While we sleep, our brain makes cleaning the house - Público.pt

While we sleep, our brain does house cleaning

18/10/2013 – 19h16 Ana Gerschenfeld

Scientists could see flowing a liquid pigment in the brain of mice

A study published Friday in the journal Science shows a brain system responsible for blood to evacuate the “debris” produced by the brain are particularly active while we sleep.

What is sleep? The question has fascinated philosophers and scientists for centuries. Almost all animals sleep – and this in spite of so put themselves in a situation of increased vulnerability in relation to its predators.

Recent studies show that sleep serves to consolidate memories, but experts are still looking for even more vital functions of the sleep-wake cycle. Something that now Maiken Nedergaard of the University of Rochester (USA), and colleagues, may have discovered.

The new study reveals that the system called “glinfático”, identified by the same team last year in mice – and that the brain uses to remove toxins and other byproducts of neuronal activity – shows your highest level of activation during sleep.

“Our study shows that the brain is in different functional states when sleeping and when he is awake, “said Nedergaard, quoted a statement from your university. “In fact, the nature restorative sleep appears to be the result of cleaning by-products of the active neuronal activity accumulate during the waking state.”

Another surprising result obtained by the team (always in the mouse ) was brain cells “shrink” 60% during sleep. This contraction increases the space between them and allows the cerebrospinal fluid flow better, more effective debris evacuating the system glinfático – an authentic system “drains” of the brain. Scientists speculate that the hormone norepinephrine (less active during sleep) may be the “switch” that controls the contraction and expansion of the cells.

The timely removal of the “garbage” of the brain is essential: for example , undue accumulation in the brain of a person in a toxic protein called amyloid-beta may lead to Alzheimer’s disease. More, almost all neurodegenerative diseases are associated with accumulation of waste in the brain tissue cell, explains the same press.

“These results have important implications for the treatment of diseases such as Alzheimer’s disease, caused by ‘dirty’ brain, “says Nedergaard. “Understanding exactly how and when the brain activates the system glinfático and evacuates waste is a potentially crucial step to achieve this modular system and make it work more effectively.”