Adult neurogenesis: a substrate for experience-dependent change.

A rapidly growing body of literature indicates that adult neurogenesis in the hippocampus is sensitive to a variety of environmental factors. The effects of emotionally salient experiences, such as stress and physical exercise, have been characterized extensively with regard to both adult neurogenesis and behaviors associated with the hippocampus. Experience-dependent changes in the production and function of new neurons may serve as a means to fine-tune the hippocampus to the predicted environment. Here, we discuss this possibility along with the argument that more naturalistic experimental conditions may be a necessary step toward understanding the adaptive significance of neurons born in the adult brain.