Fig. 2.
Total power alterations under xenon and nitrous oxide anesthesia relative to postantiemetic baseline in various frequency bands. Baseline and gas power (A) at each concentration is averaged across all samples for all subjects (MEG, n = 21; EEG, n = 19) and considering all voxels of the magnetoencephalogram (MEG) and electroencephalogram (EEG). Units of power for MEG (A) are T2 and for EEG (B) are μV2. The figure demonstrates changes in all frequency bands that are different for the two modalities, and in some cases, correlate to increasing gas concentration. Error bars illustrate ±1 SD. Relative change (B) ([(Gas or Baseline Power − Postantiemetic Baseline Power) / Postantiemetic Baseline power] × 100) is calculated and all changes are shown with each sub-figure in bold percentage values. Delta, 1 to 4 Hz; theta, 4 to 8 Hz; alpha, 8 to 13 Hz; beta, 13 to 30 Hz; low gamma, 30 to 49 Hz; high gamma, 51 to 99 Hz.