NeuroBehavioral Research Lab, Department of Veteran Affairs Medical Center, New Jersey Health Care System, East Orange, New Jersey, USA; Graduate School of Biomedical Sciences, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey, USA.
NeuroBehavioral Research Lab, Department of Veteran Affairs Medical Center, New Jersey Health Care System, East Orange, New Jersey, USA.
Behav Brain Res. 2019 Aug 5;368:111913. doi: 10.1016/j.bbr.2019.111913. Epub 2019 Apr 15.
Psychiatric disorders affect nearly 50% of individuals who have experienced a traumatic brain injury (TBI). Anhedonia is a major symptom of numerous psychiatric disorders and is a diagnostic criterion for depression. It has recently been appreciated that reinforcement may be separated into consummatory (hedonic), motivational and decisional components, all of which may be affected differently in disease. Although anhedonia is typically assessed using positive reinforcement, the importance of stress in psychopathology suggests the study of negative reinforcement (removal or avoidance of aversive events) may be equally important. The present study investigated positive and negative reinforcement following a rat model of mild TBI (mTBI) using lateral fluid percussion. Hedonic value and motivation for reinforcement was determined by behavioral economic analyses. Following mTBI, the hedonic value of avoiding foot shock was reduced. In contrast, the hedonic value of escaping foot shock or obtaining a sucrose pellet was not altered by mTBI. Moreover, motivation to avoid or escape foot shock or to acquire sucrose was not altered by mTBI. Our results suggest that individuals experiencing mTBI find avoidance of aversive events less reinforcing, and therefore are less apt to utilize proactive control of stress.
精神障碍影响近 50%的创伤性脑损伤（TBI）患者。快感缺失是许多精神障碍的主要症状，也是抑郁症的诊断标准。最近人们认识到，强化可以分为消费（享乐）、动机和决策成分，所有这些成分在疾病中可能受到不同的影响。尽管快感缺失通常是通过正强化来评估的，但压力在精神病理学中的重要性表明，对负强化（消除或避免不愉快的事件）的研究可能同样重要。本研究使用侧方流体冲击建立了轻度 TBI（mTBI）大鼠模型，探讨了正性和负性强化。通过行为经济学分析确定了强化的享乐价值和动机。mTBI 后，避免足部电击的享乐价值降低。相比之下，mTBI 并未改变逃避足部电击或获得蔗糖丸的享乐价值。此外，mTBI 并未改变逃避或逃避足部电击或获得蔗糖的动机。我们的结果表明，经历 mTBI 的个体发现避免不愉快的事件的强化作用降低，因此不太可能利用主动控制压力。
