Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
PLoS One. 2012;7(8):e42560. doi: 10.1371/journal.pone.0042560. Epub 2012 Aug 31.
Studies addressing posttraumatic stress disorder (PTSD) have demonstrated that PTSD patients exhibit structural abnormalities in brain regions that relate to stress regulation and fear responses, such as the hippocampus, amygdala, anterior cingulate cortex, and ventromedial prefrontal cortex. Premotor cortical areas are involved in preparing to respond to a threatening situation and in representing the peripersonal space. Urban violence is an important and pervasive cause of human suffering, especially in large urban centers in the developing world. Violent events, such as armed robbery, are very frequent in certain cities, and these episodes increase the risk of PTSD. Assaultive trauma is characterized by forceful invasion of the peripersonal space; therefore, could this traumatic event be associated with structural alteration of premotor areas in PTSD?
METHODOLOGY/PRINCIPAL FINDINGS: Structural magnetic resonance imaging scans were acquired from a sample of individuals that had been exposed to urban violence. This sample consisted of 16 PTSD patients and 16 age- and gender-matched controls. Psychometric questionnaires differentiated PTSD patients from trauma-exposed controls with regard to PTSD symptoms, affective, and resilience predispositions. Voxel-based morphometric analysis revealed that, compared with controls, the PTSD patients presented significant reductions in gray matter volume in the ventral premotor cortex and in the pregenual anterior cingulate cortex.
Volume reduction in the premotor cortex that is observed in victims of urban violence with PTSD may be associated with a disruption in the dynamical modulation of the safe space around the body. The finding that PTSD patients presented a smaller volume of pregenual anterior cingulate cortex is consistent with the results of other PTSD neuroimaging studies that investigated different types of traumatic events.
研究表明，创伤后应激障碍（PTSD）患者的大脑中与应激调节和恐惧反应相关的区域存在结构异常，如海马体、杏仁核、前扣带回和腹内侧前额叶皮质。运动前皮质区域参与准备对威胁情况做出反应以及代表个人空间。城市暴力是人类痛苦的一个重要且普遍的原因，尤其是在发展中国家的大型城市中心。在某些城市，武装抢劫等暴力事件非常频繁，这些事件增加了 PTSD 的风险。攻击性创伤的特征是个人空间的强力入侵；因此，这种创伤性事件是否与 PTSD 患者运动前区的结构改变有关？
方法/主要发现：对曾遭受过城市暴力的个体进行了结构磁共振成像扫描。该样本包括 16 名 PTSD 患者和 16 名年龄和性别匹配的对照。心理测量问卷将 PTSD 患者与创伤暴露对照组区分开来，评估 PTSD 症状、情感和适应力倾向。体素形态计量学分析显示，与对照组相比，PTSD 患者的腹侧运动前皮质和前扣带回皮质的灰质体积明显减少。
患有 PTSD 的城市暴力受害者的运动前皮质体积减少可能与身体周围安全空间的动态调节中断有关。PTSD 患者前扣带回皮质的体积较小，这与其他研究不同类型创伤性事件的 PTSD 神经影像学研究结果一致。
