Figure 1.

The dynamics of proliferation and differentiation in the adult neurogenic niches. Neural stem cells (NSCs) divide, both symmetrically and asymmetrically for self-renewal and production of transit amplifying cells (TACs). The term neuroprogenitors encompasses TACs and true NSCs. TACs rapidly divide symmetrically to amplify the availability of neural and glial precursors and finally differentiate into one of the three neural lineages: neuronal (N), astroglial (A), or oligodendroglial (O).