Activity-Dependent Regulation of the Early Phase of Adult Hippocampal Neurogenesis

Abstract

New neurons are generated from neural stem cells through the neuronal progenitor cell stage at the dentate gyrus of the hippocampal formation throughout life, and contribute to higher cognitive function, such as learning and memory. Physiological conditions, such as voluntary exercise or enriched environment, or pathophysiological conditions, such as stroke or epilepsy, upregulate the generation of new neurons, but the mechanism for governing the promotion of adult neurogenesis has not been fully clarified. It has been widely accepted that the neural activities of the hippocampal circuitry regulate the generation of hippocampal new neurons. Actually, a number of neurotransmitter systems – serotoninergic, GABAergic, cholinergic, purinergic, and glutamatergic systems – are involved in the regulation of adult hippocampal neurogenesis process. In this chapter, we propose a possible involvement of activity-dependent regulation of the fate of neural stem/progenitor cells in enhanced hippocampal neurogenesis. In a series of studies, we and others have reported how hippocampal activity affects the generation of new neurons, even at the early phase of adult hippocampal neurogenesis. These findings may also contribute to the pharmaceutical enhancement of adult neurogenesis for treating neurodegenerative and psychological disorders.