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

Dmitry D. Bezmaternykh,Kira A. Natarova,Mark B. Shtark,Mikhail Ye. Melnikov,Evgeniy D. Petrovskiy,Lyudmila I. Kozlova,Andrey A. Savelov,Bingjin Li

doi:10.1155/2021/8846097

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.

Highlights

Depression is a widespread psychiatric disorder associated with a number of different symptoms
Depression is mostly associated with increased functional connectivity (FC) within default mode network (DMN) [1,2,3,4,5,6,7,8,9] with a few contradicting findings [1, 10,11,12,13]
Collected data support crucial role of within-DMN and DMN-executive control network (ECN) FC in depression and demonstrate need for a further study of the relationships between these networks coupling and development and treatment of depression for using a relatively big sample of depressed patients we found decrease of within-DMN FC that contradicts typical findings in the field

Summary

Introduction

Depression is a widespread psychiatric disorder associated with a number of different symptoms. Depression is mostly associated with increased functional connectivity (FC) within DMN [1,2,3,4,5,6,7,8,9] with a few contradicting findings [1, 10,11,12,13]. External FC of the DMN is increased to anterior cingulate [1, 14,15], thalamus [14], and pars triangularis [3] and decreased to fusiform gyrus, motor cortices [16], cerebellum, insula [17], thalamus, putamen, and calcarine sulcus [18] with mixed findings for hippocampus [1, 18,19]. Depression is associated with less coupling of DMN and anterior salience network (ASN) [2]

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