Fig. 2.
The dynamic connectivity analysis method. (A) Representative time plot of suppression ratio (SR), (B) frontal-parietal and prefrontal-frontal connectograms, and (C) time course of connectivity states from cluster analysis. The connectivity patterns (i.e., frontal-parietal and prefrontal-frontal weighted phase lag index [wPLI]) from all non–burst suppression windows were subjected to principal component analysis for dimensionality reduction and then classified into eight clusters (blue circles) via k-means clustering, while the windows with burst suppression were partitioned into an additional cluster “BS” (gray circles). The black vertical lines indicate the start of propofol infusion, the start and end of isoflurane exposure from left to right, and the red vertical lines indicate the time of loss of consciousness and recovery of consciousness, respectively.