(A) Wheel-running actograms from wild type (WT), Bax KO, Melanopsin KO (MKO), and Bax/Melanopsin double KO (DKO) mice. Only DKO mice were unable to entrain their activity to different light cycles: 12:12 hour light:dark (LD), constant darkness (DD), constant light (LL), and ultradian cycle (3.5:3.5 hour light:dark). The gray background denotes when lights were off. (B) DKO mice were unable to confine their activity to the dark portion of the 12:12 LD cycle in (A), as indicated by no significant difference from 50% (t-test, * indicates p<0.05). (C) DKO mice did not lengthen their period under constant light (paired t-test, * indicates p<0.05). (D) A 15-minute light pulse at CT16 (circles in b) generated a similar phase shift in all groups of mice (no significant difference by one-way ANOVA with Tukey post hoc). For all graphs Mean±SEM.