Amygdaloid and cortical lesions in rats

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Title:
Amygdaloid and cortical lesions in rats effect on response to incentive change and on the latent extinction phenomenon
Physical Description:
vi, 69 leaves. : illus. ; 28 cm.
Language:
English
Creator:
Thomas, Wilbur Alan, 1929-
Publication Date:

Subjects

Subjects / Keywords:
Rats   ( lcsh )
Animal behavior   ( lcsh )
Psychology thesis Ph. D   ( lcsh )
Dissertations, Academic -- Psychology -- UF   ( lcsh )

Notes

Thesis:
Thesis--University of Florida, 1966.
Bibliography:
Bibliography: leaves 65-68.
General Note:
Manuscript copy.
General Note:
Vita.

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Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 000559263
oclc - 13452615
notis - ACY4712
System ID:
AA00002237:00001

Full Text










AMYGDALOID


AND


CORTICAL


LESIONS


RATS


EFFECT


ON


RESPONSE


TO


INCENTIVE


CHANGE


AND


ON


THE


LATENT


EXTINCTION


PHENOMENON


WILBUR ALAN THOMAS








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















ACKNOWLEDGMENTS


The author wishes


express


his gratitude


to the members of his


committee,


Prof.


Bradford N


Bunnell,


Chairman,


Prof.


Wilse


Webb,


Prof.


Richard J.


Anderson,


Prof.


Henry


S. Pennypacker,


Prof.


V. D. Saunders.


He is especially appreciative of the


sustained


interest and helpful direction provided by his chairman in


completing


this


research project.


Invaluable assistance in the form of constructive


criticism and procedural mechanics from Mr.


Earl Burkett


also


gratefully acknowledged.
















TABLE OF CONTENTS


Page


ACKNOWLEDGMENTS. . . . . . .


LIST OF FIGURES . . . . . . . .

LIST OF TABLES ....... ......................


CHAPTER


I. INTRODUCTION .............

II. IM ETHOD . . . . . .





IV. DISCUSSIONJJ0A . .. . .. .. .. . .. *


V. S UMMAR0Y ... lV.. ... ... ... .


APPENDICES


REFERENCES ........


BIOGRAPHICAL SKETCH


............. .. ........ 65















LIST OF FIGURES


Figure

1. Means of Reciprocals of Starting Latency in a Straight
Alley with Shift to Small Incentive . . .


Page


Means of Reciprocals of Starting Latency in a Straight


Alley with Shift to Large Incentive.


Means of Reciprocals of Running Time in a Straight


Alley with Shift to Small Incentive


Means of Reciprocals of Running Time in a Straight
Alley with Shift to Large Incentive . . . .

Means of Reciprocals of Latency Trials (A and B) and


Running Time (C and D) for 1st Post-Shift


Sess


Emotionality Scores for Pre-Operative and 1st and 2nd


Post-Operative Ratings


ion
















LIST OF TABLES


Table


Page


Analysis


of Variance of Latency for


Last Pre-Shift


Session
Session


with
with


945 mg.
90 mg.


Reward and 1st P


ost-Shift


Reward


Anal


ysis


of Variance


of Latency for


t Pre-Shift


Session with
Session with


90 mg.
945 mg.


Reward and 1st Pos
Reward . .


t-Shift


Analysis
Pre-Shift


of Variance of Running


Session with


945 mg.


Spee


d for


Last


Reward and 1st Post


Shift


Session


with


90 mg.


Reward.


Analysis
Pre-Shift


of Variance of Running


Session with


90 mg.


Spee


d for


Last


Reward and 1st Post-


Shift


Session


with


945 mg.


Reward.


Analysis
Speed for


of Variance


of Difference


6th and 1st Post-Shift


cores


Sessions with


of Running


90 mg.


Reward


Analysis
Speed for
Reward .


of Variance


6th and 1


of Difference


st Post-Shift


core


Sessions


of Runnin


with


945 mg.


Analysis of Variance


of Latency for


6th and 1st Post


Shift


Sessions


with


945 mg.


Reward


Random Groups Analysis
Last Pre-Shift Session.


Random Groups


Speed for


of Variance of Latency for
. . S S . S .


Analysis of Variance of Running


Last Pre-Shift Session










Table

11.


Page


Mean Number of Correct Responses


Occurring on


T Maze in Acquisition and under
Latent Extinction Conditions. .


Analysis


Normal and


of Variance of Difference in Emotionality


Scores


between P


re-


Operative and 1st Po


Operative


Ratings.


*. . * 0 30


Analysis


of Variance of Difference in Emotionality


Scores


between Pr


e-Ope


rative and 2nd Post-


Operative


Rating s


a 0. .. .. . .S. 0 3 0


Means of Re


Pre -Shift


ciprocals
ssion with


of Starting


90 m


Latency for


Last


Reward and 1st


and 6th Post


-Shift


Sessions


with


945 mg.


Reward


. . 58


Means of Re


Pre -Shift


ciprocals
ssion with


of Starting Latency for


945 mg.


Last


Reward and 1st


and 6th Post


-Shift


Sessions


with


90 mg.


Reward


S59


Means of Running Speed for


Last Pre-Shift


Session


with


90 mg.


Reward and 1st and 6th Post-Shift


Sessions


with


945 mg.


Reward


S* .. 60


Means


of Running Speed for


Last Pre-Shift


sion


with


945 mg.


Reward and 1st and


6th Post


-Shift


Sessions


with


90 mg.


Reward


Reciprocals of Running Time by


Trials


for 1st P


ost-


Shift


Session


S. . 62


Mean Emotionality


Two


Scores


Post-Operative Ratings .


for Pre-Operative Rating


. .5 . 0 63


Rank Order of Posterior


Extent of Amygdaloid


Lesions


and Anterior-Posterior


Extent in Micra















CHAPTER I

INTRODUCTION


This


study consisted of an investigation of the effect of lesions in


the amygdaloid complex and in the


lateral neocortex of laboratory rats


on (1) changes in starting latency and running speed

as a function of change in magnitude of food reward,


in a straight alley


acquisition and


latent extinction in a


maze,


(3) change in threshold of reactivity or


emotionality


as determined by the King emotionality


scale,


(4) the


quantity of food consumed over two consecutive days.


research had as its major aim the elucidation of a syndrome


produced in monkeys


by temporal lobectomy and described some years


ago by


Kluver and Bucy (1939).


Included in the


syndrome were changes


in dietary


behavior and changes in fear reactions and/or


emotionality.


Dietary anomalies took the form of indiscriminate feeding and a general


failure


to consider the palatibility of objects,


while


the emotionality


change tended


to be in the direction of placidity and failure to avoid dan-


,erous


situations or noxious


stimuli.


