First Advisor

Miranda M. Lim

Date of Award


Document Type


Degree Name

Bachelor of Science (B.S.) in Psychology and University Honors




Post-traumatic stress disorder, Brain damage, Comorbidity, Fear




Traumatic Brain Injury (TBI) and Post-Traumatic Stress Disorder (PTSD) have been studied extensively. However, there is little research examining the interaction between the two. An understanding of this interaction is considered important because it is a common comorbid diagnosis. In this study, we use a mouse model to look at how TBI+PTSD interact to influence contextual fear learning, generalization, and extinction. We employed Controlled Cortical Impact (CCI) and Single Prolonged Stress (SPS) as models of TBI and PTSD, respectively. Fear conditioning and PTSD involve overlapping neural pathways including the amygdala, hippocampus, and medial prefrontal cortex which makes contextual fear conditioning an ideal method for investigating fear learning and behavior in a controlled setting. Four groups (Control, TBI, PTSD, and TBI+PTSD) were analyzed for differences in fear expression during conditioning, context generalization, and fear extinction tests. Although all groups acquired fear equally during fear conditioning, the PTSD group showed increased fear expression during the test for generalization, suggesting a decreased ability to discriminate between aversive and neutral contextual stimuli. Results from extinction tests performed suggest significantly impaired recall of conditioned fear among the TBI+PTSD group in comparison to controls. During fear extinction tests all groups were able to significantly extinguish fear. Ongoing research will further characterize the behavioral phenotype of the combined TBI+PTSD mouse model.


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