How the brain cleans sleeping

How the brain cleans sleeping

Sleep is also used to perform a large biological cleansing of the brain. This discovery opens up research opportunities for Alzheimer's disease

Aquoi serves sleep? Why do we spend about a third of our lives sleeping? We knew that it was essential to some important cognitive functions such as memory consolidation. But it was not until now that he had a fundamental biological role. Maiken Nedergaard The découvertede and colleagues from the University of Rochester, in the US, for the first time shows that sleep is also used to clean our brain metabolic waste produced by the activity of neurons. In 2012, the US team had already established, in mice, the cerebrospinal fluid, clear fluid that bathes the spinal cord and brain and is levied at a lumbar puncture was used to evacuate to the venous system waste toxic by brain cells. The last work of Rochester researchers published in 2013 goes further by showing that the bulk of this cerebral cleaning takes place during sleep.

Sleep, eliminate!

To do this, they injected into the mouse spinal fluid a green fluorescent marker when they slept, and another marker, red when they wake up. They then observed in vivo, with a high-powered microscope, the interstitial space, the area between the capillaries and the cells, dilated during sleep. While it occupies only 14% of the volume of the brain in awake mice, the interstitial space passes 23% of the sleeping animal. This dilation increases accordingly cleaning efficiency: cerebrospinal fluid, which remains on the surface of the cortex during wakefulness, penetrates in depth during sleep, allowing it to evacuate much more waste to the channels Venous.

Alzheimer's disease

The Rochester team did not stop there. It also assessed the impact of this on the beta-amyloid protein. Those with the Tau protein accumulates in the brains of people with Alzheimer's disease. Of patients also are known to have significant sleep disturbances. After injecting beta-amyloid proteins in the brain asleep and awake mice, the team found that they were eliminated twice as fast during sleep than during wakefulness. If this cleaning work identically in humans, this discovery could open new avenues for prevention and treatment of Alzheimer's disease and neurodegenerative diseases every where there is a neurotoxic waste accumulation in the brain . It will explore for example if the cleaning is not associated with sleep stages that are related to memory.

Tagged : How the brain cleans sleeping, How the brain, cleans sleeping.