Stress-enhanced fear learning: an animal model for studying post-traumatic stress disorder in male and female subjects

Undergraduates: Eric Brandon Kelly, n/a Meghan Jones Donald Lysle n/a

Faculty Advisor: Donald Lysle
Department: Psychology & Neuroscience

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Post-Traumatic Stress Disorder (PTSD) is a debilitating mental disorder imposing severe fiscal and emotional costs on society. Current treatments for PTSD include cognitive and exposure therapies, and EMDR, but no FDA approved pharmaceutical treatment. One goal of our laboratory is to understand the neurobiological mechanisms driving PTSD to identify potential targets for the development of novel pharmaceutical treatments. To this end, we employ an animal model of PTSD, stress-enhanced fear learning (SEFL). SEFL is based on foot shock fear conditioning, but is a maladaptive form of hyperractive fear. In the model, a severe stressor changes how a future mild stressor is processed and induces generalized anxiety-like behavior. We have reliably established this model in our laboratory but, traditionally, have relied exclusively on male subjects, and post-stress behavioral patterns differ between male and female rats. The study's aim was to optimize the SEFL model for female subjects. Interestingly, in Experiment 1, female subjects did not exhibit enhanced fear learning to the mild stressor with the same stress parameters as male subjects. However, in Experiment 2, we showed that with an increase in the severity of the milk stressor, female subjects exhibited significant SEFL, comparable to male subjects. Using this model, we can study the neurobiological mechanisms driving PTSD in female and male subjects, and can explore potential sex differences in the neurobiology of PTSD.