Laying out the evidence for the persistence of neurogenesis in the adult human hippocampus.

[First paragraph] We read with great interest the recent review article by Isabel Maurus et al. [1], which succinctly summarizes the main beneficial effects of aerobic exercise on negative and cognitive symptoms in schizophrenia and the key neurobiological mechanisms that may underpin these effects. The authors rightly highlight, among other mechanisms, the upregulation of brain-derived neurotrophic factor (BDNF) together with structural changes associated with aerobic exercise. Neurogenesis is a key aspect of structural plasticity and a wealth of experimental knowledge has accumulated on the robust neurogenesis-inducing effects of physical activity in rodents. Moreover, decreased cell proliferation in the dentate gyrus was found in schizophrenia, thereby providing strong, but not conclusive, evidence that reduced neurogenesis forms part of the underlying disease process in the brain [2]. We therefore think that, in their review, the authors may have been overly cautious in their discussion of the generation of new neurons in the adult hippocampus. This is likely due to a recent report that has cast doubt on the persistence of neurogenesis in the adult human dentate gyrus [3]. Considering the wide readership of The European Archives of Psychiatry and Clinical Neuroscience among students, clinical academics, and researchers, this letter is intended to provide, in brief form, some perspective on this important debate.