Functional implications of hypothalamic neurogenesis in the adult mammalian brain.

Adult neurogenesis represents a striking example of structural plasticity in the mature brain. Research on adult mammalian neurogenesis today focuses almost exclusively on two areas: the subgranular zone (SGZ) in the dentate gyrus of the hippocampus, and the subventricular zone (SVZ) of the lateral ventricles. Numerous studies, however, have also reported adult neurogenesis in the hypothalamus, a brain structure that serves as a central homeostatic regulator of numerous physiological and behavioral functions, such as feeding, metabolism, body temperature, thirst, fatigue, aggression, sleep, circadian rhythms, and sexual behavior. Recent studies on hypothalamic neurogenesis have identified a progenitor population within a dedicated hypothalamic neurogenic zone. Furthermore, adult born hypothalamic neurons appear to play a role in the regulation of metabolism, weight, and energy balance. It remains to be seen what other functional roles adult hypothalamic neurogenesis may play. This review summarizes studies on the identification and characterization of neural stem/progenitor cells in the mammalian hypothalamus, in what contexts these stem/progenitor cells engage in neurogenesis, and potential functions of postnatally generated hypothalamic neurons.