Clinical Psychology Unit, Department of Psychology, University of Wuppertal, Wuppertal, Germany.
PLoS One. 2013;8(3):e58150. doi: 10.1371/journal.pone.0058150. Epub 2013 Mar 25.
Notwithstanding some discrepancy between results from neuroimaging studies of symptom provocation in posttraumatic stress disorder (PTSD), there is broad agreement as to the neural circuit underlying this disorder. It is thought to be characterized by an exaggerated amygdalar and decreased medial prefrontal activation to which the elevated anxiety state and concomitant inadequate emotional regulation are attributed. However, the proposed circuit falls short of accounting for the main symptom, unique among anxiety disorders to PTSD, namely, reexperiencing the precipitating event in the form of recurrent, distressing images and recollections. Owing to the technical demands, neuroimaging studies are usually carried out with small sample sizes. A meta-analysis of their findings is more likely to cast light on the involved cortical areas. Coordinate-based meta-analyses employing ES-SDM (Effect Size Signed Differential Mapping) were carried out on 19 studies with 274 PTSD patients. Thirteen of the studies included 145 trauma-exposed control participants. Comparisons between reactions to trauma-related stimuli and a control condition and group comparison of reactions to the trauma-related stimuli were submitted to meta-analysis. Compared to controls and the neutral condition, PTSD patients showed significant activation of the mid-line retrosplenial cortex and precuneus in response to trauma-related stimuli. These midline areas have been implicated in self-referential processing and salient autobiographical memory. PTSD patients also evidenced hyperactivation of the pregenual/anterior cingulate gyrus and bilateral amygdala to trauma-relevant, compared to neutral, stimuli. Patients showed significantly less activation than controls in sensory association areas such as the bilateral temporal gyri and extrastriate area which may indicate that the patients' attention was diverted from the presented stimuli by being focused on the elicited trauma memory. Being involved in associative learning and priming, the retrosplenial cortex may have an important function in relation to trauma memory, in particular, the intrusive reexperiencing of the traumatic event.
尽管创伤后应激障碍（PTSD）症状诱发的神经影像学研究结果存在一些差异，但对于该障碍的神经回路存在广泛共识。人们认为，这种障碍的特征是杏仁核过度活跃，内侧前额叶活动减少，而升高的焦虑状态和随之而来的情绪调节不足归因于此。然而，所提出的回路并不能解释 PTSD 的主要症状，即反复出现痛苦的图像和回忆，以重现创伤事件。由于技术要求，神经影像学研究通常采用小样本量进行。对这些发现进行荟萃分析更有可能揭示涉及的皮质区域。采用 ES-SDM（效应大小符号差异映射）对 19 项研究进行了基于坐标的荟萃分析，这些研究共涉及 274 名 PTSD 患者。其中 13 项研究包括 145 名创伤暴露对照参与者。对与创伤相关的刺激的反应与对照条件的比较以及对与创伤相关的刺激的反应的组间比较进行了荟萃分析。与对照和中性条件相比，PTSD 患者在对与创伤相关的刺激的反应中显示出中线后扣带回和楔前叶的显著激活。这些中线区域与自我参照处理和突出的自传体记忆有关。与中性刺激相比，PTSD 患者的前扣带回回前部和双侧杏仁核对与创伤相关的刺激表现出过度激活。与对照组相比，患者在双侧颞叶和外纹状体等感觉联想区域的激活明显减少，这可能表明患者的注意力被集中在诱发的创伤记忆上，而不是被呈现的刺激所分散。后扣带回皮层参与联想学习和启动，与创伤记忆有关，特别是对创伤事件的侵入性再体验，可能具有重要功能。
