It used to be thought that neurogenesis ceased soon after birth. Recently,though, neural stem cells (NSCs) have been isolated from most parts of the adult nervous system, suggesting that it retains a widespread potential for neurogenesis. Klein et al. now describe how NSCs derived from mouse cerebellum and forebrain possess intrinsic regional characteristics (see p. 4497). The researchers first use an in vitro neurosphere assay to show that multipotent progenitor cells exist in embryonic and adult cerebellum. They then show that NSCs isolated from cerebellum and forebrain give rise to progeny that are characteristic of the brain area from which they originate, both in vitro and after transplantation back into the brain region from which they came. By contrast, NSCs from both regions largely fail to make neurons when transplanted ectopically. Thus, although NSCs bestow regional characteristics on their progeny, proper neurogenesis also requires regional environmental cues.