Right temporal cortical hypertrophy in resilience to trauma: an MRI study

In studies employing physiological measures such as magnetic resonance imaging (MRI), it is often hard to distinguish what constitutes risk-resilience factors to posttraumatic stress disorder (PTSD) following trauma exposure and what the effects of trauma exposure and PTSD are. We aimed to investigate whether there were observable morphological differences in cortical and sub-cortical regions of the brain, 7–8 years after a single potentially traumatic event. Twenty-four participants, who all directly experienced the 2004 Indian Ocean Tsunami, and 25 controls, underwent structural MRI using a 3T scanner. We generated cortical thickness maps and parcellated sub-cortical volumes for analysis. We observed greater cortical thickness for the trauma-exposed participants relative to controls, in a right lateralized temporal lobe region including anterior fusiform gyrus, and superior, middle, and inferior temporal gyrus. We observed greater thickness in the right temporal lobe which might indicate that the region could be implicated in resilience to the long-term effects of a traumatic event. We hypothesize this is due to altered emotional semantic memory processing. However, several methodological and confounding issues warrant caution in interpretation of the results. Following a traumatic event, most people do not develop long-lasting trauma-related symptoms.In a group who experienced a traumatic event 8 years prior, but showed low levels of trauma-related symptoms, we observed increased cortical thickness in the right temporal lobe.The right temporal lobe is implicated in emotional semantic memory processing, and thus might be associated with resilience to the long-term effects of a traumatic event. Following a traumatic event, most people do not develop long-lasting trauma-related symptoms. In a group who experienced a traumatic event 8 years prior, but showed low levels of trauma-related symptoms, we observed increased cortical thickness in the right temporal lobe. The right temporal lobe is implicated in emotional semantic memory processing, and thus might be associated with resilience to the long-term effects of a traumatic event.

在采用磁共振成像（Magnetic Resonance Imaging, MRI）等生理测量手段的研究中，人们往往难以区分创伤暴露后哪些因素构成创伤后应激障碍（Posttraumatic Stress Disorder, PTSD）的风险与韧性影响因素，同时也难以厘清创伤暴露本身及PTSD所产生的效应究竟为何。本研究旨在探究单次潜在创伤性事件发生7~8年后，受试者大脑皮层及皮层下区域是否存在可观测的形态学差异。本研究纳入24名曾直接经历2004年印度洋海啸的受试者与25名对照受试者，所有受试者均接受了3T扫描仪下的结构磁共振成像扫描。我们生成了皮层厚度图谱，并对皮层下脑区体积进行分区以用于后续分析。结果显示，相较于对照受试者，经历创伤的受试者在右侧偏侧化的颞叶区域（包括前梭状回、颞上回、颞中回及颞下回）表现出更大的皮层厚度。我们在右侧颞叶观测到更大的皮层厚度，这提示该脑区可能与创伤事件长期效应的韧性调控相关。我们推测这一现象源于情绪性语义记忆加工过程的改变。然而，本研究存在若干方法学及混淆变量相关问题，因此对结果的解读需持谨慎态度。创伤事件发生后，多数人群并不会出现长期的创伤相关症状。在8年前曾经历创伤性事件但创伤相关症状水平较低的受试者组中，我们观测到右侧颞叶的皮层厚度有所增加。右侧颞叶与情绪性语义记忆加工过程相关，因此可能与创伤事件长期效应的韧性调控存在关联。创伤事件发生后，多数人群并不会出现长期的创伤相关症状。在8年前曾经历创伤性事件但创伤相关症状水平较低的受试者组中，我们观测到右侧颞叶的皮层厚度有所增加。右侧颞叶与情绪性语义记忆加工过程相关，因此可能与创伤事件长期效应的韧性调控存在关联。