New research shows that a recently discovered mechanism that removes waste products from the brain is mainly active during sleep. This revelation could transform scientific understanding of what sleep is for, and how it works and offers new directions for brain disease treatments.
The team, from University of Rochester Medical Center (URMC), write about their findings in the latest online issue of Science.
Lead author Dr. Maiken Nedergaard, co-director of URMC’s Center for Translational Neuromedicine, says:
“This study shows that the brain has different functional states when asleep and when awake. In fact, the restorative nature of sleep appears to be the result of the active clearance of the by-products of neural activity that accumulate during wakefulness.”
The purpose of sleep has puzzled scientists and philosophers for millennia. While more recent research shows sleep can help with storing and consolidating memory, this alone does not balance the huge disadvantages it poses.
From a survival point of view, sleep is rife with risk – all creatures are at their most vulnerable during sleep, especially when predators are around. But if sleep has no biological function, then could it just be an evolutionary glitch?
‘Glymphatic system’
Researchers have found that while we sleep, a mechanism removes waste from the brain – a finding they say may change the scientific understanding of sleep.
In 2012, Nedergaard and colleagues reported that by using new imaging technology on mice, they had discovered a previously unrecognized system that drains waste from the brain.