Time course of sleep (upper panels) and NREMS EEG delta power (lower panel). Data from baseline (BSL), sleep deprivation (SD), and recovery (REC) are shown. Open (Cry1,2-/-) and closed (Cry1,2+/+) symbols designate mean hourly values ± 1 SEM. In the lower panel, thicker lines connect mean predicted delta power values based on the sleep-wake distribution in individual mice; (see Methods). Triangles mark intervals in which recovery values differed from corresponding baseline values within each genotype (triangle orientation designates direction of deviation; P < 0.05, post-hoc paired t-tests). Gray bars at the bottom of each panel mark intervals with significant genotype differences (P < 0.05, post-hoc t-tests). The baseline dark period was depicted twice to illustrate the changes at the dark-to-light transition.