Rangaprakash D, Deshpande Gopikrishna, Daniel Thomas A, Goodman Adam M, Robinson Jennifer L, Salibi Nouha, Katz Jeffrey S, Denney Thomas S, Dretsch Michael N
AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama.
Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, California.
Hum Brain Mapp. 2017 Jun;38(6):2843-2864. doi: 10.1002/hbm.23551. Epub 2017 Mar 15.
Military service members risk acquiring posttraumatic stress disorder (PTSD) and mild-traumatic brain injury (mTBI), with high comorbidity. Owing to overlapping symptomatology in chronic mTBI or postconcussion syndrome (PCS) and PTSD, it is difficult to assess the etiology of a patient's condition without objective measures. Using resting-state functional MRI in a novel framework, we tested the hypothesis that their neural signatures are characterized by functionally hyperconnected brain regions which are less variable over time. Additionally, we predicted that such connectivities possessed the highest ability in predicting the diagnostic membership of a novel subject (top-predictors) in addition to being statistically significant.
U.S. Army Soldiers (N = 87) with PTSD and comorbid PCS + PTSD were recruited along with combat controls. Static and dynamic functional connectivities were evaluated. Group differences were obtained in accordance with our hypothesis. Machine learning classification (MLC) was employed to determine top predictors.
From whole-brain connectivity, we identified the hippocampus-striatum connectivity to be significantly altered in accordance with our hypothesis. Diffusion tractography revealed compromised white-matter integrity between aforementioned regions only in the PCS + PTSD group, suggesting a structural etiology for the PCS + PTSD group rather than being an extreme subset of PTSD. Employing MLC, connectivities provided worst-case accuracy of 84% (9% more than psychological measures). Additionally, the hippocampus-striatum connectivities were found to be top predictors and thus a potential biomarker of PTSD/mTBI.
PTSD/mTBI are associated with hippocampal-striatal hyperconnectivity from which it is difficult to disengage, leading to a habit-like response toward episodic traumatic memories, which fits well with behavioral manifestations of combat-related PTSD/mTBI. Hum Brain Mapp 38:2843-2864, 2017. © 2017 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.
军人有患创伤后应激障碍（PTSD）和轻度创伤性脑损伤（mTBI）的风险，且共病率很高。由于慢性mTBI或脑震荡后综合征（PCS）与PTSD的症状重叠，若没有客观测量方法，很难评估患者病情的病因。在一个新的框架中使用静息态功能磁共振成像，我们检验了这样一个假设，即它们的神经特征表现为功能上过度连接的脑区，且这些脑区随时间变化较小。此外，我们预测，除了具有统计学意义外，这种连接性在预测新受试者的诊断类别（顶级预测指标）方面具有最高能力。
招募了患有PTSD以及共病PCS + PTSD的美国陆军士兵（N = 87），并设置了战斗对照组。评估了静态和动态功能连接性。根据我们的假设得出组间差异。采用机器学习分类（MLC）来确定顶级预测指标。
从全脑连接性来看，我们发现海马体 - 纹状体连接性根据我们的假设发生了显著改变。扩散张量成像显示，仅在PCS + PTSD组中，上述区域之间的白质完整性受损，这表明PCS + PTSD组存在结构病因，而非PTSD的极端亚型。采用MLC，连接性提供了84%的最坏情况准确率（比心理测量方法高9%）。此外，发现海马体 - 纹状体连接性是顶级预测指标，因此是PTSD/mTBI的潜在生物标志物。
PTSD/mTBI与海马体 - 纹状体的过度连接有关且难以摆脱，导致对情景性创伤记忆产生类似习惯的反应，这与战斗相关PTSD/mTBI的行为表现非常吻合。《人类大脑图谱》38:2843 - 2864，2017年。© 2017作者。《人类大脑图谱》由威利期刊公司出版。
