中文摘要：

目的 探究抑郁症患者在识别悲伤表情时执行控制网络中脑区的相互作用机制,并以此探讨抑郁症患者悲伤情绪处理异常的可能机制.方法 利用脑磁图（MEG）检测20例抑郁症患者及20例相匹配的健康对照者在识别动态面部表情时的脑部反应.根据既往先验知识,选取的感兴趣脑区包括初级视觉皮层、眶额回、背外侧前额叶、前扣带回建立竞争模型.通过动态因果模型方法选出最优模型,并比较抑郁症组与对照组的效能连接变化.结果 贝叶斯模型选择结果显示,最优模型为模型1（模型超越概率为0.80）;最优模型特征为初级视觉皮层、前扣带回、眶额回、背外侧前额叶之间两两存在自下而上的调制连接.效能连接参数比较发现,在调制连接水平上,抑郁症患者左侧半球前眶额回到前扣带回及背外侧前额叶之间的效能连接显著性减弱（t=-2.93,P=0.0057;t=-2.73,P=0.0096）.右侧半球眶额回到背外侧前额叶之间的效能连接显著性减弱,差异具有统计学意义（t=-3.01,P=0.0046）.结论 抑郁症患者前额叶执行控制网络存在异常,眶额回与背外侧前额叶及前扣带回之间的效能连接减弱,这可能与抑郁症患者不能有效处理负性信息有关.

英文摘要：

Objective To investigate the interconnection of the executive control network in major depressive disorder when they recognized the sad facial stimuli,and to discuss the aberrant mechanism of emotion processing.Methods Twenty major depressive patients and 20 well-matched healthy volunteers participated in the experiment.The brain actions of all subjects were recorded by the magnetoencephalography （MEG） when they were required to distinguish the emotion face.Based on prior knowledge,the interested brain area consisted of the primary visual cortex （V1）,the orbitofrontal cortex（OFC）,the dorsolateral prefrontal cortex （DLPFC）,the anterior cingulated cortex （ACC）.Then constructing three competing models to select an optimal model by the method of dynamic causal model（DCM）,finally the differences of the effective connections of the optimal model between the depressed patients and healthy controls were analyzed.Results According to the results of Bayesian model selection （BMS）,model 1 had the most exceedance probability of 0.80 with the features that there were bidirectional modulatory connections between the OFC,ACC and DLPFC.Given the best model,the parameters of effective connectivity of the optimal model were extracted,and then two-sample t-test over the model 1 was adopted.The modulatory effective connectivity from the OFC to the DLPFC in both hemisphere（t=-2.73,P=0.0096;t=-3.01,P=0.0046） and the OFC to the ACC （t=-2.93,P=0.0057） in the left hemisphere were significantly reduced in MDD.Conclusion There exists abnormal function of executive control network in depressed patients,the decreased effective connections between the OFC and the DLPFC,as well as the OFC and the ACC,may have correlation with the negative