Body weight and behavioral analyses of mice across ages 2 to 9 months. A, B, Body weight in KO and control mice (males, A; females, B). C, D, Changes in spontaneous explorative activity across ages. Ambulatory distance (gross horizontal locomotion) during 10 min in males (C) and in females (D). E, F, Rearing time in males (E) and in females (F). Values are expressed as mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001 (RM-ANOVA followed by LSD post hoc test).