According to a new study, the brain uses sleep to wash away the waste toxins built up during a hard day’s thinking.
The US team conducting the new research, believe the “waste removal system” is one of the fundamental reasons for sleep.
Their study, published in the journal Science, showed brain cells shrink during sleep to open up the gaps between neurons and allow fluid to wash the brain clean.
They also suggest that failing to clear away some toxic proteins may play a role in brain disorders.
It has been shown to have a big role in the fixing of memories in the brain and learning, but a team at the University of Rochester Medical Centre believe that “housework” may be one of the primary reasons for sleep.
“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,” said researcher Dr. Maiken Nedergaard.
“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.”
Their findings build on last year’s discovery of the brain’s own network of plumbing pipes – known as the glymphatic system – which carry waste material out of the brain.
Scientists, who imaged the brains of mice, showed that the glymphatic system became 10-times more active when the mice were asleep.
Cells in the brain, probably the glial cells which keep nerve cells alive, shrink during sleep. This increases the size of the interstitial space, the gaps between brain tissue, allowing more fluid to be pumped in and wash the toxins away.
Dr. Maiken Nedergaard said this was a “vital” function for staying alive, but did not appear to be possible while the mind was awake.
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