but again there w ere no significant differences across drug administration groups. During the Acute Drug Administration section there was a significant difference across groups (F (2,81) = 4.472) and post hoc analyses revealed that the 0.3 Nicotine group responded signific antly more than the Vehicle and 0.56 Nicotine groups (Table 2 3 ). There were also significant differences in response rates across groups during the Chronic Drug Administration section (F (2,81) = 3.35). However, unlike during the Acute section, during th e Chronic section post hoc analyses revealed a marginally significant (p=0.05) increase in the 0.56 Nicotine group. Finally, there were significant differences in response rates across groups during

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39 the Extended Chronic Drug Administration section (F (2,81 ) = 3.69). Post hoc analyses revealed that the Vehicle group responded significantly more than the 0.3 Nicotine group, but not more than the 0.56 Nicotine group. There were no significant differences between the 0.3 and 0.56 Nicotine groups. The bottom gr aph in Figure 2 3 shows that observing response rates during the pre drug condition were similar across groups (also see Table 2 3 ). Acute nicotine administration resulted in a significant difference across groups (F (2,81) = 7.25), and post hoc analyses r evealed that response rates for the 0.3 Nicotine group were significantly higher than response rates for both the Vehicle and 0.56 Nicotine groups. Similarly, there were significant differences across group during the Chronic Drug Administration section (F (2,81) = 6.58). During Chronic, however, post hoc analyses revealed a significant increase in response rates for both the 0.3 and the 0.56 Nicotine groups, relative to the Vehicle group. This significant increase in response rates continued (F (2,81) = 13 .62) for both groups after extended exposure to nicotine. It is worth noting that there was a decreasing trend in observing responses across the last five sessions of the Chronic section for the 0.3 Nicotine group ; however, after Resistance to Extinction o bserving responses increased and remained stable at this higher rate. The mean effects shown in Figure 2 3 are consistent with the majority of the individual subject effects shown in Figures 2 4 through 2 6 for each response type. The Chronic Drug Administ ration section immediately preceded the five days of Resistance to Extinction. Because response rates were different across groups for each of the three responses during the Chronic section, it was necessary to control for these differences to evaluate res istance to extinction (Nevin, 1974). Figure 2 7 shows that, as expected, all three response types decreased across the five days of Resistance to Extinction. There were no

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40 significant differences in the proportions of food extinction responding in the pres ence of the S+ (top graph ) or in the proportions of obse rving responses (bottom graph ) across the five extinction sessions. There were also no significant differences in the food extinction proportions of responding in the presence of the S (middle graph ) during the first four days of extinction. On day five, there was a significant difference across groups (F (2,14) = 9.982) and post hoc analyses revealed that subjects in the Vehicle group had significantly higher proportions of responding than subjects in the 0.3 and 0.56 Nicotine groups (mean + SEM Vehicle = 0.38 + 0.04; 0.3 Nicotine = 0.18 + 0.05; 0.56 Nicotine = 0.13 + 0.03). To examine rate dependent effects, scatter plots were created for each group of subjects. Pre drug response rates were calcula ted by averaging response rates during the last five sessions of the Observing Response procedure that immediately preceded the Drug Administration condition. Log percentage of pre drug rates were calculated and graphed as a function of log pre drug rates. Three separate plots were created for each condition across the three groups, with all of the response types (i.e., observing, food extinction S+ and S ) included in each plot, as shown in Figure 2 8 Lines were fitted to the data by least squares regress ion and the fitted parameter values for the slope and y intercept, as well as the r 2 value, for each line is shown in Table 2 4 There were seven instances, out of nine, in which the fitted slopes were significantly different from zero: a positive slope fo r the Vehicle group during the Chronic section, and negative slopes for the 0.3 and 0.56 Nicotine groups during all three sections. Discussion E xperiment 1 support s the MEO account by showing that nicotine increased responding maintained by conditioned rei nforcers (i.e., visual stimuli that had been associated with food availability). Extended, repeated exposure to nicotine more than doubled the number of

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41 responses per 30 min session from approximately 125 responses, seen with the Vehicle group, to over 250 responses, seen with the two nicotine groups (see Table 2 3 ). The increases in the present study were reliable and robust, and sustained changes in responding over the course of the experiment were specific to responses maintained by conditioned reinforce rs. That is, nicotine did not reliably increase responding maintained by food reinforcers at any point, and any increases in responding during extinction (e.g., 0.3 Nicotine during Acute and 0.56 Nicotine during Chronic) were not sustained. To investigate further the MEO account of nicotine, resistance to extinction was compared across groups of rats given nicotine or vehicle. If nicotine increased the reinforcing value of the conditioned reinforcers, then this should have resulted in a context with a riche r amount of reinforcement relative to the vehicle control group. According to behavioral momentum, responses occurring in the context of a richer amount of reinforcement should be more resistant to extinction (Nevin, 1974; Nevin & Grace, 2000). Instead, ni cotine did not affect resistance to extinction on any of the response types studied. Several possibilities might account for this lack of effect. One possibility is that nicotine did not serve as a MEO in the present study, and that the increases in observ ing responses were due to a different mechanism. One alternative mechanism that has been discussed is that nicotine generally increases lever pressing because of its effects on activity (Frenk & Dar, 2004). However, responding during extinction serve d as a control for detecting general increases in motor capacity, and nicotine did not increase responding during extinction. On the other hand, a lack of effect of nicotine on resistance to extinction may have been due to limitations in the behavioral momentum account of resistance to extinction. The current study was designed to compare resistance to extinction across subjects, whereas behavioral

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42 momentum theory has been almost entirely developed by comparing resistance to extinction within subjects and within sessions. The typical paradigm for studying behavioral momentum is to use a multiple schedule comprised of a rich and lean schedule, with greater resistance to extinction in the rich relative to the lean schedule (for a review see Nevin & Grace, 2000). In fact, one study was unable to demonstrate greater resistance to extinction in a rich relative to a lean schedule when resistance was compared across conditions or sessions with simple schedules of reinforcement, rather than within the same session (Cohen, Riley, Weigle, 1993). Furthermore, it has not yet been demonstrated that higher rates of conditioned reinforcement will necessarily result in greater resistance to extinction, as it occurs with higher rates of primary reinforcement. Shahan and Podelsnik (2005) used a complex multiple observing response procedure, whereby a rich component resulted in a higher rate of conditioned reinforcement, contingent on observing responses, relative to a lean component. Observing response rates were higher in the rich component, but subjects did not demonstrate greater resistance to extinction in the rich component relative to the lean component. The authors explained that two levels of conditioning would need to take place for resistance to occur with conditioned reinf orcers: (1) pairings between the primary reinforcers and the stimuli that are being established as conditioned reinforcers and (2) pairings between the higher rate or amount of conditioned reinforcers and the context in which they occur. The same can be sa id of the current study in that the visual stimuli were being paired with food during S+ presentations, and subjects in the two nicotine groups presumably experienced an experimental context with a larger amount of reinforcement than subjects in the Vehicl e group. At this time it is not clear whether the behavioral momentum theory of resistance to extinction applies to such second order levels of conditioning because of a general lack of research designed to study such phenomena.

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43 The present study also had the advantage of generating a range of response rates, making it possible to evaluate whether nicotine produced rate dependent effects ( Table 2 4 and Figure 2 8 ). Of the nine regression analyses, six resulted in negative slopes that were significantly diff erent from zero (increases in low pre drug rates and decreases in high pre drug rates). It is important to note that there was never more than 21% of the variance accounted for by the linear equations as indicated by the r 2 values shown in Table 2 4 Neve rtheless, the data do suggest a tendency for rate dependent effects of nicotine. Finally, pretests w ere conducted to determine whether the illumination of a continuous and blinking houselight would function as a primary reinforcer, similar to what other re searchers have demonstrated ( Barry & Symmes, 1963; Goodrick, 1970; Kiernan, 1965; Marx, Henderson, Roberts, 1955; Roberts, Marx, Collier, 1958; Robinson, 1959; Segal, 1959; Tapp, Mathewson, Simpson, 1968; Stewart, 1960 ) and whether the stimuli would later come to function as conditioned reinforcer s There was indeed, an increase in lever pressing during the Stimulus Evaluation condition, relative to the Operant Evaluation condition suggesting a weak primary reinforcing function of the stimuli During Dis crimination Training the stimuli were associated with a multiple schedule of food and extinction conditions which have been shown to establish stimuli as conditioned reinforcers (Dinsmoor, 1983). During the first five days of the Observing Response condi tion, responses that turned on a houselight increased to more than four times the response rates seen during the Stimulus Evaluation condition. In fact, observing response rates continued to increase with extended exposure to the procedure ( compare Figure s 2 2 and 2 3 ). The increases were not simply due to the presence of food during the sessions, which may have caused some arousal (Killeen, Hanson, Osborne 1978), because there were no significant

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44 increases during Discrimination Training. This finding sugge sts that the stimuli were established as conditioned reinforcers.

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45 Table 2 1. Hypothetical effects of nicotine on responding maintained by each of the response types investigated with the observing response procedure Outcome Response #1 #2 #3 #4 Food extinction (S+) -Food extinction (S ) ---Observing -

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46 Table 2 2. Mean + SEM DI, Observing response rate, food extinction response rates in the presence of the S+ and S from the five ses sions prior to the Drug Administration condition Group D.I. Observing Food extinction (S+) Food extinction (S ) Vehicle 0.73 + 0.02 5.63 + 0.5 3 37.62 + 1.01 14.68 + 1.65 0.3 Nicotine 0.73 + 0.02 6.21 + 0.97 37.34 + 3.34 15.97 + 2.34 0.56 Nicotine 0.74 + 0.02 5.62 + 0.76 47.31 + 5.54 16.09 + 1.47

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47 Table 2 3. Mean + SEM response rates just prior to and during the Drug Administration condition for food extinction response rates in the presence of the S+ and S and for observing responses Pre Drug Acute Chronic Extended Chronic Food Extinction (S+) Vehicle 37.62 + 1.01 41.27 + 1.32 46.59 + 2.92 46.54 + 2.31 0.3 Nicotine 37.34 + 3.34 45.24 + 3.54 38.88 + 2.56 42.84 + 2.11 0.56 Nicotine 47.31 + 5.54 34.45 + 4.14 38.83 + 2.27 42.13 + 2.50 Food Extinction (S ) Vehicle a 14.68 + 1.65 a 15.20 + 1.82 a 12.07 + 1.90 c 15.53 + 1.55 e 0.3 Nicotine a 15.97 + 2.34 a 22.78 + 2.48 a b 11.74 + 0.99 d 11.33 + 0.9 4 e 0.56 Nicotine a 16.09 + 1. 47 a 15.87 + 1.45 b 15.97 + 1.05 c d 14.54 + 0.98 Observing Responses Vehicle b 5.6 3 + 0.5 3 b 5.52 + 0.48 a 4.65 + 0.52 c d 4.25 + 0.38 e f 0.3 Nicotine b 6.21 + 0.97 b 9.69 + 1.05 a b 7.32 + 0 .89 c 7.99 + 0.69 e 0.56 Nicotine b 5.62 + 0.76 b 5.84 + 0.86 b 8.19 + 0.56 d 9.02 + 0.77 f Note: Within each response type, v alues in each column indicated by the same superscripted letter (e.g., a ) were significantly different from each other with p < 0.05.

