The effect of neonatal testosterone propionate (TP) (100 ug/day for the first 5 days of life or 1.25 mg. on day 1 of birth) injections on the acquisition of both active and passive avoidance was studied. Testing was initiated during both the prepubescent and adult periods of life. Neonatal TP injections facilitated the acquisition of active avoidance responding prior to puberty and also in adulthood. Neonatal TP injections had no effect on passive avoidance responding. A number of physiological (body, gonadal and adrenal weights) and behavioural (activity, shock sensitivity) measures were also studied to investigate their possible role in influencing our results. The TP injections led to significantly lower gonadal weights in the TP-injected group. Prior to puberty the TP-injected animals also possessed heavier adrenal glands, and were more active than the control group. The TP-injected group also had lower shock thresholds than the control group. The results suggest that excess neonatal TP injections affect an organism's ability to acquire an active avoidance response. The exact mechanism by which TP injections have their effect is unknown at this time. Future research would help to clarify whether the effect of excess neonatal TP is directly on the associative process or indirectly through a number of other factors, investigated in this article. Paradoxically, increased activity would be expected to interfere with the acquisition of passive avoidance behaviour, but this did not prove to be the case as TP injected animals acquired this response just as well or slightly better than controls. The observed differences between groups on shock reactivity measures suggest another plausible explanation of the results. Neonatal TP injections could facilitate acquisition of an active avoidance response by increasing sensitivity to the motivational stimulus. This possibility becomes even more tenable when we consider that other investigators have found a positive correlation between shock sensitivity and learning an active avoidance response (Beatty et. al. 1970, Pare, 1969). Specifically, these investigators have found that females acquire an active avoidance response faster than males and also have lower reactivity thresholds to footshock than males. Our finding of lowered shock sensitivity following neonatal TP injections would appear to parallel these observations and suggests shock sensitivity may be making an important contribution to the active avoidance data. / Arts, Faculty of / Psychology, Department of / Graduate

No description available.

published_or_final_version / Clinical Psychology / Doctoral / Doctor of Psychology

Dissertation (Ph. D.)--University of Akron, Dept. of Psychology-Industrial/Organizational Psychology, 2009. / "May, 2009." Title from electronic dissertation title page (viewed 12/2/2009) Advisor, Aaron M. Schmidt; Committee members, Rosalie J. Hall, Paul E. Levy, Yang Lin, Robert G. Lord; Department Chair, Paul E. Levy; Dean of the College, Chand Midha; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

No description available.

Learned taste avoidance (LTA) was studied by allowing rats to drink a novel sweet solution followed by induction of gastric malaise (training). When the solution was presented again (test), normal rats reduced their consumption. Ultrasonic vocalizations indicated that the rats experienced positive affect during training which shifted to negative affect during the test. Basolateral amygdala lesions eliminated the LTA and the negative affective shift when the rats were 23 hr water deprived during both training and test suggesting amygdala-based Pavlovian conditioning, but only attenuated the LTA and eliminated the aversive shift when the rats were 3 hr deprived on the test, suggesting instrumental learning. When rats were 3 h deprived during training the lesions had no effect on either the LTA or the negative affective shift, suggesting an amygdala-independent form of LTA based on latent learning.

Several investigations suggest that the amygdala plays a significant role in behavioral inhibition. Brutkowski, Fonberg and Mempel (1960) reported that bilateral lesions of the amygdaloid complex in dogs severely impaired inhibitory conditioned responses, while excitatory conditioned responses remained unaffected. Bilateral lesions of the amygdala have also been shown to impair the acquisition of the conditioned emotional response (Kellicutt & Schwartzbaum, 1963), and the retention of an auditory frequency discrimination in a bar pressing situation for food (Schwartzbaum, Thompson & Kellicutt, 1964). In the latter study, amygdaloid lesioned rats typically persisted in responses that were no longer adaptive, that is, they increased responding under nonreinforced conditions. [...]

Thesis (B.Sc.Hons.) -- University of Adelaide, Department of Psychology, 1972.

Thesis (M.A.) -- Memorial University of Newfoundland. / Typescript. Bibliography : leaves 40-47. Also available online.

Thesis (M.A.) -- Memorial University of Newfoundland. / Typescript. Bibliography : leaves 47-50. Also available online.