These findings are consistent with those of fMRI studies examining rsFC disturbances in MDD. For example, we observed enhanced phase synchronization between the right SFG and right PHG (regions in the DMN) in the MDD group. These regions overlap with those of a recent fMRI-based meta-analysis, which showed evidence of hyperconnectivity between DMN regions and regions of the hippocampus in those with MDD [4]. The PHG is thought to be the primary node in the medial temporal DMN subsystem that mediates connectivity between DMN regions and structures such as the hippocampus that support autobiographical recall [47]. Connectivity between the PHG and other DMN regions has been found to become enhanced in depressed individuals during recall of negative events [48]. This has also been observed in individuals with rMDD [49], and linked with greater severity of ruminative thoughts, supporting a role for enhanced within-DMN connectivity in rumination. Our observation of enhanced DMN-FPN between-network synchronization in the MDD group, involving the left SFG (DMN) and the right MTG (FPN), also aligns with evidence of enhanced correlation in BOLD signal between the right
