Figure 4. Timed voluntary wheel activity reveals an endogenous circadian activity rhythm in Per1/2/3 triple mutant mice.

Representative double-plotted actograms of general activity of Per1/2/3 triple mutant mice recorded by passive infrared motion detectors in constant darkness with ad libitum chow and a locked running wheel. Actograms are plotted with either a 21-h period (A) or 24-h period (B). The wheel was unlocked for 1 h each cycle on a 21-h interval (Wheel: T = 21 h) and then released into constant conditions (continuously locked wheel). Then the wheel was unlocked for 1 h each cycle on a 24-h cycle (Wheel: T = 24 h) and then released into constant conditions. All individual actograms of general activity and wheel revolutions are shown in Supplementary Fig. S11. Male: #30 and 68. Female: #26 and 35.