Fig. 4. Indexes derived from the signal recorded on the somatosensory cortex (SI) and in the ventroposterothalamic nuclei (VPL) at different study periods: before induction (BI) of anesthesia at steady-state end-tidal isoflurane concentrations of 0.8, 1.1, 1.4, and 1.7% (0.8, 1.1, 1.4, and 1.7) and after recovery (AR). The following indexes are presented: (A ) approximate entropy (AE), (B ) index of consciousness (IoC), (C ) spectral edge frequency 95% (SEF), (D ) permutation entropy (PE), (E ) burst suppression–corrected SEF (BSSEF), and (F ) burst suppression–corrected PE (BSPE).The mean and SD are presented (n = 5; *P < 0.05).