Figure 5.

A reversed light/dark cycle resets behavioral rhythms more slowly than does constant light. A, Actograms of mice after 1, 3, or 5 d of DL cycle. Mice were entrained in LD for 2 weeks. After the last dark period, lights remained off for another 12 h followed by 12 h of light to switch the mice to DL. Mice were in DL for 1, 3, or 5 d before they were placed in DD. Phase shifts are shown as the mean ± SEM. B, A representative actogram after 1 d of reversed LD cycle in the alternative reversal design (DL→LD). C, Immunoblots showing mPER rhythms in liver in DL mice. The second, fifth, and eighth day samples were collected after 1, 4, and 7 d of DL cycle (LD→DL). These samples were compared with control samples (top) collected during LD.