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Study says sleep ‘cleans’ the brain of toxins

Photo: RelaxingMusic via Flickr

Last week, researchers from the University of Rochester Medical Center released a new study in the journal Science that demonstrated why fostering a healthy “waste removal system” may be one of the fundamental reasons for sleep. According to the study, brain cells shrink during sleep to open gaps between neurons and allow fluid to wash the brain clean.

The scientists used magnetic resonance imaging (MRI) in the brains of mice and found that the glymphatic system became 10 times as active while the mice were asleep. Brain cells shrink during sleep which increases the size of the interstitial space (gaps between brain tissue) allowing for more fluid to be pumped in and wash toxins away.

Maiken Nedergaard, M.D., one of the study researchers said, “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.”

Although the study was performed in mice, researchers are optimistic that replicating the experiments in an MRI machine would be quite easy to do with humans. Researchers believe then they can define the study’s true significance.

Despite the study’s human limitations, University of Minnesota sleep expert, Michael Howell, M.D., believes the study is promising.

“This study helps provide some insight into how sleep works and what might happen if it is not functioning well,” said Howell. “What we know is that sleep is important for the brain in all stages of life and critical for the development of functional neurons in childhood development and also for the processing and retention of memories. What we don’t know, however, is exactly how sleep works.”

The latest study’s researchers also suggest that the buildup of proteins in the brain may contribute to brain disorders like Alzheimer’s and Parkinson’s disease, although they admit that more research is needed.

For more on the benefits of sleep from Howell make sure to see his past commentary on Health Talk.