Information Integration and Mesoscopic Cortical Connectivity during Propofol Anesthesia

Area of Science:

• Neuroscience
• Anesthesiology
• Computational Neuroscience

Background:

• Propofol-induced loss of consciousness mechanisms are well-studied at macro and micro scales.
• Mesoscopic changes in cortical connectivity and information integration during propofol anesthesia remain less understood.

Purpose of the Study:

• To investigate changes in information integration and cortical network connectivity at the mesoscopic (cortical) scale during propofol-induced unconsciousness.
• To analyze how electrocorticogram (ECoG) cross-electrode coupling varies with distance and brain region under propofol anesthesia.

Main Methods:

• Analysis of ECoG data from 9 surgical patients undergoing propofol anesthesia.
• Utilized genuine permutation cross mutual information to assess ECoG cross-electrode coupling.
• Employed network metrics (clustering coefficient, path length, nodal efficiency) to evaluate cortical network changes at nodal and global levels.

Main Results:

• Genuine permutation cross mutual information and genuine connections decreased with increasing electrode distance (up to ~3 cm) in all cortical regions.
• Nodal network metrics (clustering coefficient, nodal efficiency) decreased from wakefulness to unconsciousness.
• Global network metrics (average clustering coefficient, average path length) showed a slight increase in the early unconscious state.

Conclusions:

• Genuine permutation cross mutual information effectively captures propofol-induced coupling changes at the cortical scale.
• Loss of consciousness involves a shift in information integration, characterized by reduced global transmission capacity and increased local functional segregation.