In a study on mice, scientists showed how the brain washes itself during sleep

While you sleep, your brain does some maintenance, including getting rid of waste. Now scientists have identified how this “flushing” occurs in mouse brains, and because we have a similar flushing system, the research could have important implications for human brains, too. Their test appeared in the magazine Cell on Wednesday.

“It’s like turning on the dishwasher before going to bed and waking up with a clean brain,” senior author Majken Nedergaarda neurologist from the universities of Rochester and the University of Copenhagen, says in: statement. “We’re basically asking what drives this process and trying to define restorative sleep based on glymphatic clearance.”

Nedergaard and other colleagues discovered the glymphatic system—responsible for removing waste in the brain—in 2012. The glymphatic system moves a clear fluid called cerebrospinal fluid around the brain to flush out toxic proteins that accumulate during waking hours. AND 2013 study suggested that rinsing occurs specifically during sleep, although this has emerged more recently tests questioned this, hypothesizing that this process occurs faster during waking hours. Either way, scientists didn’t understand how the waste disposal system could work during sleep – until now.

A new study shows that during non-rapid eye movement in mice (non-REM) sleep, the brainstem releases waves of norepinephrine (a known adrenaline-like hormone) approximately every 50 seconds, which causes blood vessels to constrict. This also creates a pulsing pattern that generates an oscillating blood volume, which in turn drives the flow of cerebral fluid that washes away toxins. Simply put, noradrenaline creates a pump effect that pushes fluid around the brain to flush out accumulated waste.

“This oscillatory constriction-dilation drives glymphatic flow,” explains Nedergaard Popular scienceTom Hawking.

“We have identified perhaps the most important factor that stimulates glymphatic flow during non-REM sleep,” says Nedergaard ScienceMitch Leslie. According to the study, the correlation between noradrenaline release and changes in cerebral blood volume was stronger during restful non-REM sleep than during more active sleep. REM sleep or waking hours.

The team then tested the impact Zolpidem (a popular sleep aid, also known as Ambien or Zolpimist) on this system and found that in mice treated with zolpidem, noradrenaline waves during sleep were reduced by 50 percent and fluid transport to the brain was reduced by about 30 percent. These results suggest that sleep medications that affect norepinephrine production – which most sleep medications include – may harm the brain’s waste disposal system.

“Human sleep architecture is still very different from mouse sleep architecture, but we have the same brain circuitry that we studied here,” he added. Laura Lewis– says a neuroscientist from the Massachusetts Institute of Technology who was not involved in the study New scientistGrace Wade. “Some of these basic mechanisms will likely apply to us as well.”

“More and more people are taking sleep medications, and it’s really important to know if it’s healthy sleep,” lead author Natalie Hauglund– says a neuroscientist from the universities of Copenhagen and Oxford in a statement. “If people aren’t getting the full benefits of sleep, they need to be aware of it so they can make informed decisions.”

Further research on this topic could shed light on how to help people achieve healthy sleep, as well as provide insight into neurological disorders related to toxic proteins normally flushed from the brain.