A large number of studies have


since indicated that most of the


symptoms originally described by










Secondly,


the study had as a goal some


clarification of the role of


the amygdala as a structure within the


limbic


system,


a system which


has been viewed


as playing a major role in insuring the continuity and


sequencing of behavior


(Pribram,


1960).


This


theoretical point of view,


based in large part on observations of behavioral disruptions following


lesions within the limbic


system,


provides a means of describing in


broader perspective a number of seemingly unrelated behavioral


changes


produced by


such lesions.


Thus,


the disturbance of hoarding and mater-


nal behaviors


observed in rats following


cingulate lesions


(Stamm,


1954;


Stamm,


1955) could be described


as reflecting the animal'


inability to


perform the


component parts of a complex pattern of behavior in proper


sequence.


The disturbance of nest building activities


in rats


produced


by cingulate


lesions


(Kim,


1960) might also point to the disruption of


some


sequencing mechanism.


The reported observations of hyperphagia


in amygdalectomized animals


(Pribram and Bagshaw,


Green,


Clemente


, and de Groot,


1957) is


depicted


as again reflecting a failure


of sequencing--thus,


"Feeding


behavior may be difficult to initiate;


once


it has


started it is difficult to stop"


(Pribram,


1960).


sequencing


concept,


then,


is generalized to include the initiation and termination of


behavior at appropriate times.

Additional support for this theory comes through data taken from










seemed to produce deficits in the patients'


ability to carry out a pro-


longed digit span task in the


presence of distracting


stimuli and seemed


to also negatively affect the persons'


memory of how to get from one


place to another--i. e. ,


from the grocery store to his


home.


With these


patients


there appeared,


however,


to be no global loss


of memory for


events


occurring prior to surgery.


Such


was


not the case with a patient


described by

ral lobes rer


Terzian and Ore (1955).


noved,


The patient,


including most of the uncus


who had both tempo-


and hippocampus,


not recognize


his parents after the operations.


Thus,


the clinical data


suggests


that when the damage involves the


hippocampus,


there


is a sub-


stantial loss


of memory.


An alternative interpretation.


Current speculation concerning the


role of the


limbic


system in behavior


also developed along another


theoretical line--i.


it is


central in the mediation of emotional expres-


sion and in the maintenance of adequate


levels of motivation.


Although


the results of the majority of relevant studies

observations of Kluver and Bucy that removal


have concurred with the

of the amygdala produces


a marked lack of emotional


responsiveness


(Pribram and Bagshaw,


1953;


Weiskrantz,


1956; King and Meyer,


1958),


there have been some excep-


tions.


Bard and Mountcastle


(1948)


reported an increase in aggressive-


ness


of three amygdalectomized cats.


Two of the three,


however,


sus-










found that amygdalectomized monkeys


responded aggressively toward


their


handlers,


but less


aggressively toward other monkeys.


Schreiner


and Kling


(1953) produced several amygdalectomized cats with a low


rage threshold using the same techniques which produced placidity in a


number of others.


Hence,


the effect of amygdalectomy on emotionality


does not seem to be entirely predictable.


In some


cases


where amygdalectomy has produced increased emo-


tionality a focal discharge to the hippocampus may be


responsible.


Green (1964)


indicated that the hippocampus


a low seizure thres-


hold in man and in animals and that injuries to Ammon' s


horn


as well


as electrical stimulation of this area can give rise to seizure discharges.


Possibly conflicting results are also due in some


cases


to sub-total lesions


producing non-standard effects


(Wood,


1958),


in other instances,


species differences.


In addition,


the way in which such terms


as defense,


emotionality,


agonistic


behavior,


and aggressiveness tend to be used in-


terchangeably but measured quite differently does


very


little to clarify


situation.


Electrical stimulation studies have also


, in general,


tended to add


tenuous


support to the contention that the amygdaloid complex is in some


way


associated with emotional reaction (MacLean and Delgado,


1953;


Fondberg and Delgado,


1961;


Wurtz and Olds,


1963;


Hilton and


Zybrozyna,










newer


basolateral division of the amygdala as


being more critical in


such expression than is the older corticomedial portion.


In addition,


there


is evidence


that the amygdala modified


aggressive


behavior through


its influence on the hypothalamus


(Egger and Flynn,


1962; Kling and


Hutt,


1958).


Negative and p


positive


incentives.


In learning


experiments


where


shock has


been used


as a motivational


variable with amygdalectomized


the results


have consistently indicated learning


defects


(King,


1958;


Weiskrantz


Wilson,


1958; Robinson,


1963).


There


is some indica-


tion,


however,


that the deficit may be positively related to


the complex-


ity of the task (Horvath,


1963).


Since amygdalectomy does not signifi-


cantly affect an animal'


retention of an avoidance habit acquired prior


to operation (Weiskrantz,


1956),


the hypothesis,


derived from clinical


data,


that the primary


loss


produced by such lesions


is not


lobal loss


of memory


becomes even more tenable.


Whether amygdalectomized animals


show a learning deficit when


appetitive incentives are used has


type of learning task.


been found to depend


Delayed response learning,


affected by frontal lobe damage


seems


greatly on the


a task significantly


to be unaffected by amygdaloid


lesions


(Pribram and Bagshaw,


1953).


Furthermore,


amygdalectomized


animals


show no deficit in learning simultaneous


and successive visual










A study by Schwartzbaum (1960) utilizing an operant technique has


indicated that amygdalectomized monkeys


show a significant attenuation


of response to changes in magnitude of food reward.


would seem to be quite compatible with


Such a finding


either an earlier observation


that amygdalectomy makes it difficult for animals to identify reinforcing


stimuli (Weiskrantz,


1956) or that amygdalectomy reduces


emotional re-


sponsiveness.


Schwartzbaum appears to prefer the former alternative.


Thus,


he suggests that the attenuation reflects


a loss of ability to dis-


criminatively interrelate different reinforcing


events


rather than a spe-


cific dampening of emotional responsiveness.


Certainly


some type of discrimination factor would have to be posit-


ed in interpreting the deficits


shown by amygdalectomized animals


learning


a transposition problem (Schwartzbaum and Pribram,


1960),


problem in stimulus .equivalence transfer (Bagshaw and Pribram,


1965


a learning set problem (Schwartzbaum and Poulos,


1965).


Hence,


amygdalectomy seems to impair processes


that are involved in deter-


mining certain discriminative


as well


as reinforcing properties of stimu-


Incentive-motivation.


If we assume some motivational factor to be


responsible for the observed attenuation of responsiveness


tomized animals to negative incentives and to shifts


of amygdalec-


in positive incen-










According to Spence (1956),


cues in an alley and goal box are conditioned


to the goal response.


