Preserved temporal hierarchy but frequency-specific alterations in dynamical regimes of EEG microstate multimers during reversible unconsciousness.
NeuroImage February 4, 2026 Chun-Yan Wang, Dong-Dong Zhou
EEG microstate sequences, which reflect brief patterns of brain activity, show precise temporal rhythms across theta, alpha, beta, and gamma frequency bands. These rhythms persist during both wakefulness and reversible unconsciousness induced by anesthesia or deep sleep. The periodic patterns arise from repeating multimer structures and the duration of each microstate, as shown by surrogate data analysis and a generative model. During deep sedation and N3 sleep, beta-band microstates specifically increase in peak power and shift to a lower center frequency. A new algorithm extracted these multimer sequences, revealing distinct frequency-dependent changes during unconsciousness that point to a shift toward specific dynamical brain regimes. The findings offer potential neurophysiological biomarkers for assessing consciousness.