Structural alterations in a rumination-related network in patients with major depressive disorder

Abstract

AbstractRumination is a common symptom in major depressive disorder (MDD) and has been linked to risk for that disorder, its prognosis, and relapse likelihood. Previous work has linked individual differences in rumination to structural properties in a variety of brain regions. Some of these regions, such as the dorsolateral prefrontal cortex (dlPFC), have also been highlighted as being altered in MDD, suggesting a connection between structural changes and ruminative symptoms. Although informative, such localised relations have some limitations in the context of a network view of the brain. To further investigate rumination-related structural changes in depression and to situate these within potential functional networks, we acquired structural data from patients with MDD (n = 32) and controls (n = 69). Analysis of cortical grey-matter identified group differences in the dlPFC that were, however, not related to rumination. Instead, rumination was correlated with grey-matter properties in the right precuneus. Using normative functional connectivity analysis on a large independent sample, we show that these two regions are interconnected. It was further shown that the rumination-related precuneus region is highly connected with networks associated with processes such as executive function, autobiographical memory, and visual perception. Notably, each of these processes has been connected to rumination. These results suggest that rumination in depression may be linked to focal structural changes that disrupt a distributed functional network.