Thus,


the classically conditioned fractional antic-


ipatory goal response tends to be elicited in the presence of these cues.


Stimulus generalization,


then,


provides a mechanism by which the antic


ipatory goal response is evoked at points in the instrumental sequence


prior to the goal response.


The value of the incentive-motivation factor


which is presumed to have a multiplicative relationship with habit


strength,


is seen to be a function of the intensity or vigor


of the antici-


patory goal response.


The intensity of this response


in turn,


a func


tion of the number of reinforced trials,

the magnitude of reinforcement (Spence,


the delay of reinforcement,


1960).


The latter variable has


especially been shown to be significantly related to level of performance


in a straight runway (Crespi,


1942; Zeaman,


1949).


Thus,


runway per-


formance with different reward magnitudes would seem to provide a

reasonable test of any motivational changes produced by brain lesions.


Moreover,


a lack of responsiveness to shift in incentive magnitude can


be viewed as reflecting a disruption of motivational as well as discrim-


native factors.


If loss of incentive-motivation is responsible for atten-


uation of the amygdalectomized


Ss' responsiveness to incentive shift,


this motivational factor should also produce performance deficits prior


to shift.


Hence,


attenuation of response to incentive shift requires in-










Latent extinction.


Latent extinction,


the counterpart of latent


learning,


refers to a reduction in response strength achieved by placing


the animal in the


goal box in the absence of reinforcement (Kimble,


1961).


The phenomenon,


as described by


Kimble,


reflects an extinction


of the


secondary reinforcing properties


ies on latent extinction by


Moltz


of stimuli in the


(1955) and Moltz and Maddi


goal box.


(1956


Stud-

sug-


gest that this phenomenon is


enhanced when the positive goal box is


distinctive and readily discriminable from the non-positive one.


assume


If we


that latent extinction reflects an extinction of the fractional an-


ticipatory


goal response,


we might expect the


process


be enhanced


by distinctive


goal box stimuli.


The conditioning of the anticipatory re-


sponse would appear to be maximal


when goal box cues were distinctive,


and,


hence,


the extinction of the response


would be maximal


when these


distinctive

to occur.


cue s


were present without opportunity for the goal response


Accordingly,


a T maze experiment designed into the present


study maximized the distinctiveness


of the positive


goal box.


Summary and hypotheses.


The bilateral removal of the amygdaloid


complex in a number of different species has


produced similar behav-


ioral changes for


several of the


species.


However,


contradictory and


inconsistent findings have


been frequent enough to warrant a further


check on certain aspects


of the amygdaloidd syndrome"


and the manner










lesions in the


limbic system.


Latency and running


speed measures were obtained in a straight run-


way with two different magnitudes of reward.


Incentive magnitudes were


then shifted.


Acquisition errors and latent extinction


effects


were re-


corded for


maze


performance.


A number of research hypotheses


have


been advanced for the runway and


maze experiments:


with amygdaloid lesions are expected to demonstrate a signif-


icant attenuation of response to incentive


shift in both latency and run-


ning speed. T

Schwartzbaum'


his prediction would seem to be


reasonable in view of


results with amygdalectomized monkeys


in an operant


situation.


The attenuation will be


significantly


greater for


latency than for


running


speed.


Such a difference would be


compatible with a suggestion


that the threshold for initiating a sequence of behavior is


high after


amygdalectomy


(Pribram,


1960).


Amygdalectomized


will be


significantly


less


affected by


tent extinction conditions


than will


the two control groups.


However,


the groups will not differ in terms of acquisition.


If amygdaloid lesions


selectively disrupt classical learning processes,


and hence


the condi-


tioning of the fractional anticipatory


goal response,


the anticipatory re-


sponse


will then be relatively inoperative as a factor that could be










significantly less


Since


latent extinction effect.


studies have not been in agreement concerning the effect of


amygdalectomy on emotionality and food consumption,


it would appear


that no meaningful predictions can be made concerning these variables

in the present study.
















CHAPTER II

METHOD


Subjects.


The Ss were


36 male,


Long Evans


rats


approximately


100 days


old at the time of surgery


They ranged in weight from


99 gm.,


with a mean of 335


These animals,


purchased from R


search Animals Incorporated,


were maintained on a 12 hr.


light-dark


cycle


throughout the course of the experiments.


They


were


placed on


ad libitum food and water pre-operatively and remained on this


for 15 days


schedule


post-operatively.


The animals


were initially divided into three


groups consisting


12 animals per


group.


One


group served as unoperated controls,


anoth-


er received lesions


in the


lateral neocortex,


and bilateral lesions were


made in the amygdaloid complex of animals


in the third group.


Following


fed with


surgery,


five of the amygdalectomized animals


a spoon and eyedropper.


Four of the five


had to be


began eating on the


to 5th post-operative day,


whereas the


5th animal


was


force fed un-


til the


10th post-operative day at which time he died.


Another animal in


the operated control group developed a brain infection,


failed to respond










ficed for histological examination.


Surgery.


Interperitoneal injections of Nembutal were


given based


on a dosage of 60 mg.


of body weight.


This


was


then followed


by a


.12 mg.


injection of atropine sulphate to reduce


respiratory corn-


plications.


The dorsal portion of the head


was


shaved and the external


auditory meatus exposed prior to positioning in a Baltimore stereotaxic


instrument.


An anterior-posterior incision allowed access


to the


skull


from which two lateral sections


were removed with a trephine.


nose


bar was placed 5 mm.


above


the interaural line,


and four


lesions


were


made


bilaterally with


a Grass R/F lesion maker.


A current


set-


ting of 60 for


sec.


was


used.


Coordinates for the amygdaloid lesions


were


(from


bregma)


: anterior-posterior


-.90


-.10,


.70,


and 1. 50 mm.


lateral


4.75,


4.25,


4.00,


4. 00 mm.; ventral


9.00,


9.00,


8.75


mm.


scalp and ear incisions


were


stitched with silk suture,


and approximately 24 hr.


after


surgery each animal


was


given


a 60


unit intramuscular injection of procaine penicillin.


Apparatus.


Running


speed and latency were measured in a straight


alley with a 15


in. entry box,


a 12 in.


start box,


a33


in. runway,


and a


15 in.


goal


box.


The flat black runway and goal box were


in. wide and


in. high.


The entry and start boxes were


in. wide and painted flat


gray.


Both the alley and the


boxes were covered with a 1/4 in.


hard-











Latency and running time were measured electronically to


by separate clocks activated respectively


1/100


by a microswitch on the


sec.


start-


ing gate and


a photoelectric cell positioned


in front of the


start


gate.


second clock


was


stopped by


a microswitch


located under the


floor


of the


goal box.


