Date of Award

Spring 1-1-2011

Document Type


Degree Name

Master of Arts (MA)


Psychology & Neuroscience

First Advisor

Serge Campeau

Second Advisor

Robert Spencer

Third Advisor

Susan Patterson


While habituation develops to repeated predicable psychological stress, manipulating certain parameters of the stress experience may lead to disruption of a stressor's predictability and subsequent dishabituation of the stress response. In this experiment, we investigated whether behavioral, endocrine, and neural responses (indicators of activity of the Limbic-Hypothalamic-Pituitary-Adrenal-, or LHPA-, axis) to psychological stress (restraint) differ when the duration of stress given on test day violates expectations based on prior stress experience. Rats experienced daily restraint on Days 1-4 followed by either the same duration or a longer duration of restraint on Day 5. In conclusion, habituation of the endocrine and behavioral stress responses occurred when the duration of the stressor matches previous experience, while dishabituation occurred (with remarkable temporal precision) following an unpredicted increase in stress duration.