Summary: The resting brain repeatedly and rapidly replays faster memories of what a person has recently learned and practiced. The more a person replays the memory during rest, the better they become during subsequent sessions where they practice their newly learned skill.

Source: NIH

In a study of healthy volunteers, National Institutes of Health researchers have mapped out the brain activity that flows when we learn a new skill, such as playing a new song on the piano, and discovered why taking short breaks from practice is a key to learning.