The single


unit


maze


used to measure acquisition and latent


ex-


tinction


was


modeled after


one used by


Moltz (1955).


The


stem


was


in. and the


top of the


was


Z4 by


Both were painted flat


gray


were


covered


with a 1/4 in.


hardware


cloth.


goal


boxes,


paint-


ed flat black,


were


10 by


10 in.


square and


were


also covered with 1/4


in. hardware


cloth.


The entire


maze


was


covered with


a triple thick-


ness


mize


of cheese


cloth suspended from


the effect of extra-maze visual


suspended directly over the


center


by 4 ft.


cues.


of the 4 ft.


square frame to mini-


A 25 watt light bulb


fr ame.


was


A white melmac


dish


6 in.


in diameter was used


as a food container for the acquisition


and latent extinction


series.


The


King


rating


scale


(1958


was


used to measure the emotionality


or reactivity of the animals.


A sample copy of this


scale


is found in Ap-


pendix


Procedure.


All animals were


given emotionality ratings indepen-


dently by two individuals for five days prior to operations and for three







14


ality ratings were taken for three consecutive days following completion


of the experiment on latent extinction.


The


ratings included,


then,


one


pre-operative and two post-operative measures.


On the


llth post-operative day each animal


was


given a mixture of


laboratory chow and water weighing approximately 200 gm.


of a


At the end


hr. period the dish and remaining food were again weighed and


the difference between initial and second weights


was


recorded.


Seventeen days


after operation all animals were placed


on a


23 hr.


food deprivation schedule on which they were maintained throughout the

remainder of the experiments. Beginning on the 20th post-operative day


the animals were


given four trials daily for


12 consecutive days


in the


straight runway with either a


90 mg.


or a


945 mg.


food reward of 45 mg.


Noyes pellets.

reward were s


At the end of 48 trials the animals


shifted to the large and those


receiving the


receiving the large


small


reward


were


shifted to the


small.


Following this shift in magnitude the animals


were then given 24 additional trials


in the runway at the rate of four per


day.


An intertrial interval of


Tfllfl


was


used for all trials.


Starting


latency and running time were measured electronically for each animal

on each trial.


From 24 to 48 hr.


after completion of the runway experiment all


a animals


were


given 10 trials per day in a


T maze with a 180 mg.


food re-










positive for approximately one-half the


in each group.


A 10 min.


tertrial interval


was used.


Approximately 24 hr.


after completion of


the acquisition


series


five animals from each of the three groups were


assigned to a normal extinction group and six from each of the three


groups to a latent extinction condition.


One animal from the unoperated


control group


was


inadvertently omitted from the latent extinction exper-


iment.


Animals in the latent extinction group were placed in the goal


box with the empty food dish for four


l-min.


periods


separated by


mmi.


intertrial intervals.


Immediately following latent extinction the


were run with a 10 min.


intertrial interval to an extinction criterion of


two errors


in any block of four trials.


Animals in the normal extinction


group which were not placed in the


goal box were


run to the


same cri-


terion using the


same intertrial interval.


The extinction score for each


animal


was


the number of correct responses made before reaching the


extinction criterion.


Histology.


The animals were perfused with isotonic


saline followed


by a 10 per cent formalin solution.


Their


brains were


removed,


embed-


ded in celoidin,


and sectioned at 20 micra.


Every 5th section was


placed on a slide and stained with cresyl violet.


The location and extent


of lesions


was


reproduced on standard rat brain sections which were


then photographed '(see Appendix B).
















CHAPTER III

RESULTS


Runway performance.


Latencie s


and running time measures were


converted to reciprocals.

reciprocal values. Later


Hence,


the graphs and analyses


icy measures obtained with a


945 r


are based on

rig. pre-shift


reward and a


90 mg.


post-shift reward are


summarized in Figure 1.


The mean values are


given for


consecutive


series


of four trials daily.


An analysis of variance of the last pre-shift and the


1st post-shift


ses-


sons,


presented in


Table 1,


indicates no significant differences among


groups.


The incentive-shift effects and the interaction,


however,


are


statistically significant.





















































a,


K.,


S
ED
.4
.4
.4

.4
(0


- 4~)


U)


5-4


m











TABLE


ANALYSIS


OF VARIANCE OF LATENCY


FOR


LAST PRE-SHIFT


SESSION WITH


MG.


REWARD


AND


POST


-SHIFT


SESSION WITH


REWARD


Source d.f. M.S. F P


Between Ss 17

Groups 2 2.9192 .862

Error between Ss 15 3. 3859

Within Ss 18

Incentive-shift 1 19. 5069 10.541 .01(

Incentive-shift X groups 2 7. 1070 3. 840 .05<

Error within Ss 15 1. 8506

Total 35


Figure


shows


reciprocal latency with training on a


90 mg.


reward


schedule


shift to 945 mg.


An analysis


of variance


(Table


2) indi-


cates


that


groups


effect,


the incentive-shift effect,


and the


interaction


are


significant.










TABLE


ANALYSIS OF VARIANCE OF


LATENCY


FOR


LAST PRE-SHIFT


SESSION WITH


MG.


REWARD


AND


1ST POST-SHIFT


SESSION WITH


MG.


REWARD


Source d.f. M.S. F P


Between Ss 15

Groups 2 7.7793 3.2872 .05<

Error between Ss 13 2. 3665

Within Ss 16

Reward magnitude 1 26. 7729 31. 3941 .001<

Reward X groups 2 3. 3505 3. 9288 .01<

Error within Ss 13 8525

Total 31


Means for reciprocals of running time with training on


a 945 mg.


reward and shift to


90 mg.


are


plotted in Figure


An analysis


of vari-


ance


(Table


3) indicates


significance for the incentive-shift and the


groups effect.


Figure 4 shows


running


speed with a shift up in magni-


tude


of reward.


The analysis of variance


(Table 4) indicates


no signifi-


cant group or interaction effect.


It does,


however,


indicate


significance


for the incentive-shift factor.








































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TABLE


ANALYSIS OF VARIANCE OF RUNNING SPEED FOR LAST


PRE-SHIFT SESSION WITH 945


MG.


REWARD AND


1ST POST-SHIFT SESSION WITH 90 MG. REWARD


Source d.f. M.S. F P


Between Ss 17

Groups 2 .286957 12.0879 .01<

Error between Ss 15 .023739

Within Ss 18

Incentive-shift 1 1.476225 39.5362 .001<

Incentive-shift X groups 2 .016919 .4525

Error within Ss 15 .037385

Total 35


An analysis of reward by groups for the last pre-shift session shows

a significant reward effect for latency (Table 5) and a significant inter-


action for running speed (Table 6).


The group effect for latency approach-


es but does not attain statistical significance.