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48 Table 2 4. Fitted parameter values and corresponding r 2 for each linear regression applied to the rate dependent graphs shown in Figure 2 8. Phase Group Slope y intercept r 2 Acute Vehicle 0.16 102 0.0 1 0.3 Nicotine* 2.30 211 0. 15 0.56 Nicotine* 2.00 176 0. 06 Chronic Vehicle* 1.27 71 0. 12 0.3 Nicotine* 0.8 1 25 0. 08 0.56 Nicotine* 3.2 252 0. 16 Extended Chronic Vehicle 0.53 99 0.01 0.3 Nicotine* 1.8 169 0.21 0.56 Nicotine* 3.7 282 0.13 Note: Asterisks denote slopes that were significantly different from zero. Vehicle: Chronic F (1,73) = 9.9; 0.3 Nicotine: Acute F (1,88) = 16.67; Extended Chronic F (1,88) = 24.02 0.56 Nicotine: Acute F (1,84) = 11.74; Chronic F (1,88) = 164.53; Extended Chronic F (1,88) = 82.4

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49 Figure 2 1. Experiment 1 schematic. Shows the progression of conditions throughout the experiment. Vertical lines indicate the beginning of a condition a nd the number below the line is the approximate session number. Bracketed areas indicate different sections within the observing response procedure that were subjected to statistical analyses.

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50 Figure 2 2. Pretests. Mean + SEM res p/min for all subjects are shown. The first two panels show resp/min on the right (future observing) lever during the Operant and Stimulus Evaluation pretests. The third and fourth panels show resp/min on the right lever during the last five sessions of Di scrimination Training and the first 5 days of the Observing Response procedure, respectively. The third and fourth panels represent 10 consecutive sessions.

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51 Figure 2 3. Mean ( + SEM) Food Extinction S+, S and Observing Responses for the Vehicle group (filled circles), the 0.3 Nicotine group (open circles), and the 0.56 Nicotine group (open squares). The first panel of each graph shows the last five sessions of the Observing Response condition, immediately preceding the Drug Administration condition. The next three panels represent five sessions from three of the sections of the Drug Administration condition: Acute, Chronic, Extended Chronic. The top graph (a) shows resp/min on the food extinction lever in the presence of the S+ (i.e., food maintained responses). The middle graph (b) shows resp/min on the food extinction lever in the presence of the S (i.e., responses during extinction) and the bottom graph (c) shows resp/min on the observing response lever Note different y axes for each of the three response types. Food Extinction Res ponses (S+)

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52 Figure 2 4. Individual subject data showing Food Extinction responses on the S+ for the last five sessions of the Pre Drug, Acute, Chronic, and Extende d Chronic sections. Each graph is a different subject, with drug administration group organized in columns, from left to right, showing the Vehicle (filled circles), 0.3 Nicotine (open circles), and 0.56 Nicotine groups (filled triangles), respectively Food Extinction Responses ( S+ ) Food Extinction (S + )

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53 Figure 2 5. Individual subject data showing Food Extinction responses on the S for the last five sessions of the Pre Drug, Acute, Chronic, and Extended Chronic sections. Each graph is a different subject, with dr ug administration group organized in columns, from left to right, showing the Vehicle (filled circles), 0.3 Nicotine (open circles), and 0.56 Nicotine groups (filled triangles), respectively 0.56 Nicot ine g roup Food Extinction Responses ( S ) Food Extinction (S )

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54 Figure 2 6. Individua l subject data showing Observing responses for the last five sessions of the Pre Drug, Acute, Chronic, and Extended Chronic sections. Each graph is a different subject, with drug administration group organized in columns, from left to right, showing the V ehicle (filled circles), 0.3 Nicotine (open circles), and 0.56 Nicotine groups (filled triangles), respectively. Observing Responses Observing

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55 Figure 2 7. Resistance to Extinction. Mean + SEM proportion of Chronic resp/min for subjects in the Vehic le group (filled circles), the 0.3 Nicotine group (open circles), and the 0.56 Nicotine group (open squares). The top graph (a) shows proportion of Chronic resp/min on the food extinction lever in the presence of the S+ (i.e., food maintained responses). T he middle graph (b) shows proportion of Chronic resp/min on the food extinction lever in the presence of the S (i.e., responses during extinction) and the bottom graph (c) shows proportion of Chronic resp/min on the observing response lever. The dotted li ne at 1.0 indicates no change from Chronic, with values above and below the line indicating increases and decreases, respectively.

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56 Figure 2 8. Rate dependent scatterplots. Rate dependent scatter plots for the Vehicle (left column), 0.3 Nicotine (middle column), and 0.56 Nicotine (right column) Groups. Shown are the log percentage of pre drug response rates plotted as a function of log pre drug response rates for the Acute (top row), Chronic (middle row), and Extended Chronic (bottom row) sections. All t hree response types are shown together on each plot observing (filled triangles), food extinction S+ (filled circles), and food extinction S (open circles). Equations, with the fitted parameter values and r 2 can be found in Table 2 4

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57 CHAPTER 3 Experi ment 2 Introduction The results of the Stimulus Evaluation condition of Experiment1 showed that rates of responding increased slightly relative to the operant level, when the visual stimuli were made contingent on a response. This finding suggested that t he stimuli may have initially functioned as weak or moderate primary reinforcers. It is important to note, however, that the Operant and Stimulus Evaluation sessions were brief (10 min) and were only conducted over a five day period to avoid over exposure and perhaps conditioned inhibition to the stimuli that would later be used as conditioned reinforcers (Lubow & Moore, 1959). It is possible that the increases seen during the Stimulus Evaluation condition were due to general increases in lever pressing that would have occurred over time, regardless of the consequences arranged. Thus, although the data suggested that the stimuli did serve a primary reinfo rcing function, this conclusion was only tentative. Other researchers have suggested that under some conditions visual stimuli can function as weak or moderate primary reinforcers ( Barry & Symmes, 1963; Goodrick, 1970; Kiernan, 1965; Kish, 1966; Marx, Henderson, Roberts, 1955; Roberts, Marx, Collier, 1958; Robinson, 1959; Segal, 1959; Tapp, Mathewson, Si mpson, 1968; Stewart, 1960 ). A recent study compared groups of rats to determine the effects of pre session injections of nicotine on responding maintained by two visual stimuli that generated different levels of responding: (a) turning off the houselight in an operant chamber for 5 sec, which resulted in approximately 35 responses during a 60 min session, and (b) turning on a stimulus light in an operant chamber for 5 sec, which resulted in approximately 10 responses during a 60 min session (Palmatier et a l. 2007). N icotine administration increased responding in the group of rats whose behavior was maintained by

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58 turning off the houselight to about 100 responses per session, but there were no significant increases in responding in the other group of rats w hose behavior was maintained by turning on the stimulus light. A ll rats in the study were initially trained to press the active lever using food as a consequence for pressing, in the same way that active lever responses are typically trained in nicotine se lf administration studies ( Caggiula et al., 2001; Chaudri et al., 2006; Donny et al., 2003 ). As discussed earlier, Frenk and Dar (2004) posited that lever training history may contribute to the nicotine induced increases seen only on the active lever. Thus a more systematic investigation of lever training history is warranted. Purpose of Experiment 2 Experiment 2 sought to: (1) explore the putative primary reinforcing function of the visual stimuli used in Experiment 1 (i.e., turning on a houselight), as well as the visual stimuli used in a number of nicotine self administration studies (i.e., turning off a houselight; Caggiula et al., 2002 ; Palmatier et al, 2007 ), (2) determine whether different histories of lever training would influence the apparent pr imary reinforcing effects of the visual stimuli (3) assess whether nicotine would have different effects on responding, as a function of lever training history and the type of visual stimulus (turning on versus turning off the houselight) and (4) further investigate the rate dependent e ffects of nicotine The lever training protoco l and general procedural design w ere based on th e procedures used by Caggiula and colleagues (e.g., Caggiula et al., 2002b) to investigate nicotine self administration Such pro cedures consisted of food depriving subjects and then exposing them to two sessions of lever training with food reinforcers, then gradually increasing the FR schedule of contingent stimulus presentations (five sessions of FR1, five sessions of FR2, ending with a terminal FR5 schedule).

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59 Methods Subjects Eight experimentally nave male Long Evans rats (Harlan; Indianapolis, IN), maintained at 85% ( 326 408 g) of their 150 day old ad libitum weights, served as subjects. Subjects were housed in individual home cages with bedding, and received free access to water and post session supplemental rodent chow (Lab Diet Rodent Diet; Formula 5001). The colony room was on a 12:12 hour light dark cycle (light from 8am 8pm). Apparatus and Materials Sessions were conducte d in 8 Med Associates extra tall operant chambers. The operant chambers were identical to those used during Experiment 1 described earlier. Med PC software and hardware were used to program experimental events on a computer located in the experimental roo m. The computer also collected and stored data after each session. On drug delivery days, nicotine ([ ] Nicotine Hydrogen Tartrate Salt; Sigma, St. Louis, MO), dissolved in potassium phosphate buffered saline was used. Procedure Subjects were randomly as signed to one of two groups, differing only with respect to their lever training history. One group of subjects (n = 4) was trained to press both the right and that were illuminated in the chamber were the red LEDs located above each lever. Lever training took place on two separate days. Two Lever Training Day one of training consisted of research assistants delivering food for approximations of pressing either the right or left lever, until one response was made on

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60 each lever. From that point forward, one food pellet was delivered for each lever press, with the re striction that the same lever could not be pressed more than three consecutive times. The fourth, and all subsequent, responses on the same lever did not have any programmed consequences, until at least one response on the alternate lever was made. The fir st day of training lasted 30 min or until subjects earned 20 pellets for pressing each lever (i.e., 40 total pellets). The second day of training was identical to the first, except that there were no time limits and sessions ended after 37 pellets had been e arned for pressing each lever ( 74 total). One Lever Training. As with the Two Lever group, the first day of training began with research assistants delivering food for approximations of lever pressing, but for pressing the right lever only. This continu ed until one response was made on the right lever, after which only responses to the right lever were followed by food pellet delivery. Responses on the left lever never had programmed consequences. The first training day ended after 30 min or after 40 pel lets had been earned for pressing the right lever. The second training day was identical to the first, except that there was no time limit and sessions ended after 74 pellets had been earned for pressing the right lever. Lights On and Lights Off After le ver training, subjects in both the One Lever and the Two Lever groups experienced all of the same procedures. Sessions were conducted at approximately the same time during the light cycle seven days per week. To begin, a ll 6 LEDs were illuminated five sec onds after the subject was placed into the operant chamber. A single response on either lever, or 60 sec without any response, turned off the LEDs and began the 60 min session. The active lever wa s designated as the right lever At the beginning of th e ses sion the operant chamber was dark during the Lights On phase, whereas the operant chamber was lit by the houselight during the Lights Off phase. If no response was made on the active lever,

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61 subjects remained in a dark or lit operant chamber, depending on t he phase. Initially only one response on the active lever (i.e., fixed ratio [FR] 1) produced 10 s ec of the houselight turned on (Lights On) or off (Lights Off). Additional active lever responses during the stimulus presentation did not have any programmed consequences, nor did responses on the inactive lever, but all responses were recorded. After five sessions of FR1 stimulus presentation, the response requirement was increased to FR2 for an additional five sessions, after which the response requirement w as increased to a final value of FR5. A minimum of 10 sessions at FR5 were required before stability was evaluated. The total number of responses per 60 min session were deemed stable by visual inspection if there were no increasing or decreasing trends (i .e., five consecutive sessions with all responses moving in the same direction) and as long as the highest or lowest number of responses did not occur during one of the last three sessions. Conditions changed upon meeting the stability criteria or after a maximum of 30 sessions, whichever occurred first. Exposure to the Lights On and Lights Off phases was counterbalanced across subjects within a group, such that two subjects in each group were exposed to the Lights On phase first. The first phase for all subjects, regardless of whether it was Lights On or Lights Off, was an ABAB design (with the exception of two subjects, R251 from the Two Lever group and R257 from the One Lever group, for whom it was an ABABA and ABAC design, respectively). The A conditio ns were baseline with a FR5 schedule of stimulus presentation and without drug administration. The B conditions consisted of daily subcutaneous (s.c.) administration of 0.3 mg/kg nicotine (base). For subject R257 the C condition consisted of daily s.c. adm inistration of 0.56 mg/kg nicotine (base).

