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We sleep to clear our brains of thinking, study proves

By Catholic Online (NEWS CONSORTIUM)
October 17th, 2013
Catholic Online (www.catholic.org)

A team at the University of Rochester Medical Center believe that human beings sleep in order to clear their brains of toxins while awake. This research groups says that such "housework" may be one of the primary reasons for sleep.

LOS ANGELES, CA (Catholic Online) As published in the journal Science, the study found that brain cells shrink during sleep to open up the gaps between neurons and allow fluid to wash the brain clean. This suggests that failing to clear away some toxic proteins may play a role in brain disorders, the researchers say.

One big question for sleep researchers is why do animals sleep at all when it leaves them vulnerable to predators?

"The brain only has limited energy at its disposal and it appears that it must choose between two different functional states - awake and aware or asleep and cleaning up," researcher Dr Maiken Nedergaard says.

"You can think of it like having a house party. You can either entertain the guests or clean up the house, but you can't really do both at the same time."

This coincides with a similar medical discovery made last year about The brain's own network of plumbing pipes, known as the glymphatic system - which carry waste material out of the brain. Imaging the brains of mice, research proved that the glymphatic system became 10-times more active when the mice were asleep.

The glial cells, researchers theorize, which keep nerve cells alive, shrink during sleep, increasing the size of the interstitial space, the gaps between brain tissue, allowing more fluid to be pumped in and wash the toxins away.

This is a "vital" function for life, which doesn't appear to be possible while the mind was awake.

"This is purely speculation, but it looks like the brain is losing a lot of energy when pumping water across the brain and that is probably incompatible with processing information," Nedergaard says.

The true significance of the findings would be known only after human studies, but doing similar experiments in an MRI machine would be relatively easy.

"This is a very interesting study that shows sleep is essential downtime to do some housekeeping to flush out neurotoxins," fellow sleep researcher Dr Neil Stanley says.

"There is good data on memory and learning, the psychological reason for sleep. But this is the actual physical and chemical reason for sleep, something is happening which is important."

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