If you aren't able to master a tune even after hours of practicing, then perhaps you should sleep on it. We mean try sleeping while the tune is being played in the background. A new study has demonstrated how sleep improves the ability to learn a new tune.

"Our results extend prior research by showing that external stimulation during sleep can influence a complex skill," said senior author of the study, Ken A. Paller, professor of psychology, Weinberg College of Arts and Sciences at Northwestern.

For the study, participants were asked to learn two new tunes with well-timed key presses. Then the participants took a nap for about 90 minutes. While they slept, the research team played one of the tunes.

The research team found that, participants were able to play the tunes with the same key-presses when it was played during sleep. Brain activity in the participants was recorded using EEG methods.

"We also found that electrophysiological signals during sleep correlated with the extent to which memory improved. These signals may thus be measuring the brain events that produce memory improvement during sleep." said lead author James Antony of the Interdepartmental Neuroscience Program at Northwestern.

Many studies have shown how sleeping affects recall of information. Complex motor skills can be learned by getting naps while taking breaks during tasks gets better results says a 2010 study that was published in Neuron.

Another study has shown that brief amount of sleep after learning preserves memories that at times last for years.

"The critical difference is that our research shows 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 re-activating information recently acquired," Reber said.

"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," Reber said.

We don't remember everything we learn. One of the tasks of our brain is to filter out what is important and what is not.

"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," Paller said.