Dysfunction of the cingulo-opercular network in first-episode medication-naive patients with major depressive disorder

Background: Major depressive disorder (MDD) is a common psychiatric disorder that may be associated with abnormal cognitive control and emotion regulation. Previous studies have found that network disconnection within the cingulo-opercular network (CON) plays an important role in psychiatric disorders and that the CON may be relevant to the psychopathology of MDD. We thus used the resting-state functional connectivity method in patients with MDD and healthy controls to examine CON neural circuit abnormalities in MDD. Methods: Using resting-state functional magnetic resonance imaging (fMRI), we investigated the resting state functional connectivity of the CON using the dorsal anterior cingulate cortex (dACC) as the seed region of interest. The resulting functional connectivity (FC) correlation maps were employed to investigate between-group differences. Additionally, we examined the association between depression symptom severity and functional connectivity results. The participants were patients with MDD (n=19) and healthy controls (n=19). Results: Patients with MDD showed abnormalities in the connectivity of the CON. We found abnormal connectivity in MDD patients between the dACC and the bilateral middle frontal gyrus (MFG) and left angular gyms (LAG) and precentral gyrus. Moreover, regression analysis showed that depression symptom severity (measured with the Hamilton Depression Rating Scale (HDRS), Hamilton Anxiety Rating Scale (HARS) and Automatic Thoughts Questionnaire scores (ATQ)) was significantly correlated with the FC values of the CON. Limitations: First, our study consisted of a relatively small sample size that may have limited statistical power. Second, the current study design cannot conclusively specify the role of the CON in the neuropathology of depression. Conclusions: Our findings suggest that MDD is associated with disrupted FC of the CON, which plays an important role in the pathophysiological mechanisms of MDD. (C) 2016 Elsevier B.V. All rights reserved.