The Impact Of Cognitive Behavioral Therapy On Functional Connectivity In Patients With First-episode Depression

Major depressive disorder(MDD)is a common mental illness with high prevalence and high recurrence rate that seriously damage human mental health.The specific mechanism of its pathogenesis is still in the exploratory stage.Clinically,Cognitive behavior therapy(CBT)can effectively improve the cognitive level of patients with depression and reduce the symptoms of the disease,but the underlying neural mechanism is still unclear.To explored the neurological mechanisms of MDD and the extent to which CBT treatment can treat depression.Sixty-two patients with untreated depression and 23 healthy controls were enrolled in the study.Six-week CBT treatment was an intervention method,with hippocampus,left and right hippocampus,and different brain regions in the limbic system as regions of interest.Resting magnetic resonance imaging was performed before and after treatment to analyze brain functional connectivity data before and after treatment.Method of functional connectivity:(1)Functional connectivity between hippocampus and the whole brain.The two groups were subjected to two-sample t-test before and after treatment in the depression group.(2)Functional connectivity between left and right hippocampus and the whole brain.The two groups were subjected to two-sample t-test before and after treatment in the depression group.(3)Functional connectivity between different brain regions in the limbic system.The two groups were subjected to paired sample t test before and after treatment in the depression group.The research results are as follows:Before treatment,Compared with the healthy controls,MDD group showed significantly increased functional connectivity(FC)between hippocampus and right middle frontal gyrus,right angular gyrus,decreased FC between hippocampus and bilateral putamen,right insula,left superior temporal gyrus.After treatment,from pre-to post-treament,MDD group showed significantly increased FC between hippocampus and left Calcarine,decreased FC between hippocampus and bilateral middle cingulate cortex,bilateral precuneus(p<0.01,FWE corrected).Before treatment,Compared with the healthy controls,MDD group showed significantly increased FC between left hippocampus and right middle frontal gyrus,bilateral inferior parietal gyrus,right angular gyrus,decreased FC between left hippocampus and bilateral putamen,right insula.After treatment,from pre-to post-treament,MDD group showed significantly increased FC between left hippocampus and left Calcarine,right postcentral cortex,decreased FC between left hippocampus and bilateral middle cingulate cortex(p<0.01,FWE corrected).Before treatment,Compared with the healthy controls,MDD group showed significantly increased FC between right hippocampus and right middle frontal gyrus,decreased FC between right hippocampus and right putamen,right insula.After treatment,from pre-to post-treament,MDD group showed significantly increased FC between right hippocampus and left Calcarine,decreased FC between right hippocampus and bilateral middle cingulate cortex,right precuneus,left inferior parietal gyrus(p<0.01,FWE corrected).There were functional connectivity between the brain regions of different structures and functions in the limbic system.Before and after treatment.there was only a statistically significant difference in the functional connectivity between the left and right hippocampus and the left post cingulate cortex in the MDD group(p<0.001)..CBT treatment is applied to the cognitive control level of MDD patients.Emotion regulation brain regions inhibit negative emotion.reprocessing of MDD group after treatment.The left hippocampus has more functional connectivity with cognitive control-related brain regions,and the functional connections between the left and right hippocampus and the whole brain are laterally different.The functional connectivity value between the hippocampus and the right hippocampus and the right frontal middle gyrus can predict the severity of the MDD patients.Before and after treatment.there was only a statistically significant difference in the functional connectivity between the left and right hippocampus and the left post cingulate cortex in the MDD group.The 6-week short-course CBT treatment inhibited the processing of negative emotions in some brain regions and reduced the patient's disease symptoms,but did not achieve a clinical cure.