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62 Between phases subjects remained in their home cages for 7 days, but continued to be weighed daily and maintained at 85% of their ad libitum weights. At the beginning of phase 2, stimuli were again initially avai lable on a FR1 schedule and the FR requirement increased to 5, as described earlier. Because subject R257 was not responding, lever training was repeated for this subject over a two day period in the same way that it was described earlier. All of the other subjects pressed the levers reliably and thus did not need additional lever training. The second phase for all subjects consisted of an ABABAC design. For all but subject R257, the A and B conditions were the same as those just described for phase 1 and t he C conditions consisted of daily s.c. administration of potassium phosphate vehicle. The only difference for subject R257 was that the B conditions consisted of daily s.c. administrations of 0.1 mg/kg nicotine instead of 0.3 mg/kg. Data Analysis. Two, 2 x 2 x 6 repeated measure ANOVAs were conducted with lever training group (One Lever versus Two Lever), lever (active versus inactive) and condition (three baseline, two nicotine, one vehicle) compared for each phase (Lights On and Lights Off). An addition al ANOVA was conducted to compare phase (Lights On versus Lights Off), lever, and condition, regardless of group assignment. All results were adjusted for sphericity using Huynh Feldt corrections (Huynh & Feldt, 1976 ). To evaluate the presence of rate depe ndent effects, linear regression analyses were performed on the log percentage of pre drug responses graphed as a function of the log pre drug responses during the Lights On and Lights Off phases. Active and inactive responses were included on the same gra ph and three linear regression analyses were performed for each phase: (1) both active and inactive responses grouped together, (2) active responses only, and (3) inactive responses only. All analyses were deemed statistically significant at p < 0.05.

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63 Res ults At the completion of the experiment a computer malfunction was discovered for subject R251 during all but the first two conditions of phase 1 (Lights Off), making the data uninterpretable. Thus, only the first two conditions are shown and applied to t he data analyses for this subject during Light s Off. Table 3 1 displays the mean ( + SEM) proportion of responses allocated to the active lever during the two days of shaping and during each subsequent experimental condition. During shaping for the Two Leve r group, both levers were technically active; however the data are expressed as a proportion of the lever that became active in subsequent conditions. Two subjects in the Two Lever group (R252 & R253) responded about equally on both levers during shaping, while the other two subjects showed a slight preference for the lever that became inactive during subsequent conditions (R251 & R255). All of the subjects in the One Lever (R254, R256, R257, R258) group allocated more responses to the active lever than on the inactive lever during shaping During all of the remaining conditions, every subject, regardless of group assignment, allocated most of their responses to the active lever ( almost always 90% or more). Figure 3 1 shows the last five sessions per con dition for each subject during the Lights On phase. As indicated in Table 3 1, a greater number of responses were allocated to the active lever than to the inactive lever for every subject and every condition (mean + SEM: Active lever = 81.3 + 4.5, Inacti ve lever: 4.4 + 0.3) with the exception of subject R257 during the second nicotine condition (recall that this subject received a 0.56 mg/kg dose of nicotine during this condition) this difference was statistically significant (F (1,188) = 425.6). There was a significant effect of condition (F (5, 188) = 23.8), as well as a significant lever x condition interaction (F (5,188) = 23.6), with nicotine reliably increasing responses on the active lever

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64 (mean + SEM = 126.7 + 14.0), relative to baseline (mean + SEM = 51. 7 + 6.9) and vehicle conditions (mean + SEM = 65.2 + 11.0), but not reliably increasing responses on the inactive lever. There were no significant lever x group or lever x group x condition interactions. Likewise, Figure 3 2 shows the last five sessions per condition during the Lights Off phase. As during the Lights On phase, a greater number of responses were allocated to the active lever than to the inactive lever for every subject and every condition (mean + SEM: Active lever = 135.1 + 8.6, Inactive lever: 4.8 + 0.4), with the exception of the first baseline condition for subject R255 (F (1,188) = 375.0). Again, there was a significant effect of condition (F (5, 188) = 33.2) and a significant lever x condition interaction (F (5, 188) = 34.2), with nicotine reliably increasing active (mean + SEM = 228.3 + 26.6), but not inactive, responses relative to baseline (mean + SEM = 74.5 + 11.6) and vehicle (mean + SEM = 117.7 + 18.7) conditions. As before, there were no lever x group or lever x group x condition interactions. Furthermore, there was a significant lever x phase interaction (F (1, 378) = 52.9), whereby a greater number of responses occurred on the active lever during the Lights Off phase (mean + SEM = 135.1 + 8.7) than during the Lights O n phase (mean + SEM = 81.3 + 4.5). Figures 3 3 and 3 4 are cumulative response records for one representative rat from each group (R252 and R258) during the Lights On and Lights Off phases, respectively. Each row for a subject shows the final session from a condition. Deflections in the record represent the beginning of the 10 sec stimulus presentation, and the pen resets at the end of the 10 sec. Responses that occur red after the deflection took place during the stimulus presentation. In both phases, the slopes bec a me steeper during nicotine conditions, relative to baseline and vehicle conditions. Additionally, pauses between responses appear ed to be less frequent and shorter in duration during nicotine conditions. It is also important to note that during all conditions, it wa s

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65 rare for a response to occur during the sti mulus presentation. Table 3 2 shows the proportion of stimulus presentations during which at least one response occurred (active or inactive). For most subjects under most conditions, less t han 40% of the stimulus presentations contain ed a response. One subject, R251, was more likely than all the other subjects to respond during a stimulus presentation. The cumulative response records also revealed two distinct patterns of responding during nicotine administration conditions, which warranted further investigation. One pattern was an increase in response rates during the first 5 10 min of the session that diminished during the remainder of the session, as seen for both subjects during the Ligh ts On phase (Figure 3 3). The other pattern was a constant high rate of responding throughout the entire session, as seen during both nicotine conditions for R258 and the second nicotine condition for R252 during Lights Off (Figure 3 4). All other subject s, except R257, showed one or both of these patterns during nicotine administration conditions. Time course analyses were conducted on all of the last five sessions of each condition for both the Lights On and the Lights Off phase s to further investigate t hese patterns. Because there were no differences between lever training groups, all subjects were evaluated as one group. Furthermore, because post hoc analyses and visual inspection of the data did not reveal a significant difference across subsequent exp osures to a particular condition (e.g., the first versus the second exposure to baseline), such conditions were collapsed into one. Shown in Figure 3 5 are the mean ( + SEM) number of responses during each 2 min bin of the 60 min session. Figure 3 5 shows that there is a peak in responding on both the active and inactive lever during the first 10 min of the session, regardless of phase. The peak in responding during this early portion of the session increased substantially during the nicotine conditions, bu t only on the active lever.

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66 During the Lights On phase, nicotine induced increases in responding occurred throughout the entire session. Although responding remained elevated, relative to baseline levels, there were no differences in responding between ni cotine and vehicle during the last 10 min of the session because of increases in responding during the vehicle condition. During the Lights Off phase, the nicotine induced increases became stable after approximately 10 min and remained well above baseline levels for the remainder of the session. Again, responding increased during the vehicle condition during the last 20 min of the session, such that by the end of the session levels were just slightly less than those seen during the last 20 min of the nicot ine conditions. Although there was a similar peak in responding occurred during the first 5 10 min of the session on the inactive lever, the total number of responses was very low (not e the difference in scales). There was a general tendency for responding to be higher during the nicotine conditions; however, these increases were not reliably present during the session and were small in magnitude. Finally, to examine rate dependent effects scatter plots were created for each phase. Pre drug responses were calculated by averaging responses during the last five sessions of the baseline conditions that immediately preceded the nicotine conditions. Log percentage of pre drug response rates were calculated and graphed as a fu nction of log pre drug response rates for both the active and inactive lever, with both responses shown on the same graph. Lines were fitted to the data three separate times for each phase, using least squares regression, and the fitted parameter values (slope and y intercept) for each line a re shown in Table 3 3 as well as the percentage of variance accounted for by the line ( r 2 ). The first line for each phase was fitted to both active and inactive responses together, which did not result in slopes that were significantly different from zero for either phase. The second line was fitted to the active lever only, and for

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67 both phases the slope was negative and significantly different from zero. Finally, the third line was f itted to the inactive lever only, and again the negative slopes were sign ificantly different from zero during both phases Discussion Experiment 2 showed that visual stimuli, turning on and turning off a houselight, function ed as primary reinforcers for rats. Regardless of whether s ubjects were initially trained to p ress one or both levers, all subjects eventually showed a strong preference for the active lever. It is important to note that during lever training, subjects who were trained to press both levers allocated their responses equally across the two levers, until food w as removed and stimulus changes were presented contingent on active lever responses only (Table 3 1, subjects R251, R252, R253, and R255). Thus, visual stimulus change as a consequence in its own right engendered preference for the active lever for a group of rats who were trained to press both levers equally often This finding suggests that the visual stimuli used in the present study functioned as primary reinforcers. An alternative account regarding the responses occurring in Experiment 2 is that visua l stimulus change elicited responses, rather than reinforced responses. There are at least two lines of evidence that make the elicitation account implausible. First, if the stimuli elicited lever pressing then they should have been just as likely to elici t inactive responses as they were to elicit active responses, especially for the Two Lever training group. Second, this account becomes even less likely when examining Table 3 2 and the cumulative records of Figures 3 3 and 3 4, which all show that when th e stimuli we re present, responding wa s not likely to occur. The mean proportion of stimuli that contained a response averaged around 0.32 in other words, during almost 70% of stimulus presentations no response was made. Furthermore, even with the

