Differential association of default mode network connectivity and rumination in healthy individuals and remitted MDD patients.

Rumination is associated with increased default-mode network (DMN) activity and functional connectivity (FC) in depressed and healthy individuals. In this study, we sought to examine the relationship between self-reported rumination and resting-state FC in the DMN and cognitive control networks in 25 remitted depressed patients and 25 matched healthy controls using independent component and seed-based analyses. We also explored potential group differences in the global pattern of resting-state FC. Healthy subjects with increased levels of rumination exhibited increased anterior DMN connectivity with the posterior DMN and the dorsal attention network and low connectivity within the anterior DMN. On the other hand, remitted depressed ruminators patients were associated with the opposite FC pattern in these regions. Based on global FC patterns, a support vector machine algorithm correctly classified 92% of the subjects into their respective group by a leave-one-out cross-validation. Whole-brain FC analysis also revealed a group by rumination interaction effect within the DMN. The present findings highlight the different functional roles of the anterior and the posterior DMN, and provide novel insights into the underlying neural mechanisms leading to depression relapse.