Altered Electroencephalographic Resting-State Large-Scale Brain Network Dynamics in Euthymic Bipolar Disorder Patients.

Alena Damborská,Alexandre G Dayer,Christoph M Michel,Cristina Berchio,Camille Piguet,Jean-Michel Aubry

doi:10.3389/fpsyt.2019.00826

Abstract

Background: Neuroimaging studies provided evidence for disrupted resting-state functional brain network activity in bipolar disorder (BD). Electroencephalographic (EEG) studies found altered temporal characteristics of functional EEG microstates during depressive episode within different affective disorders. Here we investigated whether euthymic patients with BD show deviant resting-state large-scale brain network dynamics as reflected by altered temporal characteristics of EEG microstates.Methods: We used high-density EEG to explore between-group differences in duration, coverage, and occurrence of the resting-state functional EEG microstates in 17 euthymic adults with BD in on-medication state and 17 age- and gender-matched healthy controls. Two types of anxiety, state and trait, were assessed separately with scores ranging from 20 to 80.Results: Microstate analysis revealed five microstates (A–E) in global clustering across all subjects. In patients compared to controls, we found increased occurrence and coverage of microstate A that did not significantly correlate with anxiety scores.Conclusion: Our results provide neurophysiological evidence for altered large-scale brain network dynamics in BD patients and suggest the increased presence of A microstate to be an electrophysiological trait characteristic of BD.

Highlights

Bipolar disorder (BD) is a common and severe psychiatric disorder, with an important personal and societal burden [1, 2]
Regions implicated in the pathophysiology of the disease, such as the inferior frontal gyrus, the medial prefrontal cortex, and the amygdala present altered activation patterns even in unaffected first-degree relatives of BD patients [10], pointing toward brain alterations that could underlie disease vulnerability
Evidence from functional magnetic resonance imaging studies showed aberrant restingstate functional connectivity between frontal and meso-limbic areas in BD when compared to healthy controls [11]

Summary

Introduction

Bipolar disorder (BD) is a common and severe psychiatric disorder, with an important personal and societal burden [1, 2]. Regions implicated in the pathophysiology of the disease, such as the inferior frontal gyrus, the medial prefrontal cortex (mPFC), and the amygdala present altered activation patterns even in unaffected first-degree relatives of BD patients [10], pointing toward brain alterations that could underlie disease vulnerability. Different fMRI metrics allowed to report deviant patterns of large-scale networks and altered resting-state functional connectivity [14, 15] in BD, the precise temporal dynamics of the functional brain networks at rest remain to be determined. Neuroimaging studies provided evidence for disrupted resting-state functional brain network activity in bipolar disorder (BD). We investigated whether euthymic patients with BD show deviant resting-state large-scale brain network dynamics as reflected by altered temporal characteristics of EEG microstates

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