Figure 2.

The variability of stimulus-induced activity across trials (trial-to-trial variability, TTV) during the peak period (4–5s) in wakefulness, propofol-induced sedation and deep anesthesia. Group-level z-maps (one sample t-tests against zero) were corrected at alpha<0.05 at the cluster level. A. Results without global signal regression (No-GSR). B. Results with GSR. Note that these significant TTV changes are negative values (namely reduction), because of the normalization against the stimulus onset (see Methods); it thus indicates how the TTV changes relative to the baseline.