State-specific thalamic dysregulation in chronic insomnia revealed by dynamic edge-centric functional connectivity

To investigate dynamic cortical-thalamocortical-subcortical network dysregulation in chronic insomnia (CI) using dynamic edge functional connectivity (deFC) analysis, focusing on thalamus-mediated transient connectivity states and their clinical correlations. 30 CI patients and 32 matched healthy controls (HCs) underwent resting-state fMRI. We calculated deFC with the thalamus as a hub node, identified transient connectivity states via K-means clustering, and compared inter-group differences. Clinical assessments included the Pittsburgh sleep quality index (PSQI), self-rating anxiety scale (SAS), and self-rating depression scale. Temporal attributes of dynamic functional networks showed no significant differences between the CI and HC groups. All participants appeared across all four states, confirming state stability. number of transitions, fraction time and nean dwell time were comparable between groups, with no significant differences observed in any state (all p > 0.05). Four dynamic brain states showed distinct patterns of abnormal edge functional connectivity (eFC) between the CI and HC groups. Significant abnormalities in eFC between the CI and HC groups were identified across four brain states (p < 0.0001, FDR-corrected). Dominance of the right thalamus was observed in states 1 and 3, while dominance of the left thalamus was predominant in states 2 and 4. Correlation analyses revealed that specific abnormal eFCs involving thalamocortical and subcortical regions were significantly associated with clinical scale scores of the PSQI and SAS within the CI group. This study offers a temporal network perspective on insomnia-related neural changes and reveals state-specific alterations in thalamic-mediated eFC in CI, marked by hemispheric asymmetry.