Copyright © 2015 Korean Neuropsychiatric Association 227 ORIGINAL ARTICLE Increased Cognition Connectivity Network in Major Depression Disorder: A fMRI Study

ObjectiveaaEvidence of the brain network involved in cognitive dysfunction has been inconsistent for major depressive disorder (MDD), especially during early stage of MDD. This study seeks to examine abnormal cognition connectivity network (CCN) in MDD within the whole brain. MethodsaaSixteen patients with MDD and 16 health controls were scanned during resting-state using 3.0 T functional magnetic reso-nance imaging (fMRI). All patients were first episode without any history of antidepressant treatment. Both the left and right dorsolater-al prefrontal cortex (DLPFC) were used as individual seeds to identify CCN by the seed-target correlation analysis. Two sample t test was used to calculate between-group differences in CCN using fisher z-transformed correlation maps. ResultsaaThe CCN was constructed by bilateral seed DLPFC in two groups separately. Depressed subjects exhibited significantly in-creased functional connectivity (FC) by left DLPFC in one cluster, overlapping middle frontal gyrus, BA7, BA43, precuneus, BA6, BA40, superior temporal gyrus, BA22, inferior parietal lobule, precentral gyrus, BA4 and cingulate gyrus in left cerebrum. Health controls did not show any cluster with significantly greater FC compared to depressed subjects in left DLPFC network. There was no significant dif-ference of FC in right DLPFC network between depressed subjects and the health controls. ConclusionaaThere are differences in CCN during early stage of MDD, as identified by increased FCs among part of frontal gyrus, pa