Source-resolved electroencephalogram microstates reveal opposing prefrontal-posterior dynamics and a candidate temporal-to-precuneus pathway in disorders of consciousness

Abstract

Objective and circuit-level biomarkers of consciousness are urgently needed for disorders of consciousness. We recorded high-density electroencephalography from 33 patients with disorders of consciousness (17 vegetative state/unresponsive wakefulness syndrome, 16 minimally conscious state) and 19 healthy controls during rest and auditory stimulation, and combined source-localized microstate analysis with hypothesis-generating Granger causality analysis. Source microstate 3 (right prefrontal) and microstate 4 (parieto-occipital-temporal) showed diametrically opposite dynamics: microstate 3 was enhanced in the vegetative state whereas microstate 4 coverage and occurrence were higher in the minimally conscious state, revealing a fronto-posterior opponent imbalance. In repeated internal cross-validation within this cohort, microstate 4 occurrence discriminated the two patient groups (area under the curve = 0.812, 95% confidence interval 0.647–0.945). Hypothesis-generating connectivity analysis nominally implicated stronger right middle temporal-to-precuneus information flow in the minimally conscious state, a signal that did not survive network-level multiplicity correction. Source-resolved microstates thus reveal opposing cortical dynamics associated with consciousness level.