Running speed and latency by trials for the 1st post-shift session


are


presented


in Figure


Since the data on running speed with a 90 mg.


reward seemed to offer the best possibility of a significant interaction,







Amygdaloid


nopera
ortical


lesi


ons


contr
ions


1.00-1
.75-



.50-

.25 -


.5(


I- -


I
-4
5,
I
D I
I


1 2 3 4


1 2


TRIALS


TRIALS


figure


Means


reciprocals


of latency trials


(A and B) and running


.0(










TABLE 4

ANALYSIS OF VARIANCE OF RUNNING SPEED FOR LAST
PRE-SHIFT SESSION WITH 90 MG. REWARD AND
1ST POST-SHIFT SESSION WITH 945 MG. REWARD


Source d.f. M.S. F P


Between Ss 15

Groups 2 .007481 .3188

Error between Ss 13 .023461

Within Ss 16

Incentive-shift 1 .291848 48.4475 .001<

Incentive-shift X groups 2 .003244 .5385

Error within Ss 13 .006024

Total 31



TABLE 5

ANALYSIS OF VARIANCE OF DIFFERENCE SCORES
OF RUNNING SPEED FOR 6TH AND 1ST POST-SHIFT
SESSIONS WITH 90 MG. REWARD



Source d.f. M.S. F P


Between groups 2 .2330 3. 9897 .05<










TABLE 6

ANALYSIS OF VARIANCE OF DIFFERENCE SCORES
OF RUNNING SPEED FOR 6TH AND 1ST POST-SHIFT
SESSIONS WITH 945 MG. REWARD


I
Source d.f. M.S. F P


Between groups 2 .0627 3.7321 .05<

Within groups 13 .0168

Total 15



TABLE 7

ANALYSIS OF VARIANCE OF LATENCY FOR 6TH AND 1ST
POST-SHIFT SESSIONS WITH 945 MG. REWARD




Source d.f. M.S. F P


Between Ss 15

Groups 2 13. 9736 6. 1978 .05<

Error between Ss 13 2. 2546

Within Ss 16

Session 1 1.9801 2.9501

Session X groups 2 1. 2053 1. 7957

Error within Ss 13 .6712










TABLE 8

RANDOM GROUPS ANALYSIS OF VARIANCE OF LATENCY
FOR LAST PRE-SHIFT SESSION


Source d.f. M.S. F P


Reward magnitude 1 63.54 33. 44 .001<

Group 2 6.26 3.29

Reward X group 2 2. 87 1.40

Error 28 1. 90

Total 33


TABLE 9

RANDOM GROUPS ANALYSIS OF VARIANCE OF RUNNING
SPEED FOR LAST PRE-SHIFT SESSION


Source d.f. M.S. F P

Reward magnitude 1 .092011 .6054

Group 2 .068959 .4537

Reward X group ,2 1.507090 9.6170 .01<

Error 28 .156980

Total 33









TABLE


ANALYSIS OF VARIANCE OF INTRASESSION EFFECTS ON RUNNING


SPEED


WITH 90


MG.


REWARD


FOR


1ST POST-SHIFT SESSION


Source d.f. M.S. F P


Trial 3 .401296 5.140 .01<

Groups 2 .261097 3.345 .05<

Trials X groups 6 .043250 .554

Error 60 .078064

Total 71


T maze and latent extinction.


A random analysis of variance for


the number of errors made during the 40 acquisition trials


shows no significant group differences.

tinction data suggests that the amygdala


on the


Although inspection of the


ectomized animals might be


maze


ex-

less


responsive than the other


(Table


groups to the effects of latent extinction


an F test indicates no significant main effects or interaction.


S. error of


7.503,


30 for acquisition;


M.S.


error of 9.156,


d.f.


27 for extinction.)










TABLE 11

MEAN NUMBER OF CORRECT RESPONSES OCCURRING
ON T MAZE IN ACQUISITION AND UNDER NORMAL
AND LATENT EXTINCTION CONDITIONS


Latent Normal
Acquisition Extinction Extinction

Amygdaloid
Lesions 32. 18 6. 67 6.80

Cortical
Lesions 33.55 5.83 8.60

Unoperated
Controls 32.55 5.83 8.40


Emotionality.


Separate analyses were done on difference


scores


tween the pre -operative and 1st post-operative emotionality ratings

(Table 12) and between the pre-operative and 2nd post-operative ratings


(Table 13).


These F tests indicated that there were significant differ-


ences among emotionality scores for the three groups


as shown in Figure










TABLE 12

ANALYSIS OF VARIANCE OF DIFFERENCE IN EMOTIONALITY
SCORES BETWEEN PRE-OPERATIVE AND 1ST POST-
OPERATIVE RATINGS


Source d.f. M.S. F P


Between groups 2 11.257 6.217 .01<

Within groups 30 1. 811

Total 32



TABLE 13

ANALYSIS OF VARIANCE OF DIFFERENCE IN EMOTIONALITY
SCORES BETWEEN PRE-OPERATIVE AND 2ND POST-
OPERATIVE RATINGS



Source d.f. M.S. F P


Between groups 2 10. 5025 4. 171 .05<

Within groups 31 2.5180

Total 33





























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A rank order correlation of


* 25 between posterior extent of amyg-


daloid lesions and the 2nd post-operative emotionality


scores is not sig-


nificant. A

ratings was


n interrater reliability coefficient of


significant


. 96 for emotionality


P< .01).


Food consumption.


Analysis of the data on food consumption indi-


cates that the three groups did not differ


significantly on this variable.


In fact,


the amygdalectomized animals and the operated controls


most identical means of 45. 0


and 45. 76 gm.


had al-


for the amount con-


sumed over the two-day period.


Data summary.


Statistical tests


of the effect of shift in magni-


tude of reward on latency and running


speed show a significant groups


by incentive-shift interaction for


latency under


both


the shift up and


shift down conditions.


incentive shift


groups


interaction for


run-


ning


speed,


however,


is not significant for either


shift condition.


In all


four c

ences


casess

were


the incentive-shift effects are significant,


significant only for


but group differ-


latency with a shift from small to large


reward and for running speed with a shift from large to small reward.


Different:


between the 6th and 1st post-shift sessions for running


indicated significant between groups effects for both the


90 mg.


speed


and the


945 mg.


reward conditions.


Within groups


F tests of reciprocal latency


measures


for the 1st and 6th post-shift sessions indicated a significant











data shows


a significant reward effect on latency and a significant re-


ward by


groups interaction for running speed.


Post-shift intrasession


and group effects


were


significant for


running speed under the


small re-


ward condition,


but there was no significant trials


groups


interaction.


