Figure 4. Main effects of genotype on circadian behavioral characteristics in 12L:12D (a–c) and constant darkness (d–f).

a | The percent of wheel-running activity in the light-phase is significantly increased in Pet-1 ^−/− mice. b | Pet-1 ^−/− mice exhibit a significant increase in length of daily wheel-running duration (alpha) in LD for Pet-1 ^−/− mice. c | Rhythmic power is significantly decreased in Pet-1 ^−/− mice. d | Free-running period of Pet-1 ^−/− mice is significantly decreased in DD. As in LD, Pet-1 ^−/− mice in DD exhibit (e) a greater duration of daily activity and (f) reduced rhythmic power. Error bars represent SEM; asterisks (*) denote significance at p ≤0.05.