Cognitive enhancing effects of voluntary exercise, caloric restriction and environmental enrichment: a role for adult hippocampal neurogenesis and pattern separation?

•Physical exercise, dietary restriction, and enriched environments are associated with improved cognition and increased adult hippocampal neurogenesis.•Increased adult hippocampal neurogenesis is associated with improved pattern separation on memory tasks.•Recent evidence suggests that improved pattern separation may underlie the cognitive improvements from physical exercise and dietary restriction.

Several behavioural interventions, such as physical exercise, dietary restriction, and enriched environments are associated with both improved cognition and increased adult hippocampal neurogenesis. Whether the learning and memory improvements associated with these interventions are causally dependent on the upregulated neurogenesis has not yet been conclusively determined. However, with the accumulating evidence of a role for adult-born hippocampal neurons in spatial pattern separation, it is possible that the improvements in learning and memory result, at least in part, from an improvement in pattern separation. The following review focuses on three major behavioural manipulations associated with cognitive enhancement: voluntary exercise, caloric restriction, and environmental enrichment (including learning), and how increased neurogenesis may contribute to the enhancement by improving pattern separation.