Fig. 3. Normalized power spectral density calculated using the average of all primary somatosensory cortex (SI) (A ) and ventroposterolateral thalamic nuclei (VPL). (B ) Local field potentials (LFP) channels illustrating the changes in spectral power across awake (before induction [BI]), isoflurane anesthetic concentrations (0.8, 1.1, 1.4, and 1.7), and after recovery (AR). (C ) SI-VPL LFP coherence measurements illustrating a stronger level of coherence of simultaneously recorded channels of LFPs across the frequency bands considered at the different study periods BI, isoflurane concentrations (0.8, 1.1, 1.4, and 1.7%), and AR. Frequency bands: Δ  (1–4 Hz), θ (4–9 Hz), α (9–15 Hz), β (15–30 Hz), γ-low (30–50 Hz), and γ-high (50–100 Hz). Values are means ± SE. Comparisons based on two-way analysis of variance test, followed by Bonferroni post hoc  test. *P < 0.05; **P < 0.01, and ***P < 0.001. Color version of this figure is available at www.anesthesiology.org.