Fig. 2.

EEG NREM delta power. NREM delta power (normalized, % of BL ± SEM) was determined across 20- (ZT4–24) and 4-h (ZT0–4) time blocks on BL (BL), sleep restriction (SD1–SD5), and recovery (R1–R3) days. For the 20-h period, NREM delta power was not calculated on SD1–SD5 because of the minimal amount of NREM sleep time that occurred while animals were in the SD wheels. All significance values represent comparisons to the corresponding 20- or 4-h period of BL (∗, P < 0.05; ∗∗, P < 0.01; ∗∗∗, P < 0.001).