FIG. 4.
Locomotor activity rhythms in casein kinase mutant mice. (A) Mean period length. (B) Rhythm amplitude. Rhythm parameters were determined for two consecutive 21-day epochs in constant darkness (DD) for wild-type control mice (WT; n = 27), CK1δΔ2/+ mice, (n = 21), and CK1e−/− mice (n = 9). Asterisks indicate a significant effect of genotype within each period of study (P < 0.01, Dunnett's test). The rhythm amplitude did not differ between the genotypes (P > 0.05). (C and D) Phase-shifting responses to 1-h light pulses were similar among CK1δΔ2/+ mice, CK1e−/− mice, and wild-type control mice. Values are the mean ± the standard error of the mean (SEM) of 2 to 12 (average of 6) pulses per bin per genotype.