Xie Haiyan, Guo Qinger, Duan Jinfeng, Jia Xize, Zhou Weihua, Sun Haozhe, Fang Ping, Yang Hong
Department of Psychiatry, The Fourth Affiliated Hospital, College of Medicine, Zhejiang University, Yiwu, China.
Department of Radiology, The Fourth Affiliated Hospital, College of Medicine, Zhejiang University, Yiwu, China.
Front Psychiatry. 2022 May 18;13:858768. doi: 10.3389/fpsyt.2022.858768. eCollection 2022.
Major depressive disorder (MDD) has been demonstrated to be associated with abnormalities in neural networks. However, few studies examined information flow in the salience network (SN). This study examined abnormalities in the causal connectivity between the SN and whole brain in drug-naive first-episode patients with MDD in the resting state.
Based on the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) diagnostic criteria, 23 drug-naive first-episode MDD patients and 20 matched healthy individuals were recruited and underwent a resting-state magnetic resonance scan. The acquired functional image data were preprocessed using resting-state functional magnetic resonance imaging (rs-fMRI) data analysis toolkit plus (RESTplus). Then, using the data processing & analysis for brain imaging (DPABI) software and a coefficient-based general component analysis method with the right anterior insula (rAI) as the region of interest (ROI), the causal connectivity of the SN with the whole brain and its correlation with cognitive and mental performance were examined in the resting state.
(1) The MDD group showed a significantly higher Hamilton Depression Rating Scale total score and significantly higher scores for anxiety, cognitive disturbance, and block factors compared with normal controls. (2) Compared with control: from whole brain to the rAI, the MDD group showed a lower causal connectivity in the left inferior frontal gyrus; from the rAI to the whole brain, the MDD group showed a lower causal connectivity in the right cingulate gyrus, the right precuneus, and extending to paracentral lobule but higher causal connectivity in the left inferior and middle frontal gyrus. (3) In the MDD group, from rAI to the whole brain, the causal connectivity values for the right cingulate gyrus/precuneus were negatively correlated with the score of Stroop Color-Word Test A, B, and C as well as interference times.
Our results indicated disrupted causal connectivity among the default mode network (DMN), the central executive network (CEN), and SN in drug-naive first-episode MDD patients. Especially, our results suggest a unique role for rAI in the ordered or hierarchical information processing, presumed to include bottom-up and top-down reciprocal influences among the three networks in MDD.
重度抑郁症（MDD）已被证明与神经网络异常有关。然而，很少有研究考察突显网络（SN）中的信息流。本研究考察了未服用过药物的首发MDD患者静息状态下SN与全脑之间因果连接的异常情况。
根据《精神疾病诊断与统计手册》（DSM-5）诊断标准，招募了23名未服用过药物的首发MDD患者和20名匹配的健康个体，并进行静息态磁共振扫描。使用静息态功能磁共振成像（rs-fMRI）数据分析工具包升级版（RESTplus）对采集到的功能图像数据进行预处理。然后，使用脑成像数据处理与分析（DPABI）软件以及以右侧前岛叶（rAI）为感兴趣区域（ROI）的基于系数的一般成分分析方法，在静息状态下考察SN与全脑的因果连接及其与认知和心理表现的相关性。
（1）与正常对照组相比，MDD组的汉密尔顿抑郁评定量表总分显著更高，焦虑、认知障碍和阻滞因子得分也显著更高。（2）与对照组相比：从全脑到rAI，MDD组在左侧额下回的因果连接较低；从rAI到全脑，MDD组在右侧扣带回、右侧楔前叶以及延伸至中央旁小叶的因果连接较低，但在左侧额下和额中回的因果连接较高。（3）在MDD组中，从rAI到全脑，右侧扣带回/楔前叶的因果连接值与Stroop色词测验A、B和C的得分以及干扰次数呈负相关。
我们的结果表明，未服用过药物的首发MDD患者的默认模式网络（DMN）、中央执行网络（CEN）和SN之间的因果连接中断。特别是，我们的结果表明rAI在有序或分层信息处理中具有独特作用，推测这包括MDD中三个网络之间的自下而上和自上而下的相互影响。
