Nap Time Can Reinforce Recently Acquired MemoriesNew research suggests that memory can be strengthened by listening to recently learned information while taking a nap.

The findings are especially appropriate for musicians, as Northwestern University researchers say a way to really learn a new tune is to take a nap with the recently learned melody playing during your sleep.

The research grows out of recent evidence that suggests memories can be reactivated during sleep and storage of them can be strengthened in the process.

In the Northwestern study, research participants learned how to play two artificially generated musical tunes with well-timed key presses. Then while the participants took a 90-minute nap, the researchers presented one of the tunes that had been practiced, but not the other.

“Our results extend prior research by showing that external stimulation during sleep can influence a complex skill,” said Ken A. Paller, Ph.D., senior author of the study.

By using EEG methods to record the brain’s electrical activity, the researchers ensured that the soft musical “cues” were presented during slow-wave sleep, a stage of sleep previously linked to cementing memories.

Participants made fewer errors when pressing the keys to produce the melody that had been presented while they slept, compared to the melody not presented.

“We also found that electrophysiological signals during sleep correlated with the extent to which memory improved,” said lead author James Antony of the Interdepartmental Neuroscience Program at Northwestern.

“These signals may thus be measuring the brain events that produce memory improvement during sleep.”

Researchers say the findings do not imply that you can learn totally new material while you sleep, rather, newly learned material can be reinforced.

So, despite the hype, you cannot learn a foreign language while you sleep, said Paul J. Reber, Ph.D., associate professor of psychology at Northwestern and a co-author of the study.

“The critical difference is that our research shows that memory is strengthened for something you’ve already learned,” Reber said. “Rather than learning something new in your sleep, we’re talking about enhancing an existing memory by reactivating information recently acquired.”

The researchers, he said, are now thinking about how their findings could apply to many other types of learning.

“If you were learning how to speak in a foreign language during the day, for example, and then tried to reactivate those memories during sleep, perhaps you might enhance your learning.”

Paller said he hopes the study will help them learn more about the basic brain mechanisms that transpire during sleep to help preserve memory storage.

“These same mechanisms may not only allow an abundance of memories to be maintained throughout a lifetime, but they may also allow memory storage to be enriched through the generation of novel connections among memories,” he said.

Researchers say study findings can lead to a wealth of new studies using sleep-based memory processing for many different types of motor skills, habits and behavioral dispositions.

Source: Northwestern University

Young person napping photo by shutterstock.