Date of Award


Degree Type


Degree Name

Master of Science (MS)




Traumatic brain injury (TBI) affects millions of people in the U.S. each year. This thesis worked to address anxiety, a common emotional symptom following TBI, by utilizing a five-hit repeat mild TBI (rmTBI) experimental model. First, changes in gonadal status following injury and the severity of anxiety symptoms experienced were investigated. Our data revealed that suppressed testosterone levels following rmTBI resulted in significantly more anxiety-like behaviors across several observational variables. Even more, some of these behaviors were reduced by providing testosterone supplementation immediately following injury.Another goal of this work was to investigate the role of mitochondrial dysfunction, measured by COX4i1 mRNA expression within dopaminergic neurons in a key region involved in the anxiety neurocircuitry, the medial amygdaloid nucleus. Interestingly, tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis, was increased within the medial amygdaloid nucleus following injury. No significant changes in COX4i1 expression were found in this specific brain region.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.