Mutual interaction between visual homeostatic plasticity and sleep in adult humans

International audienceSleep and plasticity are highly interrelated, as sleep slow oscillations and sleep spindles are associated with consolidation of Hebbian-based processes. However, in adult humans, visual cortical plasticity is mainly sustained by homeostatic mechanisms, for which the role of sleep is still largely unknown. Here, we demonstrate that non-REM sleep stabilizes homeostatic plasticity of ocular dominance induced in adult humans by short-term monocular deprivation: the counterintuitive and otherwise transient boost of the deprived eye was preserved at the morning awakening (>6 hr after deprivation). Subjects exhibiting a stronger boost of the deprived eye after sleep had increased sleep spindle density in frontopolar electrodes, suggesting the involvement of distributed processes. Crucially, the individual susceptibility to visual homeostatic plasticity soon after deprivation correlated with the changes in sleep slow oscillations and spindle power in occipital sites, consistent with a modulation in early occipital visual cortex. Editor's evaluation Menicucci and colleagues investigated the potential role of sleep in the homeostatic plasticity of ocular dominance in adult humans. This is a careful study that should be of broad interest to those studying adult cortical plasticity, particularly in vision. The study shows that sleep can maintain the changes in ocular dominance obtained after applying an eye patch on the dominant eye for two hours, which contrasts with the rapid decline of these changes during quiet wake in darkness. The authors further report correlations between sleep oscillations and the magnitude of the plasticity effect. Overall, these results implicate sleep in a new form of plasticity