Creativity. The rest is silence Humming with activity...

It appears that the right brain, the creative part gets active when one is physically at rest and awake. Interestingly left handed people may have more of this activity, because in them the right brain is more dominant.

<a href="https://news.yahoo.com/youre-rest-brains-side-hums-221352993.html" target="_blank" rel="nofollow noopener noreferrer">When You're At Rest, Your Brain's Right Side Hums</a>