Sleep allows brain to wash out junk
Discovery could lead to better treatments for Alzheimer’s disease
WIDE ASLEEP Colored tracers penetrate more deeply into a mouse’s brain when it’s asleep (left, red tracer) than awake (right, green tracer). The finding indicates that channels between brain cells open up during sleep and allow cerebrospinal fluid to wash debris out of the brain. Blood vessels are shown in blue.
L. Xie, H. Kang and M. Nedergaard
Sleep hoses garbage out of the brain, a study of mice finds.
The trash, including pieces of proteins that cause Alzheimer’s disease, piles up while the rodents are awake. Sleep opens spigots that bathe the brain in fluids and wash away the potentially toxic buildup, researchers report in the Oct. 18 Science.
The discovery may finally reveal why sleep seems mandatory for every animal. It may also shed new light on the causes of neurodegenerative disorders such as Alzheimer’s and Parkinson’s diseases.
“It’s really an eye-opening and intriguing finding,” says Chiara Cirelli, a sleep researcher at the University of Wisconsin–Madison. The results have already led her and other sleep scientists to rethink some of their own findings.
Although sleep requirements vary from individual to individual and across species, a complete lack of it is deadly. But no one knows why.
