Brain microstate spatio-temporal dynamics as a candidate endotype of consciousness

Area of Science:

• Neuroscience
• Clinical Neurophysiology

Background:

• Consciousness is a continuously evolving phenomenological experience.
• Conscious mental activity involves discrete spatiotemporal patterns of global neuronal firing.

Purpose of the Study:

• To identify novel endotypes of consciousness in severe acquired brain injury (sABI) patients using EEG microstate analysis.
• To investigate associations between microstate features and neurophysiological alterations.
• To analyze the prognostic value of microstate dynamics in patients with prolonged disorder of consciousness (pDoC).

Main Methods:

• Utilized high-temporal-resolution EEG recordings in sABI patients admitted to an Intensive Rehabilitation Unit (IRU).
• Applied microstate analysis to investigate spatiotemporal brain dynamics.
• Examined microstate features, transitions, and sequence complexity in relation to neurophysiological alterations and patient outcomes.

Main Results:

• Frontally-oriented microstates (C microstate), their stability, transitions, and complexity indicate consciousness presence and levels.
• Left-right asymmetric microstates correlate negatively with antero-posterior brain reorganization and EEG symmetry.
• Microstate complexity and C topography differ significantly across patient groups with varying EEG backgrounds (alpha dominant, cortical reactivity, antero-posterior gradient).
• Transitioning from left-right to antero-posterior microstates independently predicts consciousness recovery, outperforming initial consciousness level assessments.

Conclusions:

• Global brain dynamics, measured by scale-free estimators, serve as indicators of consciousness presence.
• These dynamics are candidate markers for short-term recovery prediction in patients with pDoC.