Representative actograms with Hal treatment periods indicated by colored bars (left); bar graphs indicate corresponding locomotor period (right). (A) Increasing concentrations of Hal provided in the drinking water gradually shortens the endogenous ultradian activity rhythms of Bmal1−/− mice in DD (B, mean ± SEM, N = 12; F2,10 = 14.36, p < 0.0001, repeated measures ANOVA; *p < 0.05 and **p < 0.01, planned comparison ANOVA). (C and E) Hal shortens the infradian rhythms in Meth-treated Bmal1−/− mice (D, mean ± SEM, N = 9; F1,8 = 2.357, *p < 0.05 ANOVA) and WT mice (F, mean ± SEM, N = 9; F1,8 = 3.525, **p < 0.01, ANOVA) in DD. (G) Hal treatment increases the frequency of temperature fluctuation in Slc6a3−/− mice under LD measured by telemetric implants. (H) Changes of amplitude spectral density in the ultradian range (2–8 hr) in response to increasing Hal concentrations (mean ± SEM; N = 8; F2,7 = 14.74, repeated measures ANOVA, *p < 0.05, ***p < 0.0005, post-hoc Bonferroni). For all experiments, periods are calculated based on the running wheel activity during the last 7 days of treatment at the indicated Meth/Hal concentration.