ABSTRACT
Interest in adult neurogenesis increased tremendously in the 1980s after F. Nottebohm demonstrated seasonally regulated neurogenesis in the song nuclei of songbirds and provided evidence that adult neurogenesis subserved a neural function. Spurred in part by the dramatic findings in avian species, interest in adult neurogenesis in mammals increased precipitously into the 1990s, with several laboratories publishing seminal investigations of the nature and extent of neurogenesis in the adult mammalian brain. Quantitatively, the extent of adult neurogenesis in the hippocampus is only a fraction of that in the anterior portion of the adult subventricular zone, a thin, persistent remnant of the secondary proliferative zone of the developing brain. Evidence that neurogenesis is sustained in the senescent brain, albeit at a lower level than in young adults, was provided among early studies of adult neurogenesis using thymidine labeling and electron microscopy. There have been several attempts to link changes in neurogenesis and aging-related deficits in hippocampal-dependent functions.
