Sleep and Plasticity

Abstract

From a neurocentric view, sleep's active role in plastic processes is widely accepted as a key function of sleep. During wakefulness, acquisition of new information through learning and environmental interactions activates Hebbian plasticity mechanisms that induce local, plastic changes in the brain, leading to an overall increase in the net synaptic strength, which is accompanied by cell stress and may lead to learning saturation. Subsequent sleep episodes promote global, non-Hebbian downscaling processes that promote synaptic renormalization and reestablish neuronal selectivity and learning capacity. Concurrently, offline memory consolidation processes during sleep underpin a comprehensive resampling of mnemonic traces and allow an internal dialogue between brain structures, thereby facilitating memory stabilization and integration in the knowledge network. The exact mechanisms underlying these plastic processes during sleep are being discussed.