Figure 5. Home-cage locomotor activity.

Rats were tested in home-cage activity monitors for 48 h, starting 8 h before the start of the dark cycle and continuing through 2 dark cycles, one full light cycle and two partial light cycles, one at the beginning and one at the end. The vivarium was on a 14 h light, 10 h dark cycle. A, activity starting on P35. B, activity starting on P50. At both ages KO rats were hyperactive when first placed in the test. As both groups habituated, the higher activity of KO rats disappeared. Six hours into the first dark cycle, hyperactivity in KO rats reemerged and remained during most of the dark phase. At P35 KO hyperactivity continued during the second light phase then disappeared as habituation continued, reemerging a second time 6 h into the second dark phase, slowly dissipating during the last light phase. At P50 the dark cycle hyperactivity in the KO rats disappeared earlier than at P35, becoming non-significant during the last 4 h of the dark cycle. At this age there was a brief spike in activity in the KO rats 6 h into the light cycle, then disappeared again. During the second dark cycle, hyperactivity reappeared again 6 h into the dark phase. At this age the KO hyperactivity disappeared as soon as the last light cycle began. Data are Mean ± SEM. Since there was no genotype x sex interaction, sexes are shown combined. Group sizes: P35: Male: WT n = 19, KO n = 19 Female: WT n= 19, KO= 19; P50: Male: WT n = 19, KO n = 19 Female: WT n= 19, KO= 19. Male: WT n=19, KO n=20; female: WT n=20, KO n=20. *p ≤ 0.05; **p ≤ 0.01, ***p < 0.001 vs. WT.