Brains Sweep Themselves Clean Of Toxins During Sleep --- While the brain sleeps, it clears out harmful toxins, a process that may reduce the risk of Alzheimer's, researchers say. --- During sleep, the flow of cerebrospinal fluid in the brain increases dramatically, washing away harmful waste proteins that build up between brain cells during waking hours, a study of mice found. --- "It's like a dishwasher," says Dr. Maiken Nedergaard, a professor of neurosurgery at the University of Rochester and an author of the study in Science. - NPR