If you have been practicing a piece of music, hearing it again while you are sleeping could help you play it more accurately the next time, according to a study from Northwestern University published online in June in Nature Neuroscience.

Sixteen participants with a range of musical education learned to play two melodies by pressing keys in time with a sequence of moving circles, as in the video game Guitar Hero. During a 90-minute nap, one of the tunes was played over and over during slow-wave sleep, which is thought to be an important period for memory consolidation. When the participants awoke, they were better at both tunes, but their accuracy was especially improved for the tune they had heard (without knowing it) in their sleep.

“Memory processing during sleep happens, and it can be beneficial,” says senior author Ken A. Paller. “The findings we have suggest that slow-wave sleep is a very important part of the process.” Future research will focus on the memory mechanisms at work during this stage of the sleep cycle—and their practical implications.