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

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.

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.

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.

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.