Handy Justin D, Wright W Geoffrey, Haskell Amanda, Servatius Labeeby, Servatius Richard J
Department of Veterans Affairs, Syracuse Veterans Affairs Medical Center, Syracuse, NY, United States.
Central New York Research Corporation, Syracuse, NY, United States.
Front Behav Neurosci. 2020 Dec 8;14:595007. doi: 10.3389/fnbeh.2020.595007. eCollection 2020.
Enhanced acquisition of eyeblink conditioning is observed in active duty military and veterans expressing PTSD symptoms (PTSD) and those expressing temperamental vulnerabilities to develop PTSD after traumatic experiences, such as behaviorally inhibited temperament. There is a growing literature showing persistent cerebellar abnormalities in those experiencing mild traumatic brain injury (mTBI) as well as linkages between mTBI and PTSD. With the dependency of eyeblink conditioning on cerebellar processes, the impact of mTBI on eyeblink conditioning in veterans expressing PTSD is unknown. The present study assessed eyeblink conditioning in veterans during two sessions separated by 1 week. With a focus on the accelerated learning of veterans expressing PTSD, training utilized a protocol which degrades learning through interspersing conditioned stimulus (CS) exposures amongst delay-type trials of CS and unconditional stimulus (US) co-terminating trials. Faster acquisition of the eyeblink conditioned responses (CR) was observed in PTSD during Week 1. The Week 2 assessment revealed an interaction of mTBI and PTSD, such that asymptotic performance of PTSD was greater than PTSD among mTBI veterans, whereas these groups did not differ in mTBI veterans. To further examine the relationship between enhanced sensitivity to acquire eyeblink conditioning and PTSD, cluster analysis was performed based on performance across training sessions. Those with enhanced sensitivity to acquire eyeblink conditioned responses expressed more PTSD symptoms, which were specific to Cluster C symptoms of avoidance, in addition to greater behavioral inhibition. These results support the continued investigation of the conditioned eyeblink response as a behavioral indicator of stress-related psychopathology.
在现役军人和表现出创伤后应激障碍（PTSD）症状的退伍军人，以及在经历创伤性事件（如行为抑制性气质）后表现出易患PTSD气质脆弱性的人群中，观察到眨眼条件反射的习得增强。越来越多的文献表明，轻度创伤性脑损伤（mTBI）患者存在持续的小脑异常，以及mTBI与PTSD之间的联系。由于眨眼条件反射依赖于小脑过程，mTBI对表现出PTSD的退伍军人眨眼条件反射的影响尚不清楚。本研究在间隔1周的两个阶段评估了退伍军人的眨眼条件反射。以表现出PTSD的退伍军人的加速学习为重点，训练采用了一种方案，该方案通过在条件刺激（CS）和无条件刺激（US）共终止试验的延迟型试验中穿插CS暴露来降低学习效果。在第1周，PTSD患者眨眼条件反应（CR）的习得更快。第2周的评估显示mTBI与PTSD之间存在相互作用，即mTBI退伍军人中PTSD的渐近表现大于无PTSD者，而在无mTBI的退伍军人中，这些组没有差异。为了进一步研究对眨眼条件反射习得的增强敏感性与PTSD之间的关系，基于整个训练阶段的表现进行了聚类分析。对眨眼条件反应习得具有增强敏感性的人表现出更多的PTSD症状，除了更强的行为抑制外，这些症状还特定于回避的C类症状。这些结果支持继续将条件性眨眼反应作为应激相关精神病理学的行为指标进行研究。
