MRI Studies Of Depression In Acute And Remitted State In Anterior Cingulate Cortex

Anterior cingulate cortex(ACC)plays an essential role in the pathophysiology of major depressive disorder(MDD)and antidepressant treatment.Besides,ACC has heterogenous functions and is involved in both cognitive and emotion functions.However,few previous studies had explored whether there exists distinct functional disrupted pattern in different regions of ACC.In this study,resting state functional magnetic resonance imaging(f MRI)data were used to focus on the anterior cingulate cortex(ACC)to explore whether there are different disrupted patterns as regards to cognitive and emotional function in different subregions,and the relationship between the impairment and the recovery area after antidepressant treatment.The main research contents were as follows:1.Exploring whether ACC has subregions with different disrupted patterns.Using k-means clustering,subdivisions with variable impairment were identified based on groups’ dissimilarity value between MDD patients before treatment and healthy control(HC)on functional connectivity(FC)between each voxel of ACC and four regions of interests(bilateral dorsolateral prefrontal cortex(DLPFC)and amygdalae).ACC was subdivided into three impairment subdivisions named as Medial ACC,Distal ACC and Lateral ACC according to their dominant locations.Further statistical analysis showed significant decrease of MDD patients before treatment compared to HC in FC between Distal ACC and left DLPFC,between Lateral ACC and bilateral amygdalae(p<0.05).After treatment,only impaired FC between Lateral ACC and left amygdala kept dysfunctional.Besides,FC between Distal ACC and left DLPFC might contribute to clinical outcome predication(p=0.01).It implied that ACC has subregions with different disrupted pattern as regards to cognitive and emotion functions.2.Exploring the relationship between the impairment and the recovery area after antidepressant treatment.Using fractional amplitude of low-frequency fluctuation(f ALFF)as features,we performed multi-voxel pattern analysis over MDD patients at baseline vs HC,and over pretreatment MDD patients vs posttreatment MDD patients.Based on these analyses,discriminative regions in ACC for MDD impairment and changes after antidepressant were obtained.Then,we calculated the intersection set and difference sets of these two discriminative regions,and formed ACC subregions in relation to being recovered,unrecovered and compensative respectively.Among them,the recovered ACC subregion mainly distributed in rostral ACC(80%)and the other two subregions had nearly equally distribution over dorsal ACC and rostral ACC,suggested that the local function of ACC was partly recovered on cognitive function after antidepressant.Statistical analysis shown that only the subregion that was compensative in local information had statistically changed FC with CON after antidepressant treatment.Overall,ACC has subregions with different disrupted patterns as regards to cognitive and emotion functions.Besides,the impairment and the recovery area in ACC after antidepressant treatment had an inconsistent spatial distribution,and its intersection was more distributed in the ventral ACC.