FIGURE 7.

Qualitative analysis of the ultrasonic vocalizations (USVs) emitted during the social interaction test in old mice. Ultrasonic calls were automatically classified in the categories described in detail in Figure 2 (A–H). The “complex tot” category (I) contained all complex calls with more than 3 components. Data are expressed as mean ± SEM. *p < 0.05 from the 2 × 2 ANOVA at old age with genotype and stress as the between subject factors, leading to a significant main effect of stress (B,I). N for each group are indicated as (N) in each graph.