There were no statistically significant differences


between


groups


in terms


of acquisition or


extinction conditions on the


latent


ex-


tinction problem in the


maze,


although


the amygdalectomized


tended to extinguish more rapidly under normal


conditions


and less


rap-


idly under


latent conditions


as compared to the control groups.


Differences


between emotionality


scores


for pre-operative and


1st post-operative ratings and between pre-operative and 2nd post-


operative


ratings were


significant.


There were no significant differences


between groups in terms


of food consumption.















CHAPTER IV

DISCUSSION


Consideration of the


Experimental hypotheses.


The prediction that amygdalectomized animals


would show sig-


nificant attenuation of response in latency and running speed to shifts


magnitude of incentive


measure.


was


confirmed for the former


The attenuation of latencies


suggested by


but not the

Figures 1 a


latter


nd


verified by significant interactions for


groups


by incentive


shift (Tables


1 and


No such significance


was


found for measures


of running speed,


however,


although a comparison of the 1st and


6th post-shift


sessions


did indicate an attenuation effect for


both amygdaloid and cortical lesions


as compared with the unoperated controls


(Figures


and 4).


Further data suggesting an attenuation of latency of response


shift conditions in the amygdalectomized group


was


provided by the ini-


tial and terminal post-shift sessions measures


summarized in Figures


1 and


Although a comparison of latencies for these


sessions


indicated


that


response


data did


suggest


attenuation of the groups did not differ


significantly,


a definite trend of greater attenuation for


amygdalecto-


I C


n







35


attenuation of running speed to incentive shift would suggest that amyg-


dalectomy disrupts the initiation more


than the maintenance of behavior.


Since latency responses were farther removed in time from the goal re-


sponse


than was


running in the alley,


incentive-motivation should have


been more of a determining factor in the


latter


behavior.


Moreover,


the effect of incentive-motivation on running behavior


should have been


enhanced by the fact that the start box


was


gray,


whereas


both the run-


way and


goal box were painted black.


Thus,


the statistical significance


of latency attenuation coupled with the


lack of significance of the run-


nlng


speed attenuation strongly suggested that the deficit


was


not pri-


marily of a motivational nature.


A motivational point of view


was


previously rejected


as an explana-


tion of the response to incentive


shift demonstrated by amygdalectomized


monkeys in an operant situation (Schwartzbaum,


1960).


The alternative


suggested by Schwartzbaum was


loss of ability to interrelate different


reinforcing events


or to respond to one


set of events in terms


of preced-


sets,


an interpretation which appears to complement a sequencing


conception of limbic


system function.


This interpretation would also


seem to be appropriate for the runway data


of the present study.


subnormal running speed of amygdalectomized


incentive prior to shift (Figure


with a large


3) could have reflected a motivational










physiological limit,


since a similar comparative performance level


was


evident for


latency measures


(Figure


Histological data indicated,


moreover,


that this


group sustained more amygdaloid damage than did


the amygdalectomized


trained with


a small incentive.


The lack of any significant group differences in acquisition er-


rors on the


T maze


(Table 11) is


compatible with a number of previous


studies which have indicated that amygdalectomy does


not significantly


impair performance on standard instrumental discrimination tasks


Pribram and Bagshaw,


1953; Schwartzbaum and Pribram,


1960;


Schwartzbaum,


1965).


Other


studies,


however,


have produced results


suggesting that definite acquisition deficits


do occur after amygdalecto-


my when positive incentives


licutt,


are used


1964; Schwartzbaum and Poulos,


(Schwartzbaum,


1965).


Thompson,


Moreover,


Kel-


Horvath


(1963)


, using


a negative incentive with cats,


found that the retardation


effects


of amygdalectomy on acquisition increased noticeably as


tion of complexity or difficulty of the task.


that the failure


It would seem,


to find T maze acquisition differences


a func


therefore,


between groups


the present study might be related to the low level of difficulty of the


task.


The


ease


with which


in all three groups appeared to master the


task would certainly suggest that it was not sufficiently difficult as a

discrimination learning task.










conditions interaction was


significant,


a comparison of the means for


this data suggested that the amygdalectomized


were unresponsive to


the latent extinction procedure.


This


group,


moreover,


tended to ex-


tinguish more rapidly than the other two under normal extinction condi-


tions


This more rapid extinction under normal conditions and less


rapid extinction under


latent conditions might suggest the loss


motivational factor such as incentive-motivation.


tion that the amygdalectomized


In fact,


required approximately 1


of some


the observa-

the same


number of trials to extinguish under latent as under normal conditions

would seem to be explicable only by reference to a motivational construct.


It is possible,


however,


that the normal extinction measures


reflected


non-significant associative rather than motivational differences


terms


of acquisition.


Emotionality.


Although the increase in emotionality observed in the


present experiment (Figure


studies


6) did not parallel the findings


of many other


, it nevertheless agreed with the results of several studies


viously mentioned


1953).


(Bard and Mountcastle,


pre-


1948; Schreiner and Kling,


An explanation frequently advanced to explain instances


of hyper-


emotionality following amygdalectomy is


that the lesions invaded the


ventral hippocampus or in some way altered its


activity.


The present


study,


however,


yielded inconclusive data concerning this hypothesis,







38


posterior extent of amygdaloid lesions did not approach statistical sig-

nificance.


The fact that emotionality


scores


for several of the amygdalecto-


mized animals increased from the 1st post-operative


to the 2nd post-


operative rating


Furthermore,


suggests


a time course change following these lesions.


heightened emotionality did not appear to be


reduced


to any


large extent by handling.


to total emotionality


score


In fact,


for these Ss


the category


was


contributing most


"resistance to handling.


Although the

ly significant, th


lesion effect on emotionality measures


e histological data seemed


was


statistical-


to present no readily


speci-


fiable neurological differentiation for this effect.


The fact remains,


however,


that the amygdalectomized


showed,


without exception,


creases


in emotionality


scores


from the pre-operative


rating to the 1st


post-operative rating.


In addition,


the final rating,


taken after days


handling,


showed slight


decreases


over the pre-operative


ratings for on-


ly three animals


Appendix D


Table


Food consumption.


In the present study,


no significant differences


were found between groups


in amount of food consumed.


Although other


invc


stigators


(Anand and Brobeck,


1952) found that amygdalectomy did


not produce hyperphagia,


Goddard


1964


indicated the most consistent


nicture of amygdaloid removal as


being a transient decrease in food in-











found that amygdalectomy did not increase


hunger or drive for food,


the hyperphagia sometimes


produced by these


lesions would seem to re-


flect something other than enhanced motivational level.


suggests that it


Schwartzbaum


is a general disturbance in habituation processes extend-


ing to classes of stimuli other than food.


