Time-dependent involvement of adult-born dentate granule cells in behavior

Adult-born neurons are continuously generated and incorporated into the circuitry of the hippocampus throughout life in mammals. Cumulative evidence supports a physiological role for adult-born neurons, yet it not clear whether this subset of dentate granule cells makes a unique contribution to hippocampal function. Perturbation or ablation of adult hippocampal neurogenesis leads to deficits in the acquisition of learned associations or memory recall, whereas an increase in adult hippocampal neurogenesis enhances some forms of learning and memory. The observed effects thus far appear to be task-dependent, species-specific, and sensitive to the timing of manipulations. Here, we review the recent evidence correlating adult-born dentate granule cells (DGCs) with hippocampal-dependent behavior and focus on the dynamic properties of this neuronal population that may underlie its function. We further discuss a framework for future investigations of how newly integrated neurons may contribute to hippocampal processing using advanced genetic techniques with enhanced temporal resolution.

► Adult neurogenesis continues throughout life but its physiological role is still uncertain.
► Contribution of newborn neurons to behavior is regulated by dynamic intracellular environment.
► Increased temporal resolution is required to assess role of adult-born cells in learned behavior.
► Determining process of functional integration can inform research of stem cell therapeutics.