Alpha activity during REM sleep contributes to overnight improvement in performance on a visual discrimination task

The purpose of this preliminary study was to clarify the association between cortical and subcortical activities during REM and non-REM sleep with overnight improvement of performance on a procedural memory task. Eleven healthy volunteers (M age = 23.8 yr., SD = 3.1) participated in this study which was conducted over two consecutive nights: an adaptation night and the experimental night. They underwent a visual discrimination task before and after the experimental night. A positive correlation was observed between overnight performance improvement on the visual discrimination task and EEG alpha band power during REM sleep, while no significant correlation was observed between the performance and either the amount of Stage REM sleep, REM activity, or other sleep variables. The findings corroborate other studies and suggest that cortical activity during REM sleep contributed to procedural memory consolidation and highlights the importance of measuring quantitative REM sleep components to elucidate the role of physiological sleep on memory consolidation in humans.