A Functional Role for Adult Hippocampal Neurogenesis in Spatial Pattern Separation

TLDR

Adult hippocampal neurogenesis occurs in the dentate gyrus and is thought to influence learning and memory, yet its precise functional contribution remains unclear. The authors ablated neurogenesis in mice and evaluated spatial pattern separation using two behavioral tasks—an arm‑choice sequence and a touchscreen location discrimination. Neurogenesis ablation impaired discrimination only when arms or locations were close, demonstrating its necessity for spatial pattern separation in the dentate gyrus. Citation: Clelland et al.

Abstract

Neurogenesis and Spatial Memory The dentate gyrus of the hippocampus is one of two sites in the brain where new neurons are produced throughout life. Adult-born neurons integrate into the dentate gyrus circuitry and are thought to play a role in learning and memory. However, their contribution to hippocampal function remains unclear. Clelland et al. (p. 210 ) disrupted neurogenesis in mice and used two behavioral tasks to test for impairment in the formation of uncorrelated episodic memory representations. In one task, two arms were presented and the mice were rewarded for choosing the most recently visited arm in an earlier sequence; in the second task, animals were rewarded for choosing a certain location on a touch screen. Ablation of neurogenesis affected discrimination performance in both tasks but only when the arms or screen locations were close to one another. Neurogenesis is thus necessary for spatial pattern separation in the dentate gyrus.