When you go to sleep tonight, your brain may be busy making memories of what you did today — and it will do it in quick spurts, as if your day was being replayed in fast-forward.University of Arizona researchers report that the brain’s medial prefrontal cortex appears to replay daytime activities during sleep six to seven times faster than real time.
Somehow that sounds right — almost as if I can perceive that’s what’s happening when I (eventually) go to sleep.











