Fig. 3.

Variable patterns of food anticipatory activity during daily (24-h) restricted feeding of Per1^−/−/Per2^−/−/Per3^−/− mice in constant darkness. Representative double-plotted actograms (5-min bins) of wheel-running activity of Per1^−/−/Per2^−/−/Per3^−/− mice maintained in constant darkness (indicated by black bars above actograms). Gray shading on left halves of the actograms indicates when food was available. Mice were fed ad libitum for 5 d, then fasted for 48 h to characterize activity during fasting before restricted feeding. Mice were returned to ad libitum feeding for 3 d, then fed 8 h/d for 2 d. In A, the mouse was then fed for 6 h/d for 9 d, whereas in C, the mouse was fed for 6 h/d for 2 d and then 4 h/d for 9 d. On the 10th day of restricted feeding, food was left in the cage, and mice ate ad libitum for 2 d (A) or 4 d (C). Mice were then fasted for 48 h and returned to ad libitum feeding. The χ² periodograms (B and D) correspond to the actograms shown in A and C, respectively. χ² periodogram analysis was performed on days 1–10 of restricted feeding, as indicated on y axes of the actograms. The dotted lines in the periodograms show the significance level P = 0.001. All individual actograms and periodograms (n = 15 in total) are shown in Figs. S5, S6 and S7.