Ontogeny of adult neural stem cells in the mammalian brain.

Neural stem cells (NSCs) persist into adulthood in the subgranular zone (SGZ) of the dentate gyrus in the hippocampus and in the ventricular-subventricular zone (V-SVZ) of the lateral ventricles, where they generate new neurons and glia cells that contribute to neural plasticity. A better understanding of the developmental process that enables NSCs to persist beyond development will provide insight into factors that determine the size and properties of the adult NSC pool and thus the capacity for life-long neurogenesis in the adult mammalian brain. We review current knowledge regarding the developmental origins of adult NSCs and the developmental process by which embryonic NSCs transition into their adult form. We also discuss potential mechanisms that might regulate proper establishment of the adult NSC pool, and propose future directions of research that will be key to unraveling how NSCs transform to establish the adult NSC pool in the mammalian brain.