Date of Award

Spring 1-1-2011

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology & Neuroscience

First Advisor

Steven F. Maier

Second Advisor

Ryan K. Bachtell

Third Advisor

Christopher A. Lowry

Abstract

Acute, traumatic, stress is an experiential factor that can predispose an individual to the development of psychiatric disorders such as depression and post-traumatic stress disorder. However, not all individuals react similarly to traumatic events. This variability has led to the study of the components that can mitigate the unwanted consequences of stress. One component that potently modulates the consequences of stress is stressor controllability. Indeed, uncontrollable, but not controllable, stress produces a variety of behaviors that have been termed anxiety- or depression-like. The studies herein elucidate a mechanism that could explain the behavioral differences following uncontrollable and controllable stress. We found that uncontrollable stress functionally impairs serotonin-1A receptors in the dorsal raphe nucleus, while controllable stress does not. Furthermore, this protective effect of control was mediated by the medial prefrontal cortex. Finally, an initial experience with controllable stress prevented subsequent uncontrollable stress-induced impairments of serotonin-1A receptor function. These results indicate that activation of the medial prefrontal cortex produces both short- and long-term resistance to some of the consequences of stress.

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