How Your Brain Cleans Itself—Mystery Solved?
Talk about brainwashing—a newfound plumbing system, identified in mice, likely helps the brain empty its waste, a new study says. Because mouse biology is similar to ours, the same findings should apply to people too, experts say.
Thanks to a blood-brain barrier—a natural wall that protects the brain tissue—the organ never touches blood, thus protecting it from microbes, viruses, and other pathogens.
To get nutrients to brain tissue and remove its waste, the brain makes a liquid called cerebrospinal fluid. But exactly how the fluid removes gunk generated by brain cells wasn’t certain until now.
Experiments in the 1950s and ’60s hinted that diffusion—the passive method by which, say, food coloring spreads out in a glass of water—moved cerebrospinal fluid around the brain.
Yet this process is too slow to explain the brain’s lightning-fast activity and immaculate cleanliness.
It turns out that, while studying brain tissue, the researchers in the 1950s and ’60s unwittingly turned off the plumbing that washes the tissue.
“The idea of a cleaning system based on pressure has been around for a long time, but if you open the skull anywhere, like a hydraulic pump, it stops. They thought [the cleaning system] didn’t exist,” said study leader Maiken Nedergaard, a neuroscientist at the University of Rochester Medical Center.
The pump system is “on the order of a thousand times faster than diffusion,” she said. “I’m surprised that no one had discovered this until now.”