Figure 4

Rhythm properties of neonatal SCN in culture from the control, Dec1/Dec2 deficient, Cry1/Cry2 deficient, and Cry1/Cry2/ Dec1/Dec2 quadruple-KO mice. (A) Mean periods of PER2::LUC rhythms with standard deviations (SD) calculated by periodogram are shown as columns and vertical lines. A number in each column indicates the number of SCN examined. (B) Standardized amplitude of PER2::LUC rhythms are expressed in bar graph (mean ± SD). (C) Damping ratio of PER2::LUC rhythms is also shown in a bar graph (mean ± SD). Statistical comparisons, a; P < 0.05, aa; P < 0.01 vs. control, b; P < 0.05, bb; P < 0.01 vs. Dec1/Dec2 deficient mice, c; P < 0.05 vs. Cry1/Cry2 deficient mice (one-way ANOVA with a post hock Tukey–Kramer test or Kruskal–Wallis with a post-hoc Steel-test). (D) Peak phase of PER2::LUC rhythms on the 1st day of culture in ZT is illustrated as Rayleigh plot, where ZT 0 indicates the time of light-on in the light–dark cycles. Blue dots indicate the peak phases of individual rhythms. Red arrow in each circle indicates the mean circadian phase of each genotype. A red circle is 95% confidence level. If an arrow extends over the red circle, the distribution of peak phases is regarded as significantly consolidated. Data of the control and Cry1/Cry2-deficient SCN are same as in Fig. 3.