The default mode network and rumination in individuals at-risk for depression.

Abstract

The default mode network (DMN) is a network of brain regions active during rest and self-referential thinking. Individuals with Major Depressive Disorder (MDD) show increased or decreased DMN activity, relative to controls. DMN activity has been linked to a tendency to ruminate in MDD. It is unclear if individuals who are at-risk for, but who have no current or past history of depression, also show differential DMN activity associated with rumination. We investigated whether females with high levels of neuroticism with no current or lifetime mood or anxiety disorders (n=25) show increased DMN activation, specifically when processing negative self-referential information, compared with females with average levels of neuroticism (n=28). Participants heard criticism and praise during functional MRI scans in a 3T Siemens Prisma scanner. The at-risk group showed greater activation in two DMN regions, the medial prefrontal cortex (MPFC) and the inferior parietal lobule (IPL), after hearing criticism, but not praise (relative to females with average levels of neuroticism). Criticism-specific activation in the IPL was significantly correlated with rumination. Individuals at-risk for depression therefore may have an underlying neurocognitive vulnerability to use a brain network typically involved in thinking about oneself to preferentially ruminate about negative, rather than positive, information.