Figure 3. Effect of sex and age on the expression of PER2::Luc in the retina. The endogenous period, amplitude, phase, and rhythmic power are calculated at 3 days baseline in retinal explants from A: 2-month-old male and female Per2^Luc mice and B: male and female Per2^Luc mice divided into four groups and aged 1 month, 2–3 months, 4–5 months, or 6–8 months. Bars represent mean ± SEM n = 12 for each group, except 1 month: n = 8. Statistical differences are indicated by *: p<0.05 or **: p<0.01.