next story

You know that amazing feeling you get from a full night's sleep? I mean, there really is no other word to describe it. I got eight hours' sleep the other night—all in a row!—and the next day, it was like I was in a commercial for mattresses or something! I practically bounced out of bed.

University of Wisconsin researchers performed a sleep study on mice in which they found that the that the production rate of the myelin-making cells doubled as mice snoozed. The biggest increase was noticed during REM, the kind of sleep that is associated with dreaming. Obviously, the research was done on mice and not humans. But the researchers still think the results suggest that humans may work similarly. Says study author Dr. Chiara Cirelli: "Now it is clear that the way other supporting cells in the nervous system operate also changes significantly depending on whether the animal is asleep or awake."