Under the Hood

Can Sleep Trigger Rhythmic Power Washing In The Brain?

Recently, a new study published Friday in the online journal Science found that a wave of fresh cerebrospinal fluid rolls into the brain for every 20 seconds whenever we sleep. Slow, consistent and rhythmic, the study hints at how this fluid reveals why sleep is very important to make sure our brains are healthy and fully functioning.

Previously, past studies have revealed that the same type of fluid, called CSF, washes over the brains of animals, driving away harmful proteins, including ones that can cause Alzheimer’s disease, guaranteeing that their brains are at its peak. Now, the new study reveals how the same type of washing happens to people that are asleep.

Brain Washing

The study was reportedly done on 13 healthy, young people in an MRI scanner, who were then observed as they fell into non-REM sleep. Once all of them were fast asleep, the scientists in charge then monitored their brain activities, using electrodes to measure their nerve cell activity, while functional MRI measured how much oxygenated blood is present to make sure the energy cells have energy to use. The movements of CSF were then tracked via the use of a form of rapid fMRI.

By using the fMRI, the scientists were able to observe how CSF rhythmically flowed into the brains and “cleansed it.” Usually, people who are awake have small “waves” of CSF flow into their brain, which then turn into “tsunami waves” once they fall asleep.

“I’ve never had something jump out at me to this degree,” Laura Lewis, study co-author, a neuroscientist and engineer at Boston University, said. “It was very striking. The waves we saw during sleep were much, much larger, and higher velocity.”

“The study elegantly links a number of seemingly unrelated topics in neuroscience, including sleep, brain waves, cerebrospinal fluid flow and blood flow, together,” Maiken Nedergaard, a neuroscientist at the University of Rochester Medical Center in New York, said.

With that in mind, Lewis and her colleagues also hypothesized that CSF waves are diminished in elderly people, especially those with neurodegenerative conditions. Per Lewis, this absence could potentially leave more toxic proteins sticking around.

Man sleeping Man sleeping. Pixabay