Figure 3. Light sets the circadian period length, even during adulthood.

(A and B) Representative actograms of wild-type mice raised in either a 12:12-LD cycle (n = 13) or darkness (n = 16), and exposed to 12:12-LD cycle for 1 month. The circadian period of dark-reared mice is lengthened initially, but rescued and is no longer significantly different from 12:12-LD reared mice after light exposure. (C and D) Representative actograms of wild-type mice raised in either a 12:12-LD cycle (n = 17) or in darkness (n = 12), and then exposed to a 3 hr light pulse. Dark-reared mice exhibited a longer period. Following the 3 hr light pulse, the circadian period length of dark-reared animals shortened. (B and D) Two-way ANOVA, Bonferroni's multiple comparisons test and adjusted p values. Error bars represent s.e.m. See also Figure 3—figure supplement 1.

DOI: http://dx.doi.org/10.7554/eLife.22861.008

Figure 3—figure supplement 1. Actograms for all dark reared mice tested.

The lengthened period phenotype exhibited by dark-reared animals was less penetrant than in Opn4^DTA/DTA or P0 enucleated mice. Though a majority of dark-reared animals (9 of 16; 56%;) exhibited a lengthened period, the remainder did not. This is likely due to the process of setting the circadian period being highly sensitive to light.

DOI: http://dx.doi.org/10.7554/eLife.22861.009