The present failure to find any significant effects


of lesions on food


consumption is


possibly due to an inadequate time


operations and the measures


of food consumed.


several of the experimental animals


e lapse between the

As mentioned previous-


had to be force fed for


a period


of time after removal of their


amygdala.


Therefore,


it is


possible that


eating habits


had not been fully reestablished by the


llth post-operative


day at which time the initial food consumption measures were taken.

This early disruption of feeding behavior is further reflected in an aver-


post-operative weight gain of 8. 9 gm.


for the amygdaloid lesion


group


as compared to gains


of 20. 6 and 16


6 gm.


during the same time


period for the cortical lesion and unoperated control


Synthesis.


significant data obtained from the runway experi-


ment tended,


in general,


to support a behavioral sequencing interpreta-


tion of the amygdala and limbic


system.


A finding of significant latency


attenuation plus a lack of such attenuation for running speeds


on the 1st


- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~, ,- .- .... na-- ~an~4n tn ~,,-44C~ 0,r ~at i











initial and the


terminal post-shift sessions did indicate,


however,


a sig-


nificant attenuation effect of both amygdaloid and cortical lesions.


Hence,


the effect as exhibited by running speed would seem to reflect


non-specific


brain damage.


Additional support for an attenuation effect applying exclusively to


amygdalectomized


was provided through a comparison of initial and


terminal post-shift latencies.


Figures


1 and 2 indicated that


with


cortical lesions


did not show the same attenuation effect


as did the amyg-


dalectomized


Equivocal support for a motivational interpretation of amygdaloid


function was provided by the


T maze data,


which suggested a decrease


in resistance to normal extinction and a lack of responsiveness


extinction conditions for amygdalectomized

ed and unoperated controls, the Ss with am


to latent


Compared to the operat-


ygdaloid lesions


extinguished


more slowly under


latent conditions but more rapidly under normal con-


editions.


Although the more rapid extinction under normal


conditions


could reflect an associative factor,


extinction conditions


the lack of responsiveness to latent


seems to be most compatible with a motivational


explanation.


This explanation,


however,


would be in terms


of reduced


motivation,


whereas


the emotionality increases effected by these lesions


mi alit nrnrnnl- ovn rtlxr tb0 nnnnc it nrprli rfi-n


44%, a


t Sit *t &S1 1111** Iitr rz I1 i


n,











between the decrease in reactivity threshold as measured by the King

scale and an increase in sustained motivational level.

The food consumption data did not offer any support for a motiva-


tional interpretation of amygdaloid function.


Perhaps the lack of signif-


icant results obtained for this variable


was


related to the relatively


short time period elapsing between the operations and measures of food

consumption.















CHAPTER

SUMMARY


This


study investigated the effect of amygdaloid and cortical lesions


on the performance of laboratory rats in a straight runway with shifts in

incentive magnitude and on their acquisition and latent extinction scores


in a


maze.


The lesion effects were also evaluated in terms of emo-


tionality changes and amount of food consumed.


The results indicated:


A significant attenuation of shift in starting latency to both in-


crease


and decrease in incentive magnitude


that appeared to be primari-


ly related to the


inability to interrelate different reinforcing events.


A lack of significant attenuation of change


the 1st session after incentive


in running speed for


shift suggesting a negligible disruption of


inc e ntive -motivation.


A significant post-shift sessions effect on running speed, point-


ing to an attenuation for the


cortical lesioned as well as the amygdalec


tomized


This


attenuation as


reflected in the


running speed seeming-


ly represented a non-localized brain damage effect.


A lack of significant differences


between groups in acquisition










A non-significant decrease in resistance


dale ctomized


to extinction of amyg-


under normal conditions which could reflect either a


motivation or an association effect of the lesion.


The lack of respon-


siveness


of the amygdalectomized animals


to latent extinction conditions


would seem to be most compatible with a motivational interpretation.


Significant increases in emotionality produced by amygdalectomy


that were apparently unrelated to any


general increase


in drive level.


. A similarity in quantity of food consumed by amygdalectomized


and control


, perhaps


reflecting short term rather than the final


fects


of amygdaloid lesions on food intake.


runway data


was


viewed


supporting


a sequencing interpreta-


tion of limbic


system function,


whereas the


T maze data,


although not


statistically significant,


was


most compatible with a motivation point of


view.
































APPENDICES











APPENDIX A

SIX RATING SCALES FOR THE STUDY OF EMOTIONALITY


Reaction to Object Presentation:


Pencil is presented close to animal's


snout.
0--Rat ignores pencil
1--Rat alert and attentive,


some body tenseness


--Legs


and body tense and immobile,


vibrissae point forward


3--Scurries away or makes an occasional mild biting attack on pencil
4--Intermediate


5--Very aggressive attack,


disorganized panic,


or violent flight


Response to


Tap on Back


--No reaction
--Twitching or restlessne


--Twitching or


scurrying away


--Jumps or hops


up a bit,


but then settle


down


--Leaps in air and runs about in fright.


-Leaps violently,
to side of cage.


dashes off in panic,


Big hop and movement after
frantic rebounding from side


Resistance to Capture:


Glove is extended forward to animal slowly


and rat is grasped firmly but not roughly.


0--Remains calm,


does not move when approached,


does not struggle


when grasped


1--Remains calm when approached,
when grasped
2--Retreat and moderate struggle


--Retreats when approached,


but scurries away and tugs a bit


struggles vigorously when grasped


--Strong attempt to escape when approached,


is disorganized.


struggles strongly and


Some biting


5--Leaps violently when grasped,


bites frantically,


exceedingly dif-


ficult to catch


Resistance to Handling:


Animal passed from hand to hand for about


30 seconds.


--Relaxes in hand,


does not attempt to escape


1--Restless with some feeble squirming






46


V. Vocalization to Capture and Handling
0- -None
1--Few squeaks
2--Frequent squeaking
3--Frequent squealing-squawking
4--Squealing continuous
5--Frantic and loud screeching continued

VI. Urination and Defecation in Reaction to Handling
0--None
1--Slight urination
2--Few stools
3--Loose stools









APPENDIX B

FRONTAL BRAIN SECTIONS


Animals 1 and


AMYGDALOIDI










FRONTAL BRAIN SECTIONS

Animals 4 and 5










FRONTAL BRAIN SECTIONS

Animals 6 and 8









FRONTAL BRAIN SECTIONS


Animals 21 and


A 21


A22










FRONTAL BRAIN SECTIONS

Animals 31 and 37


A31


C37 CORTICAL










FRONTAL BRAIN SECTIONS


Animals


10 and


C 10









FRONTAL BRAIN SECTIONS

Animals 12 and 13


C12


C13









FRONTAL BRAIN SECTIONS


Animals


14 and


C14


C17










FRONTAL BRAIN SECTIONS


Animals


23 and


A 23








FRONTAL BRAIN SECTIONS

Animals 24 and 26


C24


C26









FRONTAL BRAIN SECTIONS


Animals


33 and 35


C33


C35










APPENDIX C

TABLE 14


MEANS OF RECIPROCALS OF STARTING LATENCY FOR LAST
PRE-SHIFT SESSION WITH 90 MG. REWARD AND 1ST AND
6TH POST-SHIFT SESSIONS WITH 945 MG. REWARD


