(A) Quantification of BrdU-positive cells in OBs of young (3- to 4-month-old) and old (16- to 18-month-old) mice of different genotypes. Data are mean ± SEM. (B) Quantification of NEUN-positive cells over total newly formed cells, and a representative photograph of EdU/NEUN colabeling 1 month after EdU injection in aged Wip1-Tg mice. Arrowheads indicate examples of EdU-positive nuclei that colocalize with NEUN. A arrow indicates an EdU-positive, NEUN-negative cell. Data are mean ± SEM. (C) Quantification of the proportion of calretinin-positive newborn neurons (calretinin+EdU⁺ cells) over total EdU-positive cells (EdU⁺ cells), and a representative photograph of EdU/calretinin colabeling 1 month after EdU injection in aged Wip1-Tg mice. Data are mean ± SEM. (D) Representative image of EdU/NESTIN colabeling from aged Wip1-Tg mice and quantification of LR-BrdU–positive cells per SVZ section in WT, Wip1-Tg, p16^Ink4a KO, and Wip1-Tg /p16^Ink4a KO mice. Additional analysis of EdU-labeled cells is provided in Supplemental Figure 3, F and G. Data are mean ± SEM. (E) Quantification of short-term incorporation of BrdU, a proliferation marker of NPCs. Data are mean ± SEM. (F) Quantification of DCX-positive cells in young and aged WT and Wip1-Tg SVZs. Representative photographs of DCX staining in the SVZ areas of young and aged WT and aged Wip1-Tg mice, and quantification of DCX-positive area in the SVZ. Data are mean ± SD. *P < 0.05; ***P < 0.005. Scale bar: 40 μm (B); 30 μm (C); 20 μm (D); 200 μm (F).