Locomotor activity and anxiety-like behavior in the open field (OF) and elevated plus maze (EPM).

<p>(A) Anxiety-like behavior was measured by the ratio of center distance to total distance in the OF. The ratio did not detect significant differences between ad libitum (AL) and caloric-restricted (CR) fed mice (AL: n_{4w, 20w, 74w} = 10, 10, 8; CR: n_{4w, 20w, 74w} = 9, 10, 10). However, 74 weeks (74w) vs. 4 weeks (4w) CR fed mice revealed a decreased ratio indicating a raised level of anxiety-like behaviour (F_2,26 = 6.551, P = 0.005). Values are given as mean±SEM; ANOVA, post-hoc pairwise comparison tests: ^*P<0.05 vs. 74w. (B) The defecation rate in OF, a parameter of anxiety-like behavior, was significantly higher in all ad libitum (AL) fed mice when compared to age-related caloric-restricted (CR) fed mice (4 weeks: F_1,17 = 4.729, P = 0.044; 20 weeks: F_1,18 = 9.175, P = 0.007; 74 weeks: F_1,16 = 5.854, P = 0.028. Values are given as mean ± SEM; ANOVA, post-hoc pairwise comparison tests: ^§P<0.05 vs. AL. (C) The ratio of open arms visits to total visits as a parameter of anxiety-like behavior was significantly increased only in 4 weeks CR fed mice when compared to age-matched AL fed mice (F_1,16 = 6.115, P = 0.025) and significantly decreased upon lifelong CR (F_2,24 = 10,713, P<0.001). Values are given as mean±SEM; ANOVA, post-hoc pairwise comparison tests: ^§P<0.05 vs. AL, ^$P<0.05 vs. 4w.