Perturbations in Risk/Reward Decision Making and Frontal Cortical Catecholamine Regulation Induced by Mild Traumatic Brain Injury

Behav Brain Res. 2024 Apr 16:115002. doi: 10.1016/j.bbr.2024.115002. Online ahead of print.ABSTRACTMild traumatic brain injury (mTBI) disrupts cognitive processes that influence risk taking behavior. Little is known regarding the effects of repetitive mild injury (rmTBI) or whether these outcomes are sex specific. 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. The present study characterized the effects of rmTBI on risk/reward decision making behavior and catecholamine transmitter regulatory proteins within the PFC. Rats were exposed to sham, single (smTBI), or three closed-head controlled cortical impact (CH-CCI) injuries and assessed for injury-induced effects on risk/reward decision making using a probabilistic discounting task (PDT). In the first week post-final surgery, mTBI increased risky choice preference. By the fourth week, males exhibited increased latencies to make risky choices following rmTBI, demonstrating a delayed effect on processing speed. When levels of tyrosine hydroxylase (TH) and the norepinephrine reuptake transporter (NET) were measured within subregions of the PFC, females exhibited dramatic increases of TH levels within the orbitofrontal cortex (OFC) following smTBI. However, both males and females demonstrated reduced levels of OFC NET following rmTBI. Th...

Source: Behavioural Brain Research - April 18, 2024 Category: Neurology Authors: Christopher P Knapp Eleni Papadopoulos Jessica A Loweth Ramesh Raghupathi Stan B Floresco Barry D Waterhouse Rachel L Navarra Source Type: research