Brain Networks Connectivity in Mild to Moderate Depression: Resting State fMRI Study with Implications to Nonpharmacological Treatment

Abstract

Network mechanisms of depression development and especially of improvement from nonpharmacological treatment remain understudied. The current study is aimed at examining brain networks functional connectivity in depressed patients and its dynamics in nonpharmacological treatment. Resting state fMRI data of 21 healthy adults and 51 patients with mild or moderate depression were analyzed with spatial independent component analysis; then, correlations between time series of the components were calculated and compared between-group (study 1). Baseline and repeated-measure data of 14 treated (psychotherapy or fMRI neurofeedback) and 15 untreated depressed participants were similarly analyzed and correlated with changes in depression scores (study 2). Aside from diverse findings, studies 1 and 2 both revealed changes in within-default mode network (DMN) and DMN to executive control network (ECN) connections. Connectivity in one pair, initially lower in depression, decreased in no treatment group and was inversely correlated with Montgomery-Asberg depression score change in treatment group. Weak baseline connectivity in this pair also predicted improvement on Montgomery-Asberg scale in both treatment and no treatment groups. Coupling of another pair, initially stronger in depression, increased in therapy though was unrelated to improvement. The results demonstrate possible role of within-DMN and DMN-ECN functional connectivity in depression treatment and suggest that neural mechanisms of nonpharmacological treatment action may be unrelated to normalization of initially disrupted connectivity.

Altered effective connectivity in sensorimotor cortices is a signature of severity and clinical course in depression

“…At the same significance level, the χ 2 analyses failed to show significant differences between two groups in terms of sex ratio and mild/moderate depression ratio. It is noteworthy that here data from a subset of participants from the present study have been published (46,109,110). However, those works mainly employed a data-driven approach based on independent component analysis decomposition of the whole-brain data and correlation-based (undirected) functional connectivity analysis unlike the current study that tests a specific hypothesis by investigating (directed) effective connectivity in functionally characterized brain regions.…”

Objective biomarkers of depression: A study of Granger causality and wavelet coherence in resting‐state fMRI

“…The participant selection as well as the image acquisition were performed by Bezmaternykh et al. and the methods are presented in detail in their study 25 . The study involves 51 medication‐free patients with a diagnosis of mild depressive episode, moderate depressive episode, or dysthymia according to the International Classification of Diseases 10th Revision, as established in the multiprofile clinic Pretor and International Institute of Psychology and Psychotherapy, Novosibirsk, Russia.…”

“…There is no significant difference between the two groups in terms of gender, age, and intelligence level (Raven's Progressive Matrices test). All subjects signed informed consent to participate in the experiment 25 . Demographic and clinical characteristics of the groups involved in the study are presented in Table 1.…”

Alteration of whole-brain amplitude of low-frequency fluctuation and degree centrality in patients with mild to moderate depression: A resting-state functional magnetic resonance imaging study

“…Acceptable translation and rotation range <3 mm or 3°rotation. After excluding 2 cases that did not meet the diagnosis criteria of mild to moderate depression, 49 patients in the mild to moderate depression group and 21 healthy control group were finally enrolled [details of the open database can be found here 2 ( 17 ) ( 18 )].…”