Li Liyuan, Wang YiFeng, Ye Liangkai, Chen Wang, Huang Xinju, Cui Qian, He Zongling, Liu Dongfeng, Chen Huafu
The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China.
School of Life Science and Technology, Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu, China.
Front Psychiatry. 2019 Mar 4;10:84. doi: 10.3389/fpsyt.2019.00084. eCollection 2019.
Generalized anxiety disorder (GAD) is characterized by a chronic, continuous symptom of worry and exaggerated startle response. Although functional abnormality in GAD has been widely studied using functional magnetic resonance imaging (fMRI), the dynamic signatures of GAD are not fully understood. As a vital index of brain function, brain signal variability (BSV) reflects the capacity of state transition of neural activities. In this study, we recruited 47 patients with GAD and 38 healthy controls (HCs) to investigate whether or not BSV is altered in patients with GAD by measuring the standard deviation of fMRI signal of each voxel. We found that patients with GAD exhibited decreased BSV in widespread regions including the visual network, sensorimotor network, frontoparietal network, limbic system, and thalamus, indicating an inflexible brain state transfer pattern in these systems. Furthermore, the correlation between BSV and trait anxiety score was prone to be positive in patients with GAD but negative in HCs. The opposite relationships between BSV and anxiety level in the two groups indicate that the brain with moderate anxiety level may stay in the most stable rather than in the flexible state. As the first study of BSV in GAD, we revealed extensively decreased BSV in patients with GAD similar to that in other mental disorders but with a non-linear relationship between BSV and anxiety level indicating a novel neurodynamic mechanism of the anxious brain.
广泛性焦虑障碍（GAD）的特征是长期持续的担忧症状和夸张的惊吓反应。尽管已使用功能磁共振成像（fMRI）对GAD的功能异常进行了广泛研究，但GAD的动态特征尚未完全了解。作为脑功能的重要指标，脑信号变异性（BSV）反映了神经活动状态转换的能力。在本研究中，我们招募了47名GAD患者和38名健康对照者（HCs），通过测量每个体素的fMRI信号标准差来研究GAD患者的BSV是否发生改变。我们发现，GAD患者在包括视觉网络、感觉运动网络、额顶网络、边缘系统和丘脑在内的广泛区域表现出BSV降低，表明这些系统中的脑状态转移模式缺乏灵活性。此外，GAD患者中BSV与特质焦虑评分之间的相关性倾向于呈正相关，而在HCs中呈负相关。两组中BSV与焦虑水平之间的相反关系表明，中度焦虑水平的大脑可能处于最稳定而非灵活的状态。作为对GAD中BSV的首次研究，我们发现GAD患者的BSV广泛降低，这与其他精神障碍类似，但BSV与焦虑水平之间存在非线性关系，这表明了焦虑大脑的一种新的神经动力学机制。
