Exposure to an enriched environment increases the survival of newborn neurons in DG-NR1KO mice. A, Experimental timeline. B, Representative images showing BrdU+ (green) and Prox1+ (red) cells in the dentate gyrus of adult control and DG-NR1KO mice with or without exposure to the enriched environment. Scale bar: 60 μm. C, Density of BrdU+ cells in the dentate gyrus of adult control and DG-NR1KO mice with or without exposure to the enriched environment. D, Proportion of BrdU+ cells expressing Prox1. E, Density of BrdU+/Prox1+ cells in the granule cell layer of adult control and DG-NR1KO mice with or without exposure to the enriched environment. F, Normalized density of BrdU+/Prox1+ cells in the granule cell layer of adult control and DG-NR1KO mice with or without exposure to the enriched environment. Density of each mouse was divided by a mean value of mice without exposure to the enriched environment in the same genotype; *p < 0.05, ***p < 0.005, Tukey’s HSD test (performed because of significant genotype × housing interaction in two-way ANOVA); ###p < 0.005, the main effect of genotype or housing (without significant interaction).