Waves of Fluid Bathe the Sleeping Brain, Perhaps to Clear Waste

During deep sleep, rhythmic pulses of cerebrospinal fluid are coupled with slow waves of electrical activity and fluctuating blood levels in the human brain.

Written byAbby Olena, PhD
| 3 min read

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ABOVE: During sleep, waves of fluid surge into the brain and can be visualized with functional MRI. At an earlier timepoint (left), a wave of blood (red) is followed (right) by a pulse of cerebrospinal fluid (blue) into the fourth ventricle.
LAURA LEWIS

While humans sleep, huge waves of the cerebrospinal fluid that envelops the brain rhythmically flow in and out of the organ, according to a new study published today (October 31) in Science. The authors show that these CSF dynamics are connected to slow waves of neuronal activity, which are characteristic of deep sleep, and corresponding oscillations in the brain’s blood volume. Coupled with recent indications that CSF clears waste products from the brain, the findings shed light on the benefits of sleep for the central nervous system.

The work “is exciting because it’s linking neural activity to blood flow and cleaning the brain. Most neuroscientists would not say ...

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  • abby olena

    As a freelancer for The Scientist, Abby reports on new developments in life science for the website. She has a PhD from Vanderbilt University and got her start in science journalism as the Chicago Tribune’s AAAS Mass Media Fellow in 2013. Following a stint as an intern for The Scientist, Abby was a postdoc in science communication at Duke University, where she developed and taught courses to help scientists share their research. In addition to her work as a science journalist, she leads science writing and communication workshops and co-produces a conversational podcast. She is based in Alabama.  

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