创伤后应激障碍“闪回”症状的脑功能网络纵向研究

Posttraumatic stress disorder (PTSD) is a severe and debilitating mental illness, but its pathological mechanism is far from clear. Because the three symptom clusters of PTSD may be involved in different mechanism, and PTSD has a high comobidity with depression, many neuroimaging studies achieved inconsistent results. Moreover, most of these findings lack of specificity and are similar with what found in depression studies. Therefore, this study selected "flashback", the typical core symptom of PTSD as the phenotype. Resting state and task-based fMRI, and diffusion kurtosis imaging (DKI) technique will be used integratively to test the default mode network, salience network, and the white matter connectivity of traffic accident survivors within one week after trauma. Meanwhile, the correlation between brain function and "flashback" severity will also be evaluated. Furthermore, longitudinal trajectories of structure and function of the functional brain networks will be detected in 12 month follow-up. The impact of posttraumatic cognition on "flashback" symptom and its interaction with brain network will also be assessed. Moreover, health volunteer and major depression patients will be recruited as controls to help find specific abnormality of functional brain network of PTSD. The purpose of this study is to clarify the brain network basis of "flashback" symptom and its functional and structural alteration during the development of PTSD. If the expected results be achieved, it will further promote the deep understanding of the pathological mechanisms of PTSD.

创伤后应激障碍(PTSD)是一种高致残率的精神疾病，但其病理机制远未阐明。由于PTSD三大症状群可能涉及不同的发生机制及该病与抑郁的高共病率，导致许多神经影像学研究结果差异较大，且与抑郁症研究的结果相似，缺乏特异性。因此，本研究选择PTSD特征性的核心症状"闪回"为研究表型，综合运用静息态与任务态fMRI及扩散峰度成像(DKI)技术在创伤一周内即对交通事故者"默认网络"与"突显网络"的功能活动与白质连接进行检测，并评估与"闪回"症状的关系；通过为期12月的随访，检测脑功能网络的结构与功能随时间纵向变化的轨迹，并评估创伤后认知等因素对"闪回"症状的影响及与脑功能网络的交互关系；同时，通过与健康对照、抑郁症对照的比较，寻找PTSD特异性的脑功能网络异常，以期阐明"闪回"症状发生的神经网络基础及在PTSD发生发展中网络功能与结构的改变。如能够获得预期结果将进一步促进对PTSD病理机制的深入理解。

创伤后应激障碍(PTSD)致残率高，目前仍缺乏有效干预手段，其病理机制也远未阐明。近年来神经影像研究发现PTSD患者默认网络等脑网络功能存在异常, 但由于缺乏前瞻性研究，无法明确脑网络异常与PTSD的因果关系。本研究采用前瞻性的研究设计，入组交通事故幸存者95例(其中有效数据74例)，采用3.0T高场MRI技术对包括突显网络在内的脑功能网络进行研究，并进行为期6月的随访，同时综合评定其临床特征。结果显示：.（1）创伤急性期PTSD组患者突显网络分布范围显著少于对照组；.（2）创伤急性期PTSD组在前扣带束、上纵束等脑白质FA值显著低于对照组；.（3）两侧前额叶VMHC值降低，同时发现连接两侧前额叶区域的胼胝体膝部FA值下降；.（4）PTSD组与创伤对照组在基线及6月随访时BDNF水平并无显著性组间差异，并发现PTSD组基线与随访时BDNF水平无差异，创伤对照组BDNF随访较基线有显著性升高，提示BDNF可能是预防PTSD发病的保护性因子