Figure 6.

The timing of developmental neurogenesis and astrogenesis by hippocampal subregion. (A) Heatmap diagrams summarizing the developmental timing of neurogenesis (blue) and astrogenesis (purple) in the CA1, CA3 and dentate gyrus of the mouse hippocampus. Neurogenesis and astrogenesis occur sequentially and are largely nonoverlapping in the CA1 and CA3 regions. In contrast, neurogenesis and astrogenesis occur simultaneously in the dentate gyrus, and at the same time that dentate gyrus neural stem cells (NSCs) transition into quiescence (red). NSC transition to quiescence data are from Berg et al., 2019. (B) Heatmap diagrams summarizing the developmental timing of neurogenesis (blue) and astrogenesis (purple) in subregions of the CA1, CA3 and dentate gyrus, as well as the NSC transition to quiescence in the subgranular zone of the dentate gyrus (red). Colors correspond to the same legend in (A). Neurogenesis in the CA1 and CA3 regions dominates during embryonic development. Neurogenesis in the dentate gyrus and astrogenesis throughout the hippocampal regions occurs during early postnatal development, but the timing of peak astrogenesis varies by subregion. In addition, dentate gyrus NSCs in the subgranular zone transition into quiescence during early postnatal development. Finally, most cytogenesis in the hippocampus has ceased by P14, except for low levels of neurogenesis and astrogenesis in the dentate gyrus, which continues throughout adulthood.