Original photo by © cottonbro studio/Pexels.com
Your brain works hard all day, processing information that comes in at a staggering rate of 1 billion bits per second. It’s no wonder, then, that it needs some downtime to freshen up. Scientists have long theorized that humans and other animals need sleep because it helps maintain the brain, but they’ve also discovered that, during sleep, the brain is literally washed with fluid in a sort of rinse cycle that clears out chemical waste.
Oops, incorrect!
It's a fibYour entire brain is active all the time — when you’re doing math, when you’re watching TV, and even when you’re asleep. The myth that people use only 10% of their brains began before our modern scientific understanding of the brain.
A waste clearance network called the glymphatic system is responsible for this brain rinse, which is thought to happen largely when we’re asleep. Unlike other parts of the body, the brain doesn’t have lymphatic vessels to help it move fluids around. However, it does seem to have developed a work-around: In a study with mice, researchers found that blood volume and cerebrospinal fluid levels varied in response to pulses of norepinephrine, a neurotransmitter found in the brain that regulates alertness and affects your sleep-wake cycle, among other things.
Norepinephrine pulses cause the brain’s blood vessels to clench — and, with the hard wall of the skull creating resistance, that clenching action creates a pumping effect. Cerebrospinal fluid moves in to fill the gap made by the clenching vessels. When the blood vessels relax, the fluid is moved out again, carrying away waste.
Numbers Don't Lie
More Interesting Reads
Nearly 60% of the human brain is made up of ______.
Ready to reveal?
Confirm your email to play the next question?
Nearly 60% of the human brain is made up of fat.
Your gut contains a “second brain.”
Within your digestive system lies the enteric nervous system (ENS), often called the “second brain.” It stretches throughout the gastrointestinal tract from the esophagus all the way down to the rectum. This “little brain” controls digestion, from swallowing your food to breaking it down and absorbing its nutrