Increased Global and Regional Connectivity in Propofol-induced Unconsciousness: Human Intracranial Electroencephalography Study.

Summary

Using intracranial EEG from 73 patients, propofol-induced unconsciousness showed increased global and regional functional connectivity with reduced complexity and efficiency, alongside delta increase and high-gamma suppression. Posterior connectivity best discriminated conscious vs. unconscious states.

Key Findings

• Global functional connectivity increased across all frequency bands under propofol-induced unconsciousness, while global complexity and efficiency decreased.
• Power spectral changes included increased delta and decreased high-gamma power.
• Posterior connectivity most strongly contributed to machine-learning classification of conscious vs. unconscious states; amplitude-based increases dominated in delta/theta and phase-based increases from beta to high-gamma.

Clinical Implications

Highlights posterior network connectivity and reduced network efficiency as candidate EEG markers for depth of anesthesia and consciousness monitoring.

Limitations

• Patient cohort consists of individuals with epilepsy undergoing intracranial monitoring, limiting generalizability
• Observational design; causal inferences regarding mechanisms are indirect

Future Directions

Prospective validation in non-epileptic cohorts, integration with anesthesia depth monitors, and interventional tests targeting posterior networks.