Post date: Jan 4, 2016 2:46:55 PM

SundayReview | OPINION

Goodnight. Sleep Clean.

In a series of new studies, published this fall in the journal Science, sleep, may play a crucial role in our brain’s physiological maintenance. As your body sleeps, your brain is quite actively playing the part of mental janitor: It’s clearing out all of the junk that has accumulated as a result of your daily thinking.