Sleep deprivation suppresses adult neurogenesis: Clues to the role of sleep in brain plasticity

Abstract

Sleep is hypothesized to play a critical role in facilitating brain growth and plasticity. Neurogenesis in the adult hippocampus is a recently established model of brain plasticity. We determined how adult neurogenesis was affected by sleep deprivation (SD) using an intermittent treadmill deprivation system, which permits comparisons with movement-matched controls. Immunohistochemistry for bromodeoxyuridine (BrdU) and neuron-specific nuclear antigen (NeuN) was used to quantify the proliferative and neurogenic processes. Following 96 h SD, proliferation of new cells was reduced by 50%. Three weeks following the termination of SD, the proportion of BrdU-labeled cells exhibiting a mature neuronal phenotype was reduced by 35%. Combining the suppression of proliferation and failure in development of mature neuronal phenotype, we estimate that 96 h SD reduced new dentate gyrus neurons generated during the deprivation period by 60%. Suppression of proliferation was not associated with elevation of the stress hormone corticosterone. Current evidence suggests that the detrimental effects of SD on neurogenesis requires accumulated sleep debt and is not quickly reversible. We speculate that the suppression of neurogenesis by SD is associated with suppression of protein synthesis.