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68 reliabl e, pronounced increases in responding during nicotine conditions, there were no consistent changes (increases or decreases) in the proportion of stimuli that contained a response. The present study also had the advantage of generating a range of response rates across the active and inactive levers making it possible to evaluate whether nicotine produced rate dependent effects ( Table 3 3 and Figure 3 6 ). When active and inactive responses were evaluated with a single regression analysis, the slopes were no t statistically significant during either phase. However, when active and inactive response rates were analyzed separately, the negative slopes ( increases in low pre drug rates and decreases in high pre drug rates) were significantly different in all four cases. It is important to point out that on the inactive lever, regardless of the phase there were increases at the low pre drug rates and decreases at the high pre drug rates Alternatively, on the active lever there were only a few instances of response s decreasing, all of which were during the Lights Off phase with subject R257 (recall that this subject did not show nicotine induced increases in responding at any time during this phase ) Ot herwise, active lever response rates only increased but to a g reater extent proportionally, with low er pre drug rates than with high er pre drug rates. Similar to Experiment 1 Table 3 3 shows that the percentage of variance accounted for by the linear regression s were small, in this case never exceeding 1 2 %. Nevert heless, as with Experiment 1, the data do suggest a tendency for rate dependent effects of nicotine. T he r esults from Experiment 2 provide additional support for the MEO account of nicotine by showing that responding ma intained by primary reinforcing visua l stimulus changes increased when nicotine was delivered. Similar increases were not noted on the inactive lever, even for subjects who were initially trained to press the inactive lever with food as a consequence (Two Lever group). Nicotine increased resp onding maintained by both types of

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69 stimulus change (Lights On and Lights Off). The absolute increases in responding in the Lights Off phase of the current study were comparable with the increases noted by other researchers (Donny et al., 2003; Palmatier et al., 2007). However, the increases seen in the current study during the Lights On phase are c ontrary to the findings by Palmatier et al (2007), who only saw increases in responding maintained by turning off the houselights. The current study involved turn ing on the houselight, from a dark chamber, whereas Palmatier et al. had subjects turning on a stimulus light located above the lever. Furthermore, the current study maintained a greater number of responses per session during the Lights On phase than were seen in the light s on group in the Palmatier et al study Indeed, stimulus intensity has been found to affect the primary reinforcing function of visual stimulus reinforcers on FR 5 schedules of reinforcement ( Stewart, 1960) with lights of stronger intens ity maintaining a greater number of responses Furthermore, in the current study not only were sessions conducted during the light cycle but subjects were also fed during the light cycle. Palmatier et al. conducted sessions and fed subjects during the dar k cycle. Rearing conditions (light or dark) have been shown to influence the reinforcing effects of turning on and off houselights ( Roberts, Marx, Collier, 1958). It is important to note, however, that the effects of nicotine were not identical across the two stimulus types, as indicated by the time course analyses i n Figure 3 5. Although nicotine produced a peak in responding in th e second 2 min block for both the Lig hts On and the Lights Off phase the nicotine induced increases in responding diminished t o a greater extent throughout the rem ainder of the Lights On session rel ative to the Lights Off session Palmatier at al. (2007) did not begin experimental sessions until 5 min after the nicotine injection was administered, whereas in Experiment 2 sessions began immediately after nicotine administration. Although not statistically significant, there were slight increases in responding in the group of

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70 rats who turned on the stimulus lights in the Palmatier et al. study. This procedural difference may also ac count for some of the differences between the current study and that of Palmatier et al. (2007) ; however, in Experiment 2 there were still significant increases in responding to turn on the lights when nicotine was delivered, even when the first five minut es were omitted from the analyses. At least two hypotheses have been offered regarding why turning on and turning off visual stimuli might function as primary reinforcers: (1) curiosity, exploration, or novelty and (2) stimulus change (Kish, 1966). If th e visual stimuli used in Experiment 2 maintained responding because of curiosity, exploration, or novelty, then with extended exposure responding maintained by such stimuli should have decreased. Instead responding was sustained over dozens of sessions, an d in some cases even increased over time. Thus, a stimulus change hypothesis is more consistent with the results of Experiment 2, especially because responding during the lights on and lights off phases were comparable. U ltimate explanations regarding wh y a particular consequence serves as a reinforcer are not typically addressed by behavior analysts; however, speculations regarding why visual stimulus change might function as a reinforcer can be made. It is possible that stimulus change in general corres ponds with an increase in access to reinforcement I n the past, rats for which stimulus change functioned as a reinforcer may have been more likely to survive. In other words, the reinforcing effects of visual stimulus change may be due to phylogeny beha vior that occurs because of the natural selection history of the species (Skinner, 1969).

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71 Table 3 1 Proportion of responses on the active lever Lights On Subject Shaping Baseline 1 Nicotine 1 Baseline 2 Nicotine 2 Baseline 3 Vehicle R251 -0.93 + 0.02 0.93 + 0.01 0.93 + 0.02 0.94 + 0.01 0.96 + 0.01 0.98 + 0.01 R252 0.46 + 0.02 0.93 + 0.02 0.88 + 0.02 0.93 + 0.02 0.90 + 0.01 --R253 0.47 + 0.11 0.91 + 0.03 0.98 + 0.01 0.97 + 0.03 0.98 + 0.01 --R254 -0.93 + 0.01 0.97 + 0.01 0.95 + 0.01 0.98 + 0.01 0.97 + 0.01 0.93 + 0.01 R25 5 -1.00 + 0.00 0.98 + 0.01 0.94 + 0.04 0.95 + 0.01 1.00 + 0.00 0.97 + 0.02 R256 0. 60 + 0.0 1 0.94 + 0.02 0.93 + 0.01 0.96 + 0.02 0.95 + 0.02 --R257 0.82 + 0.13 0.77 + 0.05 0.96 + 0.04 0. 85 + 0.0 1 0 7 0 + 0. 12 --R258 -0.92 + 0.02 0.96 + 0.01 0. 90 + 0.03 0.97 + 0.01 0.96 + 0.01 0.94 + 0.02 Lights Off R251 0.38 + 0.11 0.92 + 0.02 0.8 8 + 0.01 ----R252 -0.83 + 0.04 0.90 + 0.02 0.97 + 0.01 0.98 + 0.01 0.97 + 0.01 0.97 + 0.01 R253 -0.91 + 0.01 0.99 + 0.01 1.00 + 0.01 0.99 + 0 .01 0.98 + 0.01 0.99 + 0.01 R254 0.72 + 0.12 0.77 + 0.04 0.92 + 0.01 0.91 + 0.02 0.99 + 0.01 --R255 0.40 + 0.02 0.64 + 0.11 0.96 + 0.01 0.98 + 0.01 0.99 + 0.01 --R256 -0.96 + 0.01 0.98 + 0.01 0.97 + 0.01 0.98 + 0.01 0.97 + 0.01 0.99 + 0.01 R2 57 1.00 + 0.00 1.00 + 0.00 1.00 + 0.00 1.00 + 0.00 1.00 + 0.00 0.99 + 0.01 0.99 + 0.01 R258 0.87 + 0.05 0.81 + 0.05 0.95 + 0.01 0.96 + 0.01 0.97 + 0.02 --

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72 Table 3 2 Proportion of stimulus presentations during which a response was made Lights On Subject Baseline 1 Nico tine 1 Baseline 2 Nicotine 2 Baseline 3 Vehicle R251 0.52 + 0.07 0.45 + 0.06 0.58 + 0.08 0.63 + 0.02 0.66 + 0.07 0.65 + 0.03 R252 0.13 + 0.02 0.37 + 0.04 0.31 + 0.06 0.34 + 0.05 --R253 0.15 + 0.07 0.10 + 0.02 0.20 + 0.04 0.18 + 0.05 -R254 0.23 + 0.08 0.28 + 0.05 0.28 + 0.04 0.30 + 0.02 0.22 + 0.02 0.32 + 0.07 R255 0.13 + 0.10 0.20 + 0.02 0.44 + 0.20 0.28 + 0.02 0.34 + 0.20 0.30 + 0.20 R256 0.41 + 0.10 0.38 + 0.03 0.37 + 0.07 0.47 + 0.09 --R257 0.00 + 0.00 0.00 + 0.00 No stimu li No stimuli --R258 0.34 + 0.10 0.37 + 0.03 0.36 + 0.04 0.34 + 0.04 0.21 + 0.06 0.30 + 0.08 Lights Off R251 0.45 + .05 0.55 + 0.06 ----R252 0.06 + 0.06 0.20 + 0.04 0.38 + 0.07 0.27 + 0.03 0.27 + 0.03 0.29 + 0.04 R253 0.30 + 0.0 9 0.38 + 0.06 0.25 + 0.02 0.29 + 0.03 0.28 + 0.03 0.27 + 0.04 R254 0.28 + 0.10 0.50 + 0.06 0.39 + 0.02 0.33 + 0.03 --R255 No stimuli 0.46 + 0.02 0.46 + 0.01 0.40 + 0.02 --R256 0.20 + 0.04 0.28 + 0.02 0.23 + 0.06 0.41 + 0.01 0.30 + 0.04 0.39 + 0 .05 R257 0.08 + 0.07 0.14 + 0.10 0.13 + 0.10 0.34 + 0.07 0.57 + 0.20 0.18 + 0.10 R258 0.42 + 0.10 0.58 + 0.04 0.35 + 0.05 0.34 + 0.02 --

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73 Table 3 3 Fitted parameter va lues and corresponding r 2 for each linear regression applied to the rate dependent graphs shown in Figure 3 6. Phase Lever Slope y intercept r 2 Lights On Both 68 3 74 0.00 6 Active* 252 5 76 0.0 8 Inactive* 4020 527 0. 11 Lights Off Both 97 559 0.0 07 Active* 486 1 223 0. 12 Inactive 1494 374 0.0 8 Note: Asterisks denote slopes that were significantly different from zero. Lights On : Active F (1,7 8 ) = 6. 42 ; Inactive F (1, 73 ) = 9.02 Lights Off : Active F (1,73) = 10.34 ; Inactive F (1, 6 3 ) = 5.7 6

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74 Figure 3 1.Total Responses during Lights On. Shown are total responses per 60 min for the last five sessions of each condition. The left column shows data from subjects in the Two Lever training group and the right column shows those from the One Lever training group The bottom row shows the mean ( + SEM) for each group. Filled circles represent responding on the active lever and open c ircles represent responding on the inactive lever. Note the different y axes for each subject. Base = baseline, Nic = Nicotine, Veh = Vehicle.

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75 Figure 3 2. Total Responses during Lights Off. Shown are total response s per 60 min for the last five sessions of each condition. The left column shows data from subjects in the Two Lever training group and the right column shows those from the One Lever training group. The bottom row shows the mean ( + SEM) for each group. Fil led circles represent responding on the active lever and open circles represent responding on the inactive lever. Note the different y axes for each subject. Base = baseline, Nic = Nicotine, Veh = Vehicle.

