Having long tossed and turned over the question of why sleep is restorative, scientists have awoken to an answer: the brain’s self-cleaning system is most effective when we slumber. Last year, researchers discovered the glymphatic system – a network of channels between brain cells through which cerebral spinal fluid flows to wash out waste products. Now, by looking at the flow of dyed fluids in the brains of mice, the same group has shown that these channels are 60 percent larger during sleep. The expansion allows for fluid to slosh more freely through the brain in sleeping mice (bottom, red) than waking mice (top, green), which ensures that waste products are flushed out more efficiently. The findings help explain why our brains work better after a good night’s sleep. They may also help scientists figure out new ways to treat brain diseases caused by a build-up of cellular waste products.
Written by Daniel Cossins
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