Complex sound processing during human REM sleep by recovering information from long-term memory as revealed by the mismatch negativity (MMN)

Perceptual learning is thought to be the result of neural changes that take place over a period of several hours or days, allowing information to be t ransferred to long-term memory. Evidence suggests that contents of long-ter m memory may improve attentive and pre-attentive sensory processing. Theref ore, it is plausible to hypothesize that learning-induced neural changes th at develop during wakefulness could improve automatic information processin g during human REM sleep. The MMN, an objective measure of the automatic ch ange detection in auditory cortex, was used to evaluate long-term learning effects on pre-attentive processing during wakefulness and REM sleep. When subjects learned to discriminate two complex auditory patterns in wakefulne ss. an increase in the MMN was obtained in both wake and REM states. The au tomatic detection of the infrequent complex auditory pattern may therefore be improved in both brain stares by reactivating information from long-term memory. These findings suggest that long-term learning-related neural chan ges are accessible during REM sleep as well. (C) 2001 Elsevier science B.V. All rights reserved.