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76 Figure 3 3. Cumulative Response Records during Lights On. Shown is t he last s ession of each condition for two representative subjects from each group (R252 & R258). Deflections in the record indicate stimulus presentations -the pen was reset back to zero at the end of each 10 sec stimulus. Responses after the deflection and above the Baseline Nicotine Baseline Nicotine Two Lever Group R252 Minutes Cumulative Responses Baseline Nicotine Baseline Nicotine Baseline Vehicle One Lever Group R258 Lights On Minutes C umulative Responses

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77 horizontal dotted line but before the pen reset, occurred during the stimulus presentation. Figure 3 4. Cumulative Response Records dur ing Lights Off. Shown is the last session of each condition of the Lights Off phase for two representative subjects from each group (R252 & R258). Deflections in the record indicate stimulus presentations -the pen was reset back to zero at Two Lever Group R252 Cumulative Respon ses Minutes Minutes Two Lever Group R252 Baseline Nicotine Baseline Nicotine Baseline Vehicle Cumulative Responses One Lever Group R258 Lights Off Baseline Nicotine Baseline Nicotine Minutes Cumulative Responses

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78 the end of ea ch 10 sec stimulus. Responses after the deflection and above the horizontal dotted line, but before the pen reset, occurred during the stimulus presentation. Note the higher y axis for the bottom three records of subject R258. Figure 3 5. Within Session Time Course Analyses. Mean + SE M number of responses per 2 min bin during the 60 min session. The left column shows active (top row) and inactive (bottom row) responding during the Lights On phase, while the right column shows responding during the Lig hts Off phase. Each data path within a panel corresponds with a different condition: first baseline (filled circles), first nicotine (open circles), second baseline (filled triangles), second nicotine (open triangles), third baseline (gray stars), vehicle (open stars). Note the different y axes for active and inactive responses. 2 min bin Responses / 2 min bin

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79 Figure 3 6. Rate dependent s catterplots. Rate dependent scatter plots for the Lights On (left column ) and Lights Off (right column) phases of the experiment Shown are the log p ercentages of pre drug response rates plotted as a f unction of log pre drug response rates Response rates on b oth the active (filled circles) and inactive (open circles) levers are shown together on each plot.

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80 CHAPTER 4 G eneral Discussion Mechanisms of Action Behavioral Mechanisms Nicotine as a motivating establishing operation. Thus far, the behavioral mechanism of action implicated by researchers investigating the effects of nicotine on reinforced responding is that it s erves as a motivating establishing operation (MEO). In other words, it serves to enhance the reinforcing value of certain environmental consequences (Chaudhri et al. 2006; Olausson, Jentsch, Taylor, 2004a, b; Palmatier et al, 2007, Xiu et al., 2007; Raiff & Dallery, 2006). With an observing response procedure, Experiment 1 used a group design to show that nicotine increased responding maintained by conditioned reinforcers, but did not cause a general increase in behavior. Experiment 2 demonstrated that tu rning on and turning off a houselight functioned as moderately effective primary reinforcers for rats and that nicotine selectively increased responding maintained by such consequences. The results of Experiments 1 and 2 are consistent with a MEO account o f nicotine induced increases in responding. It is interesting that the MEO effects of nicotine were relatively specific to responding maintained by the conditioned reinforcing visual stimuli in Experiment 1 One might also have expected food maintained res ponding in Experiment 1 to increase (i.e., food extinction responses in the presence of the S+), but no such increases were noted. Although it is possible that the lack of effect was simply due to a ceiling effect, there are a few other possibilities that should be considered. First, it may be the case that nicotine selectively increased moderately reinforcing stimuli, as others have suggested (Palmatier et al., 2007). However, there have been other demonstrations of nicotine increasing responding maintain ed by more potent reinforcers, such as liquid sucrose (Jias & Ellison, 1990), cocaine (Bechtholt & Mark, 2002; McQuown, Belluzi, Leslie, 2007), and alcohol (Clark, Lindgren, Brooks, Watson, Little, 2001; L, Wang, Harding,

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81 Juzytsch, Shaham 2003; Smith, Ho ran, Gaskin, Amit, 1999). In a previous study conducted in our lab, responding maintained by food was increased after chronic nicotine administration (Raiff & Dallery, 2006). There were a number of procedural differences between the current study and the other studies in which nicotine increased responding maintained by more potent primary reinforcers, and thus it is possible that there are specific conditions under which nicotine will serve as a MEO for such consequences. It is also possible that the eff ects of nicotine on the more potent reinforcers listed above were due to a different behavioral or biological mechanism of action At this time however, the MEO role for nicotine provides the most cohesive account with respect to the current data and thos e listed above. One potential disadvantage of adopting the motivating operation account is that it could be used as a hypothetical construct. The term motivating operation is currently used as a summary term, or an intervening variable. In other words, it refers to a group of environmental variables that is related to behavior, but is completely anchored in observable events (MacCorquodale & Meehl, 1948; Mazur, 2005). For instance motivating operations could refer to deprivation procedures, satiation pro cedures, or introduction of some environmental event, like nicotine. All of these manipulations correspond with a concomitant change in behavior (eithe r becoming more or less likely) and are all considered motivating operations. The changes in behavior do not depend in any way on the term mot ivating operation, but instead on the environmental manipulations which the term summarizes. Even if the term were abandoned, the phenomena would continue to exist. The concern is if the term motivating operation drift s from an intervening variable to a hypothetical construct. A hypothetical construct is an actual entity that is thought to exist independent of the observations that led to its identification. These entities are used to explain

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82 the very phenomena that led to their presumed existence ( MacCorquodale & Meehl, 1948 ). In fact, the term motivation has been used to refer to something an individual has or something such t constructs would be dangerous because they could lead to circular explana tions, thereby preventing a more detailed investigation into the environmental determinants of behavior (Skinner, 1953). As long as the term remains an intervening variable, it carries with it a number of advantages. At the most basic level, adopting the term MEO in behavioral pharmacology would make the discipline more conceptually systematic with behavior analysis, from which it has already adopted a number of concepts and procedures (Baer, Wolf, Risley, 1968; Thompson & Schuster, 1968). MEO s have been c reinforcement, and thus the concept could bear great benefits for behavioral pharmacologists as func tion as a reinforcer would be perplexing. Furthermore, adopting the concept of motivating operations could tie together a number of seemingly disparate areas in behavioral pharmacology. Because drugs have been conceptualized as reinforcers, various treatm ent manipulations could be conceptualized in terms of motivating operations. For instance, as described in the General Introduction, nicotine is the primary constituent in tobacco thought to be responsible for smoking maintenance the assumption being th at nicotine serves as a primary reinforcer. Nicotine replacement therapies (NRT), such as the patch or gum, are widely available and are marketed as reducing smoking

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8 3 abstinence induced cravings (Shiffman, Ferguson, Gwaltney, Balabanis, Shadel, 2006;Teneggi Tiffany, Squassante, Milleri, Ziviani, Bye, 2002). Thus, NRT products could be conceptualized as motivating abolishing operations in that they decrease the reinforcing aspects of using tobacco products. Pharmacological agents used to treat other drugs o f abuse are also thought to function in a similar manner, such as methadone maintenance for opioid dependence (Donny, Brasser, Bigelow, Stitzer, Walsh, 2005). In addition to drug abuse treatment, other research areas in behavioral pharmacology that might b e linked by, or benefit from, the notion of motivating operations are self administration ( Haney & Spealman, 2008; Woolverton, Wang, Vasterling, Carroll, Tallarida, 2008) priming (de Wit, 1996; James Walke, Williams, Taylor, & McMillan, 2007), reinstateme nt (Bongiovonni & See, 2008; Liu, Caggiula, Nobuta, Poland, Pechnick, 2006), sensitization to the reinforcing effects of drugs (Liu, Roberts, Morgan, 2005; Ward, Lck, Morgan, Roberts, 2006) and drug interactions (Tanda & Goldberg, 2000; Ward, Lck, Morga n, Roberts, 2006). Specifically related to nicotine, the MEO account has more immediate and obvious benefits in that it can account for extant data on the reinforcer enhancing effects of nicotine and it may lead to novel experiments. For instance, the de finition of a MEO specifies that it leads to an increase in the probability of all responses which have led to the reinforcer in the past. However, the appropriate discriminative stimuli must also be present if the response is to occur, regardless of wh eth er the motivating operation is in place (Michael, 1982). One experiment might consist of training a few different responses that all have the same outcome, but that are trained in the context of a multiple schedule, and thus the different responses occur i n the presence of different discriminative stimuli (e.g., lever press, nose poke, chain pull). If nicotine increases the motivating operation for the consequence in question, then only the response

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84 appropriate to each discriminative stimulus should increas e, whereas the other responses should remain unchanged. Furthermore, t he different response topographies could generate different rates of responding, even within the same organism. These differences in rate of responding would not be expected to affect t he outcomes if nicotine does in fact serve as a MEO Such a procedure might be able to address the rate dependent tendencies of nicotine that were found in Experiments 1 and 2 Other future directions, mentioned earlier, include determining the condition s under which nicotine serves as a MEO for different consequences. Consider the example of food deprivation as a MEO given in the General Introduction. Food deprivation will not increa se the value of all reinforcers; it is specific to food consequences. It may be that nicotine is a MEO for some reinforcers but not others, as the results from Experiment 1 suggested. Most of the research demonstrating the MEO role of nicotine has used visual stimulus reinforcers; therefore, it will be necessary to determine whether responding maintained by reinforcers in other sensory modalities (e.g., auditory, olfactory) are also increased by nicotine administration. Furthermore, it is not clear how nicotine might influence responding maintained or suppressed by different b ehavioral processes, such as negative reinforcement or punishment. Exploring the scope of nicotine as a MEO is an important task if the concept is to have predictive utility. Other behavioral accounts. Before accepting the MEO account for nicotine induce d increases in responding, it is necessary to rule out other behavioral accounts. Two such accounts were addressed in Experiments 1 and 2: (1) general increases in behavior and (2) rate dependence. To investigate whether nicotine caused general increases i n behavior, Experiment 1 showed that responding did not reliably increase during an extinction component, while

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85 Experiment 2 showed that nicotine only increased responding on an active lever, even in subjects who were initially trained to press both the ac tive and inactive levers. The rate dependent analyses from Experiments 1 and 2 indicated that there was a tendency for nicotine to increase low pre drug response rates and to decrease high pre drug response rates. Although there were significant negative slopes, the percentage of variance accounted for was always low, never exceeding 21%, which suggests that the relationship between pre drug and drug response rates is not very well described by a linear function. Thus, the present studies provide d weak ev idence that nicotine has rate dependent effects. Even if the rate dependent effects were more robust, such a finding would only indicate a relationship between two dependent variables (i.e., pre drug response rates and drug response rates), but would not specify a behavioral or biological mechanism of action, such as changes in stimulus control, motoric capabilities, or motivating operations (Branch, 1984; Odum, Lieving, Schaal, 2002). Thus, a rate dependent relationship does not rule out the possibility t hat changes in responding were a function of nicotine serving as a MEO. More work will be necessary to test whether nicotine merely increases low rates of responding, or whether such increases are specific to parameters of the reinforcing stimuli (Lamb & G insburg, 2008). A recent study showed that nicotine also increased the number of completed ratios on a progressive ratio schedule of visual stimulus presentation (Chaudhri et al., 2007), suggesting that nicotine does more than merely increase response rate s. However, future studies should be aimed at teasing apart the importance of response rates on the effects of nicotine administration. Neurobiological Mechanisms In addition to the behavioral mechanisms of action just described, researchers have investig ated corresponding neurobiological mechanisms that might be relevant to the results seen

