Researchers at the University of Rochester (USA) have carried out a study that demonstrates therestorative nature of sleepand that could explain why we need to sleep, according to the magazineSciencein its latest edition.
“We sleep to clean the brain;sleep appears to be the result of the active clearance of the by-products of neural activity that accumulate during wakefulness“Explains Maiken Nedergaard, lead author of the article, in statements to the SINC agency. Specifically, her work points out that during sleep the brain is very active in eliminating waste, such as the beta-amyloid protein responsible for the disease of Alzheimer’s and other neurological disorders.
Known as‘glymphatic system’, which was discovered last year by the same researchers, replaces the role of the system responsible for eliminating cellular waste in the rest of the body – the lymphatic system – whose function does not extend to this organ.
The brain’s process to clean debris was not known until now by scientists since, when observed only in the living brain, it was not possible until the arrival of new imaging technologies such as two-photon microscopy. Thanks to this technique, the researchers were able to observe in mice – whose brains are very similar to humans –a kind of pipe system in the blood vessels of the brain that allows cerebrospinal fluid to ‘wash out’ wasteand incorporate them into the circulatory system to end up, finally, in the liver, which removes substances harmful to the body from the blood.
Rochester scientists found thatthe glymphatic system is almost ten times more active during sleep and significantly more beta-amyloid is eliminated by the brain during sleep. One of the clues to understand that this system can be more active during sleep was the fact that the amount of energy consumed by the brain does not decrease drastically will decrease while we sleep. In addition, the researchers found that while we sleep, brain cells shrink and shrink by 60%, allowing waste to be removed more effectively.
Scientists point out that thiscontractioncreatesmore space between cells and allows cerebrospinal fluid to cleanse waste more freely through brain tissue. In contrast, when you are awake, brain cells are closer together, restricting the flow of cerebrospinal fluid.
“Understanding exactly how and when the brain activates the glymphatic system and clears debris is a first step in efforts to modulate this system and make it work more efficiently,” Nedergaard stresses.
