Affordable Access

deepdyve-link
Publisher Website

Tracking brain states under general anesthesia by using global coherence analysis.

Authors
  • Cimenser, Aylin1
  • Purdon, Patrick L
  • Pierce, Eric T
  • Walsh, John L
  • Salazar-Gomez, Andres F
  • Harrell, Priscilla G
  • Tavares-Stoeckel, Casie
  • Habeeb, Kathleen
  • Brown, Emery N
  • 1 Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA. [email protected]
Type
Published Article
Journal
Proceedings of the National Academy of Sciences
Publisher
Proceedings of the National Academy of Sciences
Publication Date
May 24, 2011
Volume
108
Issue
21
Pages
8832–8837
Identifiers
DOI: 10.1073/pnas.1017041108
PMID: 21555565
Source
Medline
License
Unknown

Abstract

Time and frequency domain analyses of scalp EEG recordings are widely used to track changes in brain states under general anesthesia. Although these analyses have suggested that different spatial patterns are associated with changes in the state of general anesthesia, the extent to which these patterns are spatially coordinated has not been systematically characterized. Global coherence, the ratio of the largest eigenvalue to the sum of the eigenvalues of the cross-spectral matrix at a given frequency and time, has been used to analyze the spatiotemporal dynamics of multivariate time-series. Using 64-lead EEG recorded from human subjects receiving computer-controlled infusions of the anesthetic propofol, we used surface Laplacian referencing combined with spectral and global coherence analyses to track the spatiotemporal dynamics of the brain's anesthetic state. During unconsciousness the spectrograms in the frontal leads showed increasing α (8-12 Hz) and δ power (0-4 Hz) and in the occipital leads δ power greater than α power. The global coherence detected strong coordinated α activity in the occipital leads in the awake state that shifted to the frontal leads during unconsciousness. It revealed a lack of coordinated δ activity during both the awake and unconscious states. Although strong frontal power during general anesthesia-induced unconsciousness--termed anteriorization--is well known, its possible association with strong α range global coherence suggests highly coordinated spatial activity. Our findings suggest that combined spectral and global coherence analyses may offer a new approach to tracking brain states under general anesthesia.

Report this publication

Statistics

Seen <100 times