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86 in Experiments 1 and 2. Although research in this area is extensive, only a brief overview of the findings that seem particularly relevant to the current studies will be addressed. Similar to other drugs of abuse, nicotine administration results in the release of dopamine (DA) in the mesolimbic system, which is comprised of the ventral tegmental area (VTA) and the nucleus accumbens (NAc), among other structures (Wonna cott, Sidhpura, Balfour, 2005). The NAc can be further divided into two distinct sections the core and the shell. Recently, the core and shell have been found to contribute in different ways to drug self administration. Ito, Robbins and Everitt (2004) c ompared the effects of NAc core and shell lesions on cocaine self administration, using a standard self administration procedure and a second order schedule of self administration. Second order schedules are sometimes used to study conditioned reinforcemen t The standard procedure consisted of a FR1 schedule of cocaine infusions paired with a 20 s blackout and i llumination of a stimulus light. T he second order schedule consisted of a FR 10 schedule of stimulus light illumination, such that every 10 th stimul us was paired with a cocaine infusion and 20 s blackout (FR10 [FR10:S]). There were no differences in cocaine self administration in core and shell lesioned rats when the standard procedure was used. However, when the second order schedule was employed, f ewer core lesioned rats met the self administration criterion and those who did meet the criterion made significantly fewer responses than rats in the shell lesioned and control groups. Furthermore, core lesioned and control subjects showed a significant i ncrease in response rates after the first cocaine infusion in the second order schedule, whereas shell The core seems to mediate control by conditioned reinforcers, whereas the shell seems to mediate the potentiation of that control by cocaine, perhaps reflecting stimulant or motivational effects of the ed that the

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87 NAc shell may be related to general increases in behav ior induced by cocaine or to the MEO effects of cocaine on sensory reinforcers. Although they attributed conditioned reinforcing properties to the visual stimuli used in their study, it is not clear whether the stimuli were actually primary reinforcers, as the results from the present Experiment 2 might suggest. Nevertheless, their findings are directly rel ated to the current experiments in that increased DA activity in the NAc core and shell may differentially influence sensory and/ or conditioned reinforce rs. The implications of nicotine induced DA release in the NAc have also been addressed by a number of researchers, and Balfour (2004) recently proposed a theory that directly relates to the MEO mechanism of nicotine outlined above. Balfour was particular ly interested in addressing how nicotine could maintain tobacco use, even if nicotine itself did not function as a primary reinforcer. He suggested that nicotine induced DA release in the NAc core makes it possible for nicotine associated environmental sti muli to become conditioned reinforcers. Furthermore, Balfour suggested that nicotine induced DA release in the NAc shell further potentiates, or serves as a MEO, for those associated stimuli. Thus, Balfour suggested that the NAc core and shell each contrib ute to nicotine self administration, or tobacco use, by establishing and increasing the reinforcing properties of tobacco related stimuli. It might be useful to use the procedures described in Experiments 1 and 2 to further explore this possible neurobiolo gical mechanism of action. Concluding Remarks Given the weak primary reinforcing effects of nicotine, as evidenced by the difficulties in establishing nicotine self administration with nonhumans, the popularity and success of smoking and tobacco use in hu mans is surprising. Thus, we return to the original question : w hat has made tobacco such a successful commodity ? The current findings support a MEO role for nicotine,

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88 which may account for the prevalence of smoking and the difficulty smokers have in quitti ng I f nicotine enhances the reinforcing value of other environmental consequences, then quitting would not only result in a loss of cigarette reinforcers, but also a loss in the value of alternative reinforcers that were enhanced by nicotine.

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89 LIST OF REFERENCES Baer, D. M., Wolf, M. M, & Risley, T. R. (1968). Some current dimensions of applied behavior analysis. Journal of Applied Behavior Analysis, 1 91 97. Balfour, D.J.K. (2004). The neurobiology of tobacco de pendence: A preclinical perspective on the role of the dopamine projections to the nucleus. Nicotine & Tobacco Research, 6 899 912. Baum, W M (1973) The correlation based law of effect. Journ al of the Experimental Analysis of Behavior, 20 137 153. B echtholt, A.J. ,Mark, G.P. (2002). Enhancement of cocaine seeking behavior by repeated nicotine exposure in rats. Psychopharmacology, 162 178 185. Berlyne, D.E. (1957). Uncertainty and conflict: a point of contact between information theory and behavior theory concepts. Psychological Review, 6 4, 329 333. Bongiovanni, M. & See, R.E. (2008). A comparison of the effects of different o perant training experiences and dietary restriction on the reinstatement of cocaine seeking in rats Pharmacology, Biochemis try and Behavior, 89 227 233. Branch, M N (1984) Rate dependency, behavioral mechanisms, and behavioral pharmacology. Journal of the Experimental Analysis of Behavior, 42 511 522. Branch, M. N. (2006). How research in behavioral pharmacology informs behavioral science. Journal of the Experimental Analysis of Behavior 85 407 423. Caggiula, A.R., Donny, E.C., Chaudhri, N., Perkins, K.A., Evans Martin, F.F., Sved, A.F. (2002a). Importance of nonpharmacological factors in nicotine self administration. Physiolological Behavior, 77 683 687. Caggiula, A.R., Donny, E.C., White, A.R., Chaudhri, N., Booth, S., Gharib, M.A., Hoffman, A., Perkins, K.A., & Sved, A.F. (2001). Cue dependency of nicotine self administration and smoking. Pharmacology, Biochemistry and Behavior, 70 515 530. Caggiula, A.R., Donny, E.C., White, A.R., Chaudhri, N., Booth, S., Gharib, M.A., Hoffman, A., Perkins, K.A., & Sved, A.F. (2002b). Environmental stimuli promote acquisition of nicotine self administration in rats. Psychophar macology, 163 230 237. Carlton, PL (1983). A Primer of Behavioral Pharmacology New York: W. H. Freeman & Co. Carmody T.P. (1992). Preventing relapse in the treatment of nicotine addiction: current issues and future directions. Journal of Psychoactive D rugs, 24 131 158.

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90 Case, D.A. & Fantino, E. (1981). The delay reduction hypothesis of conditioned reinforcement and punishment: Observing behavior. Journal of the Experimental Analysis of Behavior, 35, 93 108 Centers for Disease Control and Prevention ( 2005). Annual Smoking Attributable Mortality, Years of Potential Life Lost, and Productivity Losses United States, 1997 2001 Morbidity and Mortality Weekly Report, 54 625 628. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5425a1.htm Centers for Disease Control and Prevention (2006). History of the Surgeon General's Report on Smoking and Health Last updated 2/28/07 Available at: http://www.cdc.gov/tobacco/data_statistics/sgr/history.htm Centers for Disease Control and Prevention (2007). Cigarette Smoking Among Adults United States, 2006 Morbidity and Mort ality Weekly Report, 56 1157 1161 Available from: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5644a2.htm Chaudhri, N., Caggiula, A.R., Donny, E.C., Booth, S. Gharib, S., Craven, R., Al len, S.S., Sved, A.F., Perkins, K.A. (2005). Sex differences in the contribution of nicotine and nonpharmacological stimuli to nicotine self administration in rats. Psychopharmacology, 180 258 266. Chaudhri, N., Caggiula, A.R., Donny, E.C., Booth, S. Gh arib, S., Craven, R., Palmatier, M.I., Liu, X., Sved, A.F. (2006). Operant responding for conditioned and unconditioned reinforcers in rats is differentially enhanced by the primary reinforcement and reinforcement enhancing effects of nicotine. Psychopharm acology, 189 27 36. Chaudhri, N., Caggiula, A.R., Donny, E.C., Booth, S., Gharib, M., Craven, L., Palmatier, M.I., Liu, X., Sved, A.F. (2007). Self administered and noncontingent nicotine enhance reinforced operant responding in rats: Impact of nicotine dose and reinforcement schedule Psychopharmacology 190 353 362. Clark, A Lindgren, S Brooks, S P Watson, W P Little, H J (2001) Chronic infusion of nicotine can increase operant self administration of alcohol. Neuropharmacology 41 108 117. Cohen, C., Perrault, G., Griebel, G., Soubri, P. (2005). Nicotine associated cues maintain nicotine seeking behavior in rats several weeks after nicotine withdrawal: Reversal by the cannabinoid (CB1) receptor antagonist, rimonabant (SR141716). Neuropsy chopharmacology, 30 145 155. Cohen, S.L., Riley, D.S., Weigle, P.A. (1993). Tests of behavioral momentum in simple and Multiple schedules with rats and pigeons. Journal of the Experimental Analysis of Behavior 60, 255 291.

PAGE 91

91 Cooper, M.A. (2004). Tobacc o industry: do ads and new products still target teen smokers? CQ Researcher, 14 1025 1049. Cooper, J.O., Heron, T.E., Heward, W.L. (2007). Applied Behavior Analysis. Upper Saddle River, NJ: Pearson Education, Inc. Corrigall, W.A. & Coen, K.M. (1989). N icotine maintains robust self administration in rats on a limited access schedule. Psychopharmacology, 99 473 478. Dallery, J., Houtsmuller, E. J., Pickworth, W. B., & Stitzer, M. (2003). Effects of cigarette nicotine content and smoking pace on subseque nt craving and smoking. Psychopharmacology, 165, 172 180. Dar, R. & Frenk, H. (2002a). Nicotine addiction: fact or theory? Addiction Research and Theory, 10 219 224. Dar, R. & Frenk, H. (2002b). Nicotine self administration in animals: a reevaluation. Addiction Research and Theory, 10 545 579. Dar, R. & Frenk, H. (2004). Smokers do not self administer nicotine other than in tobacco: a reply to Perkins (2004). Psychopharmacology, 175 259 261. Dar, R. & Frenk, H. (2005). Nicotine may reinforce intra venous drug taking in drug users: a comment on Harvey et al.. Psychopharmacology, 179 516 517. Davison, M & Baum, W M (2007) Do conditional reinforcers count? Journal of the Experimental Analysis of Behavior, 86, 269 283. Denoble, V.J. & Mele, P.C. ( 2006). Intravenous nicotine self administration in rats: effects of mecamylamine, hexamethonium and naloxone. Psychopharmacology (Berl), 184 266 72. de Wit, H. (1996). Priming effects with drugs and other reinforcers. Experimental and Clinical Psychopha rmacology, 4 5 10. Dews, P. B. (1955). Studies on behavior. I. Differential sensitivity to pentobarbital of pecking performance in pigeons depending on schedule of reward. Journal of Pharmacology of Experimental. Therapeutics, 113 393 401. Dicesare, A .. McAdam, D.B Toner, A., Varrell, J. (2005). The effects of methylphenidate on a functional analysis of disruptive behavior: A replication and extension. Journal of Applied Behavior Analysis, 38 125 128. Dinsmoor, J.A. (1983). Observing and conditione d reinforcement. Behavioral and Brain Sciences, 6 693 728.

