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Recording Brain Electromagnetic Activity During the Administration of the Gaseous Anesthetic Agents Xenon and Nitrous Oxide in Healthy Volunteers
Published on: January 13, 2018
Phase-based measures of cross-frequency coupling in brain electrical dynamics under general anesthesia
Eran A Mukamel1, Kin Foon Wong, Michael J Prerau
1Swartz Program for Theoretical Neuroscience, Harvard University, Cambridge, MA 02138, USA.eran@post.harvard.edu
Summary
General anesthesia (GA) alters brain waves, but traditional analysis misses cross-frequency coupling. New methods reveal distinct patterns of brain activity linked to anesthetic-induced unconsciousness, improving monitoring.
Area of Science:
- Neuroscience
- Anesthesiology
- Signal Processing
Background:
- General anesthesia (GA) increases power in slow oscillation (SO) and alpha (α) EEG bands.
- Conventional spectral analysis is limited in exploring cross-frequency coupling (CFC) under GA.
- Understanding CFC is crucial for monitoring anesthesia and the neuroscience of unconsciousness.
Purpose of the Study:
- To evaluate two CFC measures: SynchFastSlow and modulogram analysis.
- To determine if CFC patterns can differentiate states of consciousness under propofol GA.
- To assess the utility of CFC for improving depth-of-anesthesia monitoring.
Main Methods:
- Calculated SynchFastSlow (bispectrum-derived) and modulogram (SO phase-α amplitude coupling).
- Correlated SynchFastSlow with loss of consciousness during propofol GA induction.
- Analyzed CFC patterns in waking and two GA states using a 2D phase space.
Main Results:
- SynchFastSlow correlated with GA but was influenced by power changes.
- Modulogram analysis identified two distinct CFC modes under GA.
- A stereotyped phase-amplitude coupling pattern was observed across anesthetic-induced unconsciousness stages.
Conclusions:
- Modulogram analysis offers insights into brain states under GA beyond conventional methods.
- Phase-amplitude coupling patterns are characteristic of anesthetic-induced unconsciousness.
- CFC analysis, particularly modulograms, can enhance EEG-based brain state monitoring during anesthesia.
