What happens in our brains while we’re asleep? That’s one question neuroscientist Penelope Lewis is trying to answer. She directs the Sleep and Memory Lab at the University of Manchester in England. Her new book is The Secret World of Sleep: The Surprising Science of the Mind at Rest.

https://www.npr.org/2013/08/15/212276021/of-neurons-and-memories-inside-the-secret-world-of-sleep