PAGE 92

92 Dinsmoor, J.A., Brown, M.P., Lawrence, C.E. (1972). A test of the negative discriminative stimulus as a reinforcer of observing. Journal of the Experimental Analysis of Behavior, 18, 79 85 Dol s, M., Willems, B., & van den Hout, M. (2000). Smokers can learn to influence their urge to smoke. Addictive Behaviors, 25, 103 108. Donny, E.C., Brasser, S.M., Bigelow, G.E., Stitzer, M.L., Walsh, S.L. (2005). Methadone doses of 100 mg or greater are mor e effective than lower doses at suppressing heroin self administration in opioid dependent volunteers. Addiction, 100 1496 1509. Donny, E.C, Chaudhri, N., Caggiula, A.R., Evans Martin, F.F., Booth, S., Gharib, S., Clements, L.A., Sved, A.F. (2003). Opera nt responding for a visual reinforcer in rats is enhanced by noncontingent nicotine: implications for nicotine self administration and reinforcement. Psychopharmacology, 169 68 76. Dwoskin, L.P., Crooks, P.A., Teng, L., Green, T.A., Bardo, M.T. (1999). A cute and chronic effects of nornicotine on locomotor activity in rats: altered response to nicotine. Psychopharmacology, 145 442 451. Fantino, E. (1977). Conditioned reinforcement: Choice and information. In Honig, W.K. & Staddon, J.E.R. (eds) Handbook o f Operant Behavior ( pp 313 337) Englewood Cliffs, N.J.: Prentice Hall. Faraday, M.M, Elliott, B.M, Phillips, J.M., Grunberg, N.E. (2003). Adolescent and adult Pharmacology, Biochemistry, and B ehavior, 74, 917 931. Federal Trade Commission (2005). Federal Trade Commission Issues Cigarette Report for 2003: Marketing Expenditures Increased to $15.15 Billion, the Most Ever Reported to the FTC Online source: http://www.ftc.gov/opa/2005/08/cigreport.htm Field, M., & Duka, T. (2001). Smoking expectancy mediates the conditioned responses to arbitrary smoking cues. Behavioural Pharmacology, 12, 183 194. Fleshler, N & Hoffman, H (1962). A progression for generating variable interval schedules. Journal of the Experimental Analysis of Behavior 5, 529 530. Food and Agricultural Organization (2003). Projections of tobacco production, consumption and trade by 2010 Rome. Frenk, H. & Dar, R. ( 2000). A critique of nicotine addiction New York, NY: Plenum Publishers. Frenk, H & Dar, R (2004). Reward potentiation or behavioral activation? A commen t on Donny et al. Psychopharmacology 171 472 473

PAGE 93

93 Gold, M. (1995). Tobacco. Drugs of Abuse: a com prehensive series for clinicians, 4 1 211. Goldberg, S.R., Spealman, R.D., Goldberg, D.M. (1981). Persistent behavior at high rates maintained by intravenous self administration of nicotine. Science, 214 573 575. Goodrick, C. (1970). Light and dark co ntingent bar pressing in the rat as a function of age and motivation. Jou rnal of Comparative and Physiol ogical Psychology, 73 100 104. Green, T.A., Cain, M.E., Thompson, M., Bardo, M.T. (2003). Environmental enrichment decreases nicotine induced hyperac tivity in rats. Psychopharmacology, 170 235 241. Griffiths, R.R., Wurster, R.M., Brady, J.V. (1981). Choice between food and heroin: effects of morphine, nalaxone, and secobarbitol. Journal of the Experimental Analysis of Behavior, 35 335 351. Haney, M & Spealman, R. (2008). Controversies in translational research: drug self administration. Psychopharmacology online first. Harris, A.C., Burroughs, D., Pentel, P.R., LeSage, M.G. (2008 ). Compensatory nicotine self administration in rats during reduce d access to nicotine: an animal model of smoking reduction. Experimental and Clinical Psychopharmacology, 16 86 97. engravings in the library of George Arents, Jr. by Jerome E. Brooks. William and Mary College Quarterly Historical Magazine, 22 101 113. Hendry, D.P. (1969). Introduction. In Hendry (ed) Conditioned Reinforcemen t. (pp1 33). Homewood, I l : The Dorsey Press. Henningfield, J.E. & Zeller, M. (2006). Ni cotine psychopharmacology research contributions to United States and global tobacco regulation: a look back and a look forward. Psychopharmacology, 184, 286 291. Huynh, H & Feldt, L S (1976). Estimation of the Box correction for degrees of freedom fro m sample data in randomized block and split plot designs. Journal of Educational Statatistics, 1 69 82. Ito, R., Robbins, T.W., Everitt, B.J. (2004). Differential control over cocaine seeking behavior by nucleus accumbens core and shell. Nature Neurosci ence, 7 389 397. Iwata, B. A., Dorsey, M. F., Slifer, K. J., Bauman, K. E., & Richman, G. S. (1994). Toward a functional analysis of self injury. Journal of Applied Behavior Analysis, 27 197 209.

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94 Iwata, B. A., Smith, R. G., & Michael, J. L. (2000). C urrent research on the influence of establishing operations on behavior in applied settings. Journal of Applied Behavior Analysis, 33 411 418. James Walke NL, Williams HL, Taylor DA, McMillen BA. (2007). Periadolescent nicotine exposure produces sensitiz ation to reinforcement by diazepam in the rat. Neurotoxicology and Teratology, 29 31 36. Jias, L M & Ellison, G (1990) Chronic nicotine induces a specific appetite for sucrose in rats. Pharmacology, Biochemist r y, and Behavior, 35 489 491. Jwaideh A.R. & Mulvaney, D.E. (1976). Punishment of obs erving by a stimulus associated with the lower of two reinforcement frequencies. Learning and Motivation, 7, 211 222. Kelleher, E. & Gollub, L.R. (1962). A review of positive conditioned reinforcement. Jou rnal of the Experimental Analysis of Behavior, 5 543 597. Kendall, S. B. (1973). Redundant information in an observing response procedure. Journal of the Experimental Analysis of Behavior, 19 81 92. Killeen, P.R., Hanson, S.J., Osborne, S.R. (1978). Arousal: genesis and manifestation as response rate. Psychological Review, 85 571 581. Kluger, R. (1997). year cigarette war, the public health, and The unabashed triumph of Philip Morris. New York: Alfred A. Knopf, Inc Koehl, M., Bjijou, Y., Le Moal, M., Cador, M. (2000). Nicotine induced locomotor activity is increased by preexposure of rats to prenatal stress. Brain Research, 882 196 200. Kosowski, A.R., Liljequist, S. (2005). Behavioural sensitization to nicotin e precedes the onset of nicotine conditioned locomotor stimulation. Behavior and Brain Research, 156, 11 17. Lamb, R.J & Ginsburg, B.C. (2008). Reinforcement magnitude modulates the rate dependent effects of fluvoxamine and desipramine on fixed interval responding in the pigeon. Behavioural Pharmacology, 19 51 60. Laraway, S, Snycerski, S, Michael, J, Poling, A (2003). Motivating operations and terms to describe them: some further refinements. Journal of the Experimental Analysis of Behavior 36 4 07 414. L, A D Wang, A Harding, S Juzytsch W Shaham, Y (2003) Nicotine increases alcohol s elf administration and reinstates alcohol seeking in rats. Psychopharmacology, 168, 216 221.

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95 Le Foll, R., Wertheim, C., Goldberg, S.A (2007) High r ei nforc ing efficacy of nicotine in non h uman p rimates. Public Library of Science, 2 1 9. Lile, J.A., Nader M.A. (2003). The abuse liability and therapeutic potential of drugs evaluated for cocaine addiction as predicted by animal models. Current Neuropha rmacology 1 21 46 Liu, X., Caggiula, A.R., Yee, S.K., Nobuta, H., Poland, R.E., Pechnick, R.N. (2006). Reinstatement of nicotine seeking behavior by drug associated stimuli after extinction in rats. Psychopharmacology, 184 417 425. L iu X., Palmatier M I Caggiula, A R Donny, E C Sved, A F (2007). Reinforcement enhancing effect of nicotine and its attenuation by nicotinic antagonists in rats. Psychopharmacology, 194 463 473. Liu, Y., Roberts, D.C.S., Morgan, D. (2005). Sensitization of the re inforcing effects of self administered cocaine in rats: effects of dose and intravenous injection speed. European Journal of Neuroscience, 22 195 200. Lubow, R.E. & Moore, A.U. (1959). Latent inhibition: the effect of nonreinforced pre exposure to the c onditional stimulus. Journal of Comparative and Physiological Psychology, 52 415 419. Lucki, I. (1983) Rate dependent effects of amphetamine on responding under random interval schedules of reinforcement in the rat. Pharmacology, Biochemistry, and Behav ior, 18 195 201. MacCorquodale, K. & Meehl, P.E. (1948). On a distinction betw een hypothetical constructs and intervening variables. Psychological Review, 55 95 107. Marx, M.H., Henderson, R.L., & Roberts, C.L. (1955). Po sitive reinforcement of the ba r pressing response by a light stimulus following dark operant pretests with no afteraffect. Journal of Comparative and Physiological Psycholog y, 48, 73 76. Mazur, J.E. (2005). Learning and Behavior 6/E. Upper Saddle River, NJ: Prentice Hall McAdam, D.B Klatt, K.P., Koffarnus, M., Dicesare, A., Solberg,K. Welch, C.,Murphy, S. (2005). The effects of establishing operations on preferences for tangible items. Journal of Applied Behavior Analysis, 38 107 110. McComas, J., Hoch, H., Paone, D., & El Roy D. (2000). Escape behavior during academic tasks: A preliminary analysis of idiosyncratic establishing operations. Journal of Applied Behavior Analysis, 33 479 493. McQuown, S C Belluzi, J D Leslie, F M (2007) Low dose nicotine treatment during e arly adolescence increases subsequent cocaine reward. Neurotoxicology and Teratology, 29 66 73.

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96 McKim, W.A. (1997). Drugs and behavior: an introduction to behavioral pharmacology (3 rd ) Upper Saddle River, NJ: Prentice Hall, Inc. Michael, J. ( 1982 ) D istinguishing between discriminative and motivational functions of stimuli. Journal Experimental Analysis of Behavior, 37 149 155. Michael, J. (1993). Establishing operations. The Behavi o r Analyst 16 191 206. Michael, J., (2000). Implications and refi nements of the establishing operation concept. Journal of Applied Behavior Analysis, 33, 401 410. Negus, S.S. (2006). Choice between heroin and food in nondependent and heroin dependent rhesus monkeys: effects of naloxone, buprenorphine, and methadone. J ournal of Pharmacology and Experimental Therapeutics, 317 711 723. Nevin, J A (1974) Response strength in multiple schedules. Journal Experimental Analysis of Behavior 21 389 408. Nevin, J A & Grace, R C (2000). Behavioral momentum and the Law of E ffect. Behavior and Brain Sciences, 23 73 130. Northup, J., Fusilier, I., Swanson, V., Roane, H., & Borrero, J. (1997) An evaluation of methylphenidate as a potential establishing operation for some common classroom reinforcers. Journal of Applied Behav ior Analysis, 30 615 625. hour access to intravenous nicotine self administration. Pharmacology, Biochemistry, and Behavior, 86, 346 353. Odum, A.L., Lieving, L. M., Schaal, D.W. (2002). Effects of d amphetamine in a temporal discrimination procedure: s elective changes in timing or rate dependency? Journal Experimental Analysis of Behavior 78 195 214. Olausson, P., Jentsch, J.D., Taylor, J.R. (2004a). Nicotine e nhances responding with conditioned reinforcement. Psychopharmacology, 171 173 178. Olausson, P., Jentsch, J.D., Taylor, J.R. (2004b). Repeated nicotine exposure enhances responding with conditioned reinforcement. Psychopharmacology, 17, 98 104. Palmati er, M.I., Evans Martin, F.F., Hoffman, A., Caggiula, A.R, Chaudhri, N, Donny, E.C, Liu, X., Booth, S. Gharib, S., Craven, R., Sved, A.F. (2006). Dissociating the primary reinforcing and reinforcement enhancing effects of nicotine using a rat self administ ration paradigm with concurrently available drug and environmental reinforcers. Psychopharmacology, 184 391 400.

