The Effect On Functional Connectivity Of Brain Network Of Cognitive Behavior Therapy For First-episode Treatment-naive Mild To Moderate Patients With Major Depressive Disorder

Objective:Major depressive disorder(MDD) is a very common severe mental disorder, and the mechanism of MDD is unknown.Cognitive behavior therapy can be used as a treatment of mild-to-moderate MDD,but the brain network effects of CBT for MDD is still unknown.For these reason,first-episode treatment-naive adult patients with MDD were used as subjects to explore alterations of brain network of patients before and after 6 weeks of treatment with CBT.The study examined the differences in functional connectivity of brain network between MDD patients and healthy controls, and investigated the neutral mechanism of MDD and CBT by using resting state functional magnetic resonance imaging(rs-fMRI).Methods:Eighteen patients with first-episode treatment-naive depressed patients and twenty matched healthy controls were recruited and underwent the first rs-fMRI sanning. Afterward, the patients received 6 weeks of treatment. The treatments were carried out by experienced therapist according to treatment manual. The patients who completed 6 weeks of treatment were scaned agian. Seed-based functional connectivity analysis was used to define the congitive control network(CCN), and a region to region connectivity and a region to whole brain analysis were performed to explore the functional connectivity within the CCN and between subgenual anterior cingulate cortex(sgACC) and whole brain using the profressional software, and two sample t-test was used to compared the z-score between patients and controls.Results:CCN includes bilateral middle fontal gyrus、bilateral inferior frontal-gyrus, dorsal anterior cingulate cortex, left middle cingulate cortex and bilateral inferior parietal gyrus.Before treatment,compared with healthy controls, depressed patients showed signaficantly decreased functional connectivity between right middle frontal gyrus and right inferior frontal gyrus, and signaficantly decreased functional connectivity between sgACC and the left superior frontal gyrus, left middle frontal gyrus and left angular gyrus.After treatment, Compared with healthy controls,depressed patients still showed signaficantly decreased functional connectivity between right middle frontal gyrus and right inferior frontal gyrus, and decreased functional connectivity between sgACC and bilateral superior frontal gyrus, left medial frontal gyrus, right precuneus and left angular gurus, and increased sgACC connectivity to right inferior frontal gyrus, right cerebellum.From pro- to post-treatment, patients exhibited decrease functional connectivity between dorsal anterior cinglate cortex and left middle cingulate cortex, and increased functinal connectivity between sgACC and bilateral inferior frontal gyrus, bilateral middle temporal gyrus, left inferior temporal gurus, right supramarginal gyrus, left precentral cortex and right cerebellum.Conclusion:The result suggests that abnormality functional connectivity with CCN may be existed in depressed patients during resting state. The alteration of CCN may be related to the psychopathology of depression, specifically may related to the biased attention.The early stage of CBT can not modulate the CCN, but may directly modulate functional connectivity between sgACC and some nodes of CCN and default mode network, which result in enhancing response inhibition and reducing self-referential process and rumination of MDD patients.