Biological vulnerability to depression: linked structural and functional brain network findings

Abstract

This is the first evidence of connected structural and functional DMN abnormalities in recovered-state MDD, supporting recent hypotheses on biological-level vulnerability.

Dissociated large-scale functional connectivity networks of the precuneus in medication-naïve first-episode depression

“…Sheline et al (2010) suggested that this widespread aberrant connectivity likely contributed to the diverse symptomatology of MDD. In contrast to findings from treated subjects with MDD ( Sheline et al, 2010;Nixon et al, 2014), we did not find that this region exhibited a significant increase of functional connectivity with the precuneus by the unconstrained whole-brain search in medication-naïve, first-episode MDD. Nevertheless, we observed that in patients with greater severity of depression this region showed hyperconnectivity with the precuneus, highlighting that the dorsal nexus "hot-wiring" might be related to clinical severity, and indicating vulnerability for recurrences in depression.…”

“…DMN hyperconnectivity with the dorsal nexus has also been demonstrated in previously depressed but recovered subjects (Nixon et al, 2014) and first degree relatives of depressed subjects (Norbury et al, 2011), but so far not reported in medication-naïve, firstepisode depression. To our knowledge, only two previous studies have examined DMN connectivity in medication-naïve first-episode subjects.…”

Increased Default Mode Network Connectivity in Individuals at High Familial Risk for Depression

“…Studies examining the resting state with fMRI demonstrate hyperconnectivity within the DMN in patients with MDD (Greicius et al, 2007), dysthymic disorder , and remitted depression (Nixon et al, 2014). Antidepressants reduce DMN hyperconnectivity in depressed patients to levels comparable with healthy control participants , and reductions in prefrontal connectivity correlate with symptom improvement (Wang et al, 2015).…”

577. Lifespan Gyrification Trajectories of Human Brain in Healthy Individuals and Patients with Major Psychiatric Disorders

“…We also found that the gyrification trajectory of patients with MDD might be different from HC, as well as from BD-I and SCZ, but no brain region showed significant alteration of gyrification in MDD. In fact, several studies with small sample size showed higher gyrification in MDD than in healthy controls 57,58 , while some showed lower 18,59 , which could be due to differences in genes or brain connections 57,59 . Further studies will be necessary to clarify these inconsistent results.…”