Researchers from Northwestern University noted that stimulation during sleep could reinforce what people have already learned, but doesn’t help them gain new skills.
Their research has shown that memory is strengthened for something you’ve already learned rather than learning something new in your sleep, we’re talking about enhancing an existing memory by reactivating information recently learned.
In the study, researchers taught participants how to play two musical tunes by pressing certain keys at certain times then after they learned how to play the tunes, the participants took a 90-minute nap. While they slept, only one of the songs, with soft musical cues was played during slow-wave sleep, a stage of sleep that is linked to storing memories.
As the participants napped, the researchers recorded their electrical brain activity. After they woke up, the participants made fewer mistakes when playing the tune that was played while they were sleeping than the one that was not played.
The results showed that external stimulation during sleep can influence a complex skill.
Electrophysiological signals were found during sleep and only correlated with the extent to which memory improved and these signals may be measuring the brain events that produce memory improvement during sleep.
The researchers said they are investigating how their findings could be applied to other types of learning, such as studying a foreign language. Their research could also lead to more studies on sleep-based memory-processing involving other types of skills, habits and behaviors.