Study Finds Brain May Use Sleep to Flush Out Toxins

Posted on October 17, 2013

Dye in a mouse brain in sleep study


A new study has found that sleep may help flush toxins out of the brain. Researchers observed mice brains in the study. They found that the space between brain cells in the mice brains increased by 60% when the mice were sleeping or anesthetized. The researchers say this increased spacing may allow the brain to flush out toxins that build up during waking hours. The finding could help explain why sleep is crucial for health. The scientists say we must sleep in order for our brain's "microscopic cleaning system" to function properly.

The researchers inserted a fluorescent dye into the brain of mice in the study. The above image shows the dye flowing through the brain of a sleeping mouse.

Maiken Nedergaard, M.D., D.M.Sc., co-director of the Center for Translational Neuromedicine at the University of Rochester Medical Center in New York, and a leader of the study, said in a statement, "Sleep changes the cellular structure of the brain. It appears to be a completely different state." She also says, "We were surprised by how little flow there was into the brain when the mice were awake. It suggested that the space between brain cells changed greatly between conscious and unconscious states."

The research found that a plumbing system, called the glymphatic system, may open, letting fluid flow rapidly through the brain. Dr. Nedergaard's lab recently discovered the glymphatic system helps control the flow of cerebrospinal fluid (CSF), a clear liquid surrounding the brain and spinal cord.

Roderick Corriveau, Ph.D., a program director at NINDS, says, "It's as if Dr. Nedergaard and her colleagues have uncovered a network of hidden caves and these exciting results highlight the potential importance of the network in normal brain function."

Take a look:



The study was funded by the National Institute of Neurological Disorders and Stroke (NINDS), part of the NIH. The results were published here in the journal, Science.

Photo: Courtesy of Nedergaard Lab, University of Rochester Medical Center