Fig. 1

Hippocampal neurogenic niche produces new neurons through a cascade of different cell types. Neural stem cells (NSCs) provide a basal level influx of new amplifying neuroprogenitors (ANPs) through asymmetric divisions. Newborn ANPs divide several times but only some of them survive to differentiate into the early neuroblast (NB). As these cells continue to differentiate into immature neurons (IN), their numbers are reduced further. In the end, only a few mature neurons, so called granule cells (GC), are produced. Throughout the neurogenic cascade, the different cell types undergo apoptosis (Apop). The apoptotic cells live for a short period of time because they are rapidly phagocytosed and degraded by the resident microglia