Rabinak Christine A, MacNamara Annmarie, Kennedy Amy E, Angstadt Mike, Stein Murray B, Liberzon Israel, Phan K Luan
Mental Health Service, Veteran's Administration Ann Arbor Healthcare System, Ann Arbor, Michigan; Department of Psychiatry, University of Michigan, Ann Arbor, Michigan.
Depress Anxiety. 2014 Oct;31(10):851-61. doi: 10.1002/da.22243. Epub 2014 Feb 22.
Collectively, functional neuroimaging studies implicate frontal-limbic dysfunction in the pathophysiology of posttraumatic stress disorder (PTSD), as reflected by altered amygdala reactivity and deficient prefrontal responses. These neural patterns are often elicited by social signals of threat (fearful/angry faces) and traumatic reminders (combat sounds, script-driven imagery). Although PTSD can be conceptualized as a disorder of emotion dysregulation, few studies to date have directly investigated the neural correlates of volitional attempts at regulating negative affect in PTSD.
Using functional magnetic resonance imaging and a well-validated task involving cognitive regulation of negative affect via reappraisal and known to engage prefrontal cortical regions, the authors compared brain activation in veterans with PTSD (n = 21) and without PTSD (n = 21, combat-exposed controls/CEC), following military combat trauma experience during deployments in Afghanistan or Iraq. The primary outcome measure was brain activation during cognitive reappraisal (i.e., decrease negative affect) as compared to passive viewing (i.e., maintain negative affect) of emotionally evocative content of aversive images
The subjects in both groups reported similar successful reduction in negative affect following reappraisal. The PTSD group engaged the dorsolateral prefrontal cortex (dlPFC) during cognitive reappraisal, albeit to a lesser extent than the CEC group. Although the amygdala was engaged in both groups during passive viewing of aversive images, neither group exhibited attenuation of amygdala activation during cognitive reappraisal.
Veterans with combat-related PTSD showed less recruitment of the dlPFC involved in cognitive reappraisal, suggesting focal and aberrant neural activation during volitional, self-regulation of negative affective states.
功能性神经影像学研究表明，创伤后应激障碍（PTSD）的病理生理学涉及额叶 - 边缘系统功能障碍，杏仁核反应性改变和前额叶反应不足即反映了这一点。这些神经模式通常由威胁的社会信号（恐惧/愤怒面孔）和创伤性提示（战斗声音、脚本驱动的意象）引发。尽管PTSD可被视为一种情绪调节障碍，但迄今为止，很少有研究直接调查PTSD中调节负面影响的意志性尝试的神经相关性。
作者使用功能磁共振成像和一项经过充分验证的任务，该任务涉及通过重新评估对负面影响进行认知调节，并且已知会激活前额叶皮质区域。作者比较了在阿富汗或伊拉克部署期间经历军事战斗创伤后，患有PTSD的退伍军人（n = 21）和未患有PTSD的退伍军人（n = 21，战斗暴露对照/CEC）的大脑激活情况。主要结局指标是与被动观看（即维持负面影响）厌恶图像的情感唤起内容相比，认知重新评估期间（即减少负面影响）的大脑激活情况。
两组受试者在重新评估后均报告负面情绪有类似的成功减少。PTSD组在认知重新评估期间激活了背外侧前额叶皮质（dlPFC），尽管程度低于CEC组。虽然两组在被动观看厌恶图像时杏仁核均被激活，但在认知重新评估期间两组均未表现出杏仁核激活的减弱。
与战斗相关的PTSD退伍军人在参与认知重新评估的dlPFC募集较少，这表明在负面情绪状态的意志性自我调节过程中存在局部和异常的神经激活。
