title: Environmental enrichment and voluntary exercise massively increase neurogenesis in the adult hippocampus via dissociable pathways.
abstract: Environmental enrichment (EE) and voluntary exercise (VEx) have consistently been shown to increase adult hippocampal neurogenesis and improve spatial learning ability. Although it appears that these two manipulations are equivalent in this regard, evidence exists that EE and VEx affect different phases of the neurogenic process in distinct ways. We review the data suggesting that EE increases the likelihood of survival of new cells, whereas VEx increases the level of proliferation of progenitor cells. We then outline the factors that may mediate these relationships. Finally, we provide a model showing that VEx leads to the convergence of key somatic and cerebral factors in the dentate gyrus (DG) to induce cell proliferation. Although insufficient evidence exists to provide a similar model for EE, we suggest that EE-induced cell survival in the DG involves cortical restructuring as a means of promoting survival. We conclude that EE and VEx lead to an increase in overall hippocampal neurogenesis via dissociable pathways, and should therefore, be considered distinct interventions with regard to hippocampal plasticity and associated behaviors.
authors.affiliation: Department of Psychology, Division of Neuroscience and The Brain Research Centre at UBC Hospital, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4. akolsen@psych.ubc.ca
authors.forename: Andrea K
authors.initials: AK
authors.lastname: Olson
authors.forename: Brennan D
authors.initials: BD
authors.lastname: Eadie
authors.forename: Carl
authors.initials: C
authors.lastname: Ernst
authors.forename: Brian R
authors.initials: BR
authors.lastname: Christie
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D002470:Cell Survival / Q000502:physiology; D004779:Environment Design; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D006801:Humans; D009043:Motor Activity / Q000502:physiology*; D009414:Nerve Growth Factors / Q000378:metabolism; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*
chemical_list: D009414:Nerve Growth Factors