Animal Number


Last Pre-Shift


1st Post-Shift


6th Post-Shift


Amygdaloid Lesions


4.29
5.55


4.37
4.32


4.21
4.60
22.63


16.25


Cortical Lesions


4.55


4.76
4.59


4.66


18. 32


Unoperated Controls


4.91


4. 21


17.00


7.52
4.98
6.54
34.67


34.87


Sum of Sums


40. 17


69.44


77. 40









STABLE 15

MEANS OF RECIPROCALS OF STARTING LATENCY FOR LAST
PRE-SHIFT SESSION WITH 945 MG. REWARD AND 1ST AND
6TH POST-SHIFT SESSIONS WITH 90 MG. REWARD


Animal Number


Last Pre-Shift


1st Post-Shift


6th Post-Shift


Amygdaloid Lesions


4.46


3. 76
23.95


22.23


12.86


Cortical Lesions


4.56


6.01


30.41


4.58
24.90


22.05


Unoperated Controls

2


4.50
4.47


4.59


38.27


19.00


18.38


Sum of Sums


92.63


66. 13


53.29











TABLE 16

MEANS OF RUNNING SPEED FOR LAST PRE-SHIFT SESSION
WITH 90 MG. REWARD AND 1ST AND 6TH POST-SHIFT
SESSIONS WITH 945 MG. REWARD


Animal Number


Last Pre -Shift


1st Post-Shift


6th Post-Shift


Amygdaloid Lesions


.792
.902
.610


.654


1.007


1.05


1.005
1.030
.718
.961
.814
4.528


.831
.804


4.297


Cortical Lesions


.870
.479
.837
.722
.587


.964
.855


1.204


.760


.989
.857
.814
.892
.777


4. 585


4.329


Unoperated Controls


.670
.583
.666
.740
.687
.581


3.927


.895


.816
.788


.974
.809
.894


1.027
.924
1.182
.924
1. 165
6. 117


Sum of Sums


10.970


14.026


14.974











TABLE 17

MEANS OF RUNNING SPEED FOR LAST PRE-SHIFT SESSION
WITH 945 MG. REWARD AND 1ST AND 6TH POST-SHIFT
SESSIONS WITH 90 MG. REWARD


Animal Number


Last Pre-Shift


1st Post-Shift


6th Post-Shift


Amygdaloid Lesions


.374
.417
.693
.738
.669
.672


.227
.210
.328
.256
.110
.247


.605
.790
.632
.655
.415
.072


3.563


Cortical


Lesions


.843
.824
.812
1.042
1.076
.725


.357
.419
.308
.233
.742


.313
2.372


.703
.713
.619
.777


.359


4.114


Unoperated Controls


.707


.290
.755
.749
.743


.330
.548
.614


.792
3. 159


.441
.253
.503
.521
.685
.616


Sum of Sums


14. 199


6. 909


10. 302










TABLE 18

RECIPROCALS OF RUNNING TIME BY TRIALS
FOR 1ST POST-SHIFT SESSION

Trials


Amygdaloid Lesions


.185
.200
.671
.521
.267
.337


2. 181


.272
.129
.411
.211
.056
.417


1.496


.279
.084
.027
.225
.085


.172
.429
.204
.068
.032
.040
.945


.195
.895


Cortical Lesions


.610
.869
.704
.153
.980


.274
.435
.050
.308


.057


. 127
.274
.227


.417
.099
.252
.339
.098
.308
1.513


.909


.621
3.937


.267
1.936


Unoperate i


r entrols


.893
.351
1.219
.135


.575


.461
3.634


Sum


.847


.901
1.000
.134


.034
.617


.094
.372
.909
.021
.025


.360
.833
.042
.035
.037
. 128
1.435


.114
1.535


of Sums










APPENDIX D

TABLE 19

MEAN EMOTIONALITY SCORES FOR PRE-OPERATIVE
RATING AND TWO POST-OPERATIVE RATINGS


Animal Number


Pre-Operative


Post-Operative
Pre -Training


Post-Operative
Post-Training


Amygdaloid Lesions

1


10.35
10.35
6.05


9.45
9.00
8.40
6.50
6.95
8.65


11.58
10.67


9.90


7.40
9.60


10.41
10.08


6.65
10.60


11.00


9.75


Cortical Lesions


7. 10


5. 10


7.83
6.17
5.92
7.08


8.00
8.80
5.00
6.50
7.05


13.25
10.25
6.50


6.80
5.45


9.10


7.33
11.08


6.65
died









APPENDIX E

TABLE 20


RANK ORDER OF POSTERIOR EXTENT OF


AMYGDALOID


LESIONS AND ANTERIOR-POSTERIOR EXTENT IN MICRA


Rank of Posterior


Anterior-Posterior


Animal Number


Extent


Extent


1900
2700
2400


2100
1600
2000


10.0


1400















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L.,















BIOGRAPHICAL SKETCH


Wilbur


Alan


Thomas


was


born July


1929 in LaBelle,


Florida.


was


graduated from LaBelle High School in 1947,


1951 until 1953 in the Armed Forces of the


United Stat


and served from

es. He received


his B. S


. and M. A.


degrees from the


University of Florida in 1955 and


1957


was


employed as a psychologist by the Georgia State Institu-


tion for


Mentally


Retarded at Gracewood from 1958 to


1961.


He returned


to graduate


school in 1961 and pursued graduate studies


until the fall


1963.


From 1963


to the present he has


been employed


as assistant pro-


fessor


of psychology by


Rollins College


in Winter


Park,


Florida.


is married to the former


Miss Frances


Marie Glover and they have four


children.










This dissertation was prepared under the direction of the chairman


of the candidate's supervisory committee and has


been approved by all


members of that committee.


It was


submitted to the


Dean of the College


of Arts


nnd Sciences and to the Graduate Council,


and was approved


partial fulfillment of the requirements for the degree of Doctor


of Philo-


sophy.


December


1966


ean


Scien


Dean,


Graduate School


Supervisory Committee:


Chairm


7 .


an


-a4 ys> ~&~z~c~


1V
































UNIVERSITY OF FLORIDA
II i 1 26i I5 III III
3 1262 08554 1141