Insomnia and emotional dysfunction: Altered brain network connectivity across sleep and wakefulness states

Abstract

Objective: To investigate the relationship between insomnia-induced sleep disturbance and emotional dysfunction and whether the brain network functional connectivity patterns during either wakefulness or sleep states functioned as a mediator in this relationship.

Methods: Twenty participants with non-clinical insomnia disorder (ID) and 20 normal controls (NC) were recruited and underwent resting-state Electroencephalography (EEG) recordings during wakefulness and sleep stages. Functional connectivity was analyzed using coherence (COH) across multiple frequency bands. The relationships between COH metrics and self-reported emotional measures and the potential mediation effects were investigated.

Results: The ID group revealed sleep stage-specific alterations in brain network functional connectivity, with enhanced alpha connectivity being observed in non-rapid eye movement (NREM) sleep and increased delta connectivity in both phasic and tonic rapid eye movement (REM) sleep stages. Increased alpha band connectivity in anterior-posterior networks during wakefulness was associated with emotional regulation difficulties and depressive symptoms. Mediation analyses showed that alpha and delta band connectivity between frontal-occipital regions mediated the relationship between insomnia and emotional dysregulation.

Conclusions: These findings reveal the pattern of functional connectivity is differently changed in insomnia disorder across wakefulness and sleep states, and such connectivities play a mediation rolein relationship between chronic sleep disruption and emotional regulation in insomnia disorder. These findings provide a novel insight into the neurophysiological mechanisms linking sleep disruption to emotional dysfunction and suggest these aberrant functional connectivity patterns as potential neurophysiological targets for insomnia intervention.

Keywords: Coherence (COH); Emotional dysregulation; Functional connectivity; Insomnia disorder; Phasic REM; Tonic REM.