Date Approved


Embargo Period


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)


Cell Biology and Neuroscience


Rowan-Virtua School of Translational Biomedical Engineering & Sciences


Rachel Navarra, Ph.D.

Committee Member 1

Daniel Chandler, Ph.D.

Committee Member 2

Barry Waterhouse, Ph.D.

Committee Member 3

Daniel Manvich, Ph.D.

Committee Member 4

Corina Bondi, Ph.D.


traumatic brain injury


Brain; Cognition


Medical Sciences | Medicine and Health Sciences | Neurosciences


Mild traumatic brain injury (mTBI) disrupts cognitive processes that influence risk taking behavior; however, the effects of repetitive mild injury (rmTBI) or whether these outcomes are sex specific are unknown. Risk/reward decision making is mediated by the prefrontal cortex (PFC), which is densely innervated by catecholaminergic fibers. Aberrant PFC catecholamine activity has been documented following TBI and may underlie TBI-induced risky behavior. Here, we exposed rats to sham (no injury), single, or three closed-head controlled cortical impact (CH-CCI) injuries to characterize the effects of rmTBI on 1) risk/reward decision making behavior using a probabilistic discounting task (PDT) and 2) levels of catecholamine regulatory proteins within subregions of the PFC using Western blot analysis. Mild TBI transiently increased risky choice preference, more prominently in females. Additionally, rmTBI produced delayed effects on response speed in males only. Mild TBI increased tyrosine hydroxylase (TH) levels in females only, but reduced norepinephrine transporter (NET) levels in both sexes within the orbitofrontal cortex (OFC), indicating this subregion is susceptible to catecholamine instability after mTBI. Overall, the CH-CCI model of mTBI has revealed time-dependent and sex-specific changes in risk/reward decision making and catecholamine regulation following mild head injuries.

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