Figure 2.

Neurogenesis is regulated in part by distinct groups of factors. Two discrete steps in dentate gyrus neurogenesis appear to be under separate genetic and biological controls. Proliferation of neural precursor cells is directly regulated by a set of physiological and biological factors, some of which are listed here, whereas survival of newly produced neurons is controlled by a separate group of factors. Several genetic loci and candidate genes that have been suggested by QTL studies to regulate neurogenesis are shown; whether these directly regulate neuronal proliferation or survival is still unclear (as indicated by the question mark). VEGF, vascular endothelial growth factor; BDNF, brain-derived neurotrophic factor.