Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, People's Republic of China.
PLoS One. 2010 Dec 22;5(12):e15238. doi: 10.1371/journal.pone.0015238.
The amygdala is often found to be abnormally recruited in social anxiety disorder (SAD) patients. The question whether amygdala activation is primarily abnormal and affects other brain systems or whether it responds "normally" to an abnormal pattern of information conveyed by other brain structures remained unanswered. To address this question, we investigated a network of effective connectivity associated with the amygdala using Granger causality analysis on resting-state functional MRI data of 22 SAD patients and 21 healthy controls (HC). Implications of abnormal effective connectivity and clinical severity were investigated using the Liebowitz Social Anxiety Scale (LSAS). Decreased influence from inferior temporal gyrus (ITG) to amygdala was found in SAD, while bidirectional influences between amygdala and visual cortices were increased compared to HCs. Clinical relevance of decreased effective connectivity from ITG to amygdala was suggested by a negative correlation of LSAS avoidance scores and the value of Granger causality. Our study is the first to reveal a network of abnormal effective connectivity of core structures in SAD. This is in support of a disregulation in predescribed modules involved in affect control. The amygdala is placed in a central position of dysfunction characterized both by decreased regulatory influence of orbitofrontal cortex and increased crosstalk with visual cortex. The model which is proposed based on our results lends neurobiological support towards cognitive models considering disinhibition and an attentional bias towards negative stimuli as a core feature of the disorder.
杏仁核在社交焦虑障碍(SAD)患者中常被发现异常活跃。杏仁核的激活是主要异常并影响其他大脑系统,还是对其他大脑结构传递的异常信息模式做出“正常”反应,这个问题仍然没有答案。为了解决这个问题,我们使用静息态功能磁共振成像数据的格兰杰因果分析,对 22 名 SAD 患者和 21 名健康对照者(HC)的杏仁核相关有效连接网络进行了研究。使用 Liebowitz 社交焦虑量表(LSAS)研究了异常有效连接和临床严重程度的影响。与 HC 相比,SAD 患者的颞下回(ITG)对杏仁核的影响降低,而杏仁核和视觉皮层之间的双向影响增加。LSAS 回避评分和格兰杰因果值的负相关提示 ITG 到杏仁核的有效连接减少具有临床相关性。我们的研究首次揭示了 SAD 核心结构异常有效连接的网络。这支持了影响情感控制的预定模块失调的观点。杏仁核处于功能障碍的中心位置,其特征是眶额皮层的调节影响降低,与视觉皮层的串扰增加。基于我们的结果提出的模型为考虑抑制解除和对负面刺激的注意力偏向作为该障碍核心特征的认知模型提供了神经生物学支持。