The Brain Network Patterns Of Emotional Faces Processing Task And Resting State For The First-Episode, Treatment-Naive Patients With Major Depressive Disorder

Objective:(1)Using first-episode,treatment-naive young adults with major depressive disorder as subjects, we try to eliminate the effects of confounding factors such as comorbidities,duration of disease,and drugs,and to explore the emotional processing dysfunction and the aberrant brain network connectivity in patients with depression.(2)We respectively explore the emotional faces processing related network and default mode network patterns in first-episode, treatment-naive young adults with major depressive disorder, and discuss the abnormal distribution of both networks,as well as the relationship between the two networks.(3)On the basis of the whole brain connectivity analysis,we use the multi-voxel pattern analysis method to explore the abnormal functional connectivity of depression, and study the regional and the whole brain network change in first-episode, treatment-naive young adults with major depressive disorder from the macro level.Methods:(1)Using implicit emotional faces processing task, fMRI data of29first-episode, treatment-naive young adults with major depressive disorder and32gender-,age-, and education level matched normal subjects were collected. General linear model analysis was used to explore the brain activation and deactivation patterns under emotional faces processing task.(2)The distribution of default mode network for depression group and normal group was extracted by independent component analysis (ICA) and comparing with task-related network. Correlation analysis was conducted between the aberrant default mode network areas of first-episode, treatment-naive young adults with major depressive disorder and their behavior scores.(3)For the same29patients with depression and33normal controls,resting state fMRI data were collected.The whole brain functional connectivity was calculated for both groups, and multi-voxel pattern analysis was implied to classify the first-episode, treatment-naive young adults with major depressive disorder from normal controls using the whole brain functional connectivity as features.Results:(1)As behavioral results suggested, no significant difference exists between the depression group and normal group on the reaction time of gender judgment for emotional faces, but there exist a borderline significant interaction effects of group and emotional type. First-episode, treatment-naive young adults with major depressive disorder showed faster response to gender judgment for emotional faces only except for sad faces.(2)As general linear model analysis results suggested, compared to normal group, patients with depression showed deactivation to negative emotions face (including fearful,sad, and angry faces).Different emotion caused different abnormal deactivation patterns: sad faces caused deactivation in the precuneus,cerebellum and lingual gyrus;fearful faces and angry faces caused similar abnormal deactivation patterns, including hippocampus, parahippocampal gyrus, cerebellum and lingual gyrus.Compared to rest block, task caused activations in bilateral cuneus, frontal lobe,superior parietal lobule and deactivations in bilateral superior parietal gyrus, superior frontal gyrus, anterior cingulate in normal group;similar activations in cuneus and frontal lobe and deactivations in bilateral parietal lobe, medial prefrontal cortex, anterior gyrus and superior temporal gyrus were found in patients with depression.(3)As independent component analysis results suggested, there were a lot of overlapping regions between task reduced network and default mode network for both groups, mainly including the medial prefrontal cortex, ventral anterior cingulate,and precuneus.There was also some overlap between anti-correlated default mode network and task induced network, such as right precuneus for normal group and right middle frontal gyrus for depression group.Compared to the normal controls, the default mode network of first-episode, treatment-naive young adults with major depressive disorder showed decreased functional connectivity in bilateral prefrontal areas.According to the results of correlation analysis, the left superior frontal gyrus in decreased default network areas for patients with depression was negatively correlated with the score of maladaptive cognitive emotional regulation strategies.(4)As multi-voxel pattern analysis results suggested, the choice of400whole brain functional connectivity as features achieve the best generalization performance, with the generalization rate of91.9%by linear kernel support vector machine classifier at confidence level of p<.0001.There were272consensus features, and631participatory features, with50.4±1.2%of features with positive Kendall correlation coefficient, suggesting that patients with depression showed decreased functional connectivity compared to the normal controls.The consensus features located mainly in:the default mode network (such as the medial prefrontal cortex, angular gyrus, superior parietal gyrus,inferior parietal gyrus), central executive network (such as dorsolateral prefrontal cortex), affective network (such as superior temporal gyrus, cingulate cortex, basal ganglia, cerebellum), visual cortex (such as fusiform gyrus,lingual gyrus,superior occipital gyrus,calcarine gyrus),sensory-motor cortex (such as precentral gyrus,postcentral gyrus, paracentral lobule,supply motor area).The most weighted brain area included orbitofrontal cortex, cerebellum, visual cortex, etc.Conclusions:(1)First-episode,treatment-naive young adults with major depressive disorder showed aberrant brain activation pattern on emotional faces processing task. This may be related with impaired cognitive inhibition process in patients with depression, reflecting mood-congruent processing bias and attentional disengagement difficulties in depression, and leading to decreased activation in brain regions associated with cognitive emotional regulation.Patients with depression showed decreased bilateral prefrontal connectivity in the default network under emotional processing task, which was correlated with negative cognitive emotional regulation strategy. This may imply that the patients with major depression have insufficient internal monitoring ability and functional damage related to emotional cognitive regulation.(2)Based on multi-voxel pattern anaylsis,first-episode,treatment-naive young adults with major depressive disorder are well identified from normal people by linear support vector machine classifier, which suggests the whole brain functional connectivity under the resting state can be used as potential effective biomarkers in clinical diagnosis of depression. The most discriminative whole brain functional connectivity features are mainly located in the default network, cognitive control network, affective network, and visual cortex, which support the common neural pathway theory of mood disorders from previous studies.These brain networks contain overlapping anatomical regions and functionally influence each other. Therefore, it is important to analysis the characteristics of various functional brain networks from an integral perspective, which would help to further understand the pathogenesis of depression and its related clinical symptoms.