Effect of exercise on the hippocampal cell proliferation process. On comparing (A) the number of cells labelled for BrdU in the dentate gyrus of mice SH or exposed to RWs, we found a significant interaction between genotype and exercise. The total number of BrdU-positive cells was decreased in female HD mice when compared with WT animals. Exercise had no effect on HD mice but increased cell proliferation in WT animals. (B) Exercise had no effect on HD mice but significantly increased dentate gyrus volume in WT animals. Values represent means (±SEM) of n = 3–5 mice per group. WT versus HD: *P < 0.05, **P < 0.01, ***P < 0.001; SH versus RW: ##P < 0.01, ###P < 0.001. ns, not significant.