Figure 3.

Mean number of male USV when confronted with a female per day on 10 consecutive days and after an interval of 30 days (between day 10 and day 40) in WT (n = 6) and Period1-deficient (Per1^−/−; n = 16) mice. Compared with the maximal call number at day 2, a significant reduction was observed at day 4 in WT (#) and at day 6 in Per1^−/− (§) male mice. After the 30-day interval of no contact to female mice, the call number in the Per1^−/− male mice was significantly elevated ($), whereas this was not the case in the WT mice. Data were analysed by ANOVA with Bonferroni post-test (#/§ denotes p ≤ 0.05; $ denotes p ≤ 0.01). All values are given as mean ± s.e.m.