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97 Palmatier, M.I, Matteson, G.L., Black, J.J., Liu, X., Caggiula, A.R., Craven, L., Donny, E.C., Sved., A.F. (2007). The reinforcement enh ancing effects of nicotine depend on the incentive value of non drug reinforcers and increase with repeated drug injections. Drug and Alcohol Dependence, 89 52 59. Panagis, G., Nisell, M., Nomikos, G.G., Chergui, K., Svensson, T.H. (1996). Nicotine injec tions into the ventral tegmental area increase locomotion and Fos like immunoreactivity in the nucleus accumbens of the rat Brain Research, 730 133 142. Patall, E.A., Cooper, H., Robinson, J.C. (2008). The effects of choice on intrinsic motivation and related outcomes: a meta analysis of research findings. Psychological Bulletin, 134 270 300. Perkins, K A (1999) Baseline dependency of nicotine effects: a review. Behavioural Pharmacolology, 10 597 615 Pickens, R. & Thompson, T. (1968). Cocaine re inforced behavior in rats: effects of reinforcement magnitude and fixed ratio size. The Journal of Pharmacology and Experimental Therapeutics, 161 122 129. Pierce, C.P. & Kumaresan, V. (2006). The mesolimbic dopamine system: The final common pathway fo r the reinforcing effect of drugs of abuse? Neuroscience and Biobehavioral Reviews, 30 215 238. Pierce, J.P., Choi, W.S., Gilpin, E.A., Farkas, A.J., Berry, C.C. (1998). Tobacco industry promotion of cigarettes and adolescent smoking. Journal of the Ame rican Medical Association, 279 511 516. Poling, A. & Byrne, T. (2000). Introduction to behavioral pharmacology Reno, NV: Context Press. Raiff, B.R. & Dallery, J. (2006). Effects of acute and chronic nicotine on responses maintained by primary and con ditioned reinforcers in rats Experimental and Clinical Psychopharmarmacology, 14 296 305. Roberts C.L., Marx, M.H., & Collier, G. (1958). Light onset and light offset as reinforcers for the albino rat. Journal of Comparative and Physiological Psychology 51, 575 579. Robinson, J.S. (1959). Light onset and termination as re inforcers for rats living under normal light conditions. Psycholological Reports, 5 793 796. Rose, J. E., Behm, F. M., Westman, E. C., & Johnson, M. (2000). Dissociating nicotine and nonnicotine components of cigarette smoking. Pharmacology Biochemistry and Behavior, 67, 71 81.

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98 Rose, J. E., Tashkin, D. P., Ertle, A., Zinser, M. D., & Lafter, R. (1985). Sensory blockade of smoking satisfaction. Pharmacology Biochemistry and Behavi or, 23, 289 293. Russell, M.A.H. (1971). Cigarette smoking: natural history of dependence disorder. British Journal of Medical Psychology, 44 1 16. Saulsgiver, K.A., McClure, E.A., Wynne, C.D.L. (2007). Effects of amphetamine on differential reinforcem ent of low rates of responding. Behavioural Pharmacolacology, 18 119 133 Schuster, R. H. (1969). A functional analysis of conditioned reinforcement. In Hendry, DP (ed), Conditioned reinforcement The Dorsey Press, Homewood, IL, pp 192 235. Segal, E. (1959). Confirmation of a positive relation between deprivation and number of responses emitted for light reinforcement. Journal of the Experimental Analysis of Behavior, 2 165 169. Shaefer, G.J. & Michael, R.P. (1986). Task specific effects of nicotine in rats: intracranial self stimulation and locomotor activity. Neuropharmacology, 25 125 131. Shahan, T.A. (2002). Observing responses: effects of rate and magnitude of primary reinforcement. Journal of the Experimental Analysis of Behavior, 78 161 178 administration more resistant to price increases. Psychopharmacology, 167, 180 186. Shahan, T.A. & Podlesnik, C.A. (2005). Rate of conditioned reinforcement affects o bserving rate but not resistance to change. Journal of the Experimental Analysis of Behavior 84 1 17. Shiffman, S., Ferguson, S.G., Gwaltney, C.J., Balabanis, M.H., Shadel, W.G. (2006). Reduction of abstinence induced withdrawal and craving using high d ose nicotine replacement therapy. Psychopharmacology, 184 637 644. Sizemore, O. J., & Lattal, K. A. (1977). Dependency, temporal contiguity, and response independent reinforcement. Journal of the Experimental Analysis of Behavior, 27 119 125. Skinner, B. F. (1953). Science and human behavior. New York: Macmillian. Smith, BR, Horan, JT, Gaskin, S, Amit, Z (1999). Exposure to nicotine enhances acquisition of ethanol drinking by laboratory rats in a limited access paradigm. Psychopharmacology 142 408 4 12. Stewart, G.G. (1967). A history of the medicinal use of tobacco 1492 1860. Medical History, 11 228 268. Stewart, J. (1960). Reinforcing effects of light as a function of intensity and reinforcement schedule. Journal of Comparative and Physiological P sychology, 53 187 193.

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99 Stitzer, M., Morrison, J., Domino, E.F. (1970). Effects of nicotine on fixed interval behavior and their modification by cholinergic antagonists. J ournal of Pharmacol ogy and Exp erimental Ther apeutics, 171 166 177 Stolerman, I.P. (1999). Inter species consistency in the behavioural pharmacology of nicotine dependence Behavioural Pharmacology, 10 559 580. Stolerman I, Jarvis M.(1995). The scientific case that nicotine i s addictive. Psychopharmacology (Berlin), 117 2 10. Strau b, D.M., Hills, N.K., Thompson, P.J., Moscicki, A. (2003). Effects of pro and anti tobacco Journal of Adolescent Health, 32 36 43. Tanda, G. & Goldberg, S.R. (2000). Alteration of the behaviora l effects of nicotine by chronic caffeine exposure. Pharmacology, Biochemistry, and Behavior, 66 47 64. Tapp, J.T., Mathwson, D.M., & Simpson, L.L. (1968). Effects of hunger and thirst on reinforcing properties of light onset and light offset. Journal o f Comparati ve and Physiological Psychology 66 784 787. Teneggi, V., Tiffany, S.T., Squassante, L., Milleri, S., Ziviani, L., Bye, A. ( 2002 ). Smokers deprived of cigarettes for 72 h: effects of nicotine patches on craving and withdrawal. Psychopharmacology, 164 177 187. Thompson, T. (2007). Relations among functional systems in behavior analysis. Journal of the Experimental Analysis of Behavior 87 423 440. Thompson, T. & Schuster, C.R. (1964). Morphine self administration, food reinforced and avoidance behaviors in Rhesus monkeys. Psychopharmacologia, 5 87 94 Thompson, T. & Schuster, C.R. (1968). Behavioral pharmacology Englewood Cliffs, NJ: Prentice Hall, Inc. Vale, A.L. & Balfour, D.J.K. (1989). Aversive environmental stimuli as a factor in the ps ychostimulant response to nicotine. Pharmacology, Biochemistry and Behavior, 32 857 860. Valentine, J.D., Hokanson, Matta, S.G., Sharp., B.M. (1997). Self administration in rats allowed unlimited access to nicotine. Psychopharmacology, 133 300 304. Wa rd, S.J., Lck, C. Morgan, D., Roberts, D.C.S. (2006). Discrete trials heroin self administration produces sensitization to the reinforcing effects of cocaine in rats. Psychopharmacology, 185 150 159.

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100 Wenger, G.R. & Dews, P.B. (1976). The effects of ph encyclidine, ketamine, d amphetamine and pentobarbital on schedule controlled behavior in the mouse. Journal of Pharmacology and Experimental Therapeutics, 196 616 624. Westman, E. C., Behm, F. M., & Rose, J. E. (1996). Dissociating the nicotine and airw ay sensory effects of smoking. Pharmacology Biochemistry and Behavior, 53, 309 315. Williams, B.A. (1994). Conditioned reinforcement: Experimental and theoretical issues. The Behavior Analyst, 17, 261 285. Woods, J.H. & Winger, G.D. (2002). Observing r esponses maintained by stimuli associated wi th cocaine or remifentanil reinforcement in rhesus monkeys. Psychopharmacology, 163 345 351. Woolverton WL, Wang Z, Vasterling T, Carroll FI, Tallarida R. (2008). Self administration of drug mixtures by monkeys : combining drugs with comparable mechanisms of action. Psychopharmacology, 196 575 582. Wonnacott, S., Sidhpura, N., Balfour, D.J.K. (2005). Nicotine: From molecular mechanisms to behavior. Current Opinion in Pharmacology, 5 53 59. Wyckoff, L. B. (1 952). The role of observing responses in discrimination learning. Psychological Review, 59, 431 442.

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101 BIOGRAPHICAL SKETCH My first experiences with behavior analysis and radical behaviorism were with Dr. Gregory Madden at the University of Wisconsin Eau Claire. While I was in Eau Claire I took several behavior analysis courses (e.g., Learning, Applied Behavior Analysis, Advanced Experimental Analysis of Behavior) and I had the chance to work as a teaching assistant for an introductory course in behavior analysis. Dr. Madden and I collaborated on two areas of research: (1) studying potential differences in human responding on a delay discounting task when the consequences were real versus hypothetical, and (2) investigating whether human behavior was bette r described by the matching law when responses were maintained by concurrent schedules of negative reinforcement versus concurrent schedules of positive reinforcement. The former project resulted in two publications and the latter project served as my unde rgraduate thesis. Both projects were presented at the annual conferences for the Association for Behavior Analysis and the Midwestern Association for Behavior Analysis, providing me with opportunities to talk to and get feedback from important figures in t he field. As an undergraduate I was introduced to the subdiscipline of behavioral pharmacology, which was particularly important to me because I was always interested in drug use and abuse. Specifically, Dr. Madden talked about a behavioral treatment for drug abuse known as Dallery in the Behavior Analysis program at University of Florida, was conducting research on contingency management with smokers, in addition to studying issues that were consistent with the topics I studied as an undergraduate ( e.g., matching law, delay discounting). Not only were University of Flor ida also consisted of several other faculty members with broad interests.

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102 While a student at the University of Florida, I have had extensive professional, research, and academic development experiences. I first author ed three manuscripts and co author ed a number of others I wrote two grants submitted to the National Institue of Health (an R03 and NRSA). I was co investigator on the R03 grant which supported the animal research discussed in this manuscript. In addition to writing, I served as a Graduate In structor for two semesters, where I was able to design a course in Applied Behavior Analysis. I conducted numerous research exp eriments with Dr. Dallery, ranging from the basic non human animal studies described in my dissertation, as well as human laborat ory and outpatient research with smokers. In addition to the research I conducted with Dr. Dallery, I also had the opportunity to collaborate on a couple of research projects wit h Dr. Timothy Hackenberg, studying token loss as a form of response cost puni shment with pigeons Collectively, my undergraduate and graduate school experiences solidified my enthusiasm about pursuing a career that allows me to teach the principles and theoretical foundations of behavior analysis and behavioral pharmacology. I am interested in working in an academic setting that includes a balance between teaching and research.