Figure 5: Lineage progression from Hes5∷CreER^T2 NSCs in the adult DG.

Scheme of IP and stem cell-driven homeostatic DG neurogenesis. Type-1 Hes5⁺ NSCs can be quiescent or active. In the current IP driven model, NSCs generate type-2a Ascl1^high IPs through asymmetric cell division. Type-2a IPs undergo symmetric self-replicating progenitor divisions before generating a pool of committed progenitors (type-2b cells also referred to as D1 cells⁵³). These early neuroblasts (Tbr2⁺) undergo a limited number of divisions and give rise to post-mitotic neuroblasts and newborn granule cells. In the stem cell and early neuroblast-driven model, active NSCs divide multiple times, but will generate type-2a Ascl1^high IPs that produce mitotic Tbr2⁺ early neuroblasts (type-2b cells) without amplification of the pool. The type-2b early neuroblasts divide to increase and expand the precursor pool before generating post-mitotic neuroblasts and newborn neurons. The average time taken for these process deduced from the lineage-tracing experiments is shown in days. GCL, granule cell layer, SGZ, subgranular zone.