Cisler Josh M, Bush Keith, Scott Steele J, Lenow Jennifer K, Smitherman Sonet, Kilts Clinton D
Brain Imaging Research Center, Psychiatric Research Institute, University of Arkansas for Medical Sciences, USA.
Computer Science, Engineering and Information Technology, University of Arkansas at Little Rock, USA.
J Psychiatr Res. 2015 Apr;63:75-83. doi: 10.1016/j.jpsychires.2015.02.014. Epub 2015 Feb 24.
Current neurocircuitry models of PTSD focus on the neural mechanisms that mediate hypervigilance for threat and fear inhibition/extinction learning. Less focus has been directed towards explaining social deficits and heightened risk of revictimization observed among individuals with PTSD related to physical or sexual assault. The purpose of the present study was to foster more comprehensive theoretical models of PTSD by testing the hypothesis that assault-related PTSD is associated with behavioral impairments in a social trust and reciprocity task and corresponding alterations in the neural encoding of social learning mechanisms. Adult women with assault-related PTSD (n = 25) and control women (n = 15) completed a multi-trial trust game outside of the MRI scanner. A subset of these participants (15 with PTSD and 14 controls) also completed a social and non-social reinforcement learning task during 3T fMRI. Brain regions that encoded the computationally modeled parameters of value expectation, prediction error, and volatility (i.e., uncertainty) were defined and compared between groups. The PTSD group demonstrated slower learning rates during the trust game and social prediction errors had a lesser impact on subsequent investment decisions. PTSD was also associated with greater encoding of negative expected social outcomes in perigenual anterior cingulate cortex and bilateral middle frontal gyri, and greater encoding of social prediction errors in the left temporoparietal junction. These data suggest mechanisms of PTSD-related deficits in social functioning and heightened risk for re-victimization in assault victims; however, comorbidity in the PTSD group and the lack of a trauma-exposed control group temper conclusions about PTSD specifically.
目前创伤后应激障碍（PTSD）的神经回路模型聚焦于介导对威胁的过度警觉以及恐惧抑制/消退学习的神经机制。对于解释与身体或性侵犯相关的PTSD患者中观察到的社交缺陷和再次受侵害风险增加的关注较少。本研究的目的是通过检验以下假设来促进对PTSD更全面的理论模型：与攻击相关的PTSD与社交信任和互惠任务中的行为损伤以及社交学习机制的神经编码的相应改变有关。患有与攻击相关PTSD的成年女性（n = 25）和对照女性（n = 15）在MRI扫描仪外完成了一个多轮信任游戏。这些参与者中的一部分（15名PTSD患者和14名对照）还在3T功能磁共振成像期间完成了一项社交和非社交强化学习任务。定义并比较了两组之间编码价值期望、预测误差和波动性（即不确定性）的计算模型参数的脑区。PTSD组在信任游戏中的学习速度较慢，社交预测误差对后续投资决策的影响较小。PTSD还与前扣带回膝周和双侧额中回中负面预期社交结果的更强编码，以及左侧颞顶叶交界处社交预测误差的更强编码有关。这些数据表明了PTSD相关社交功能缺陷以及攻击受害者再次受侵害风险增加的机制；然而，PTSD组的共病情况以及缺乏创伤暴露对照组使得关于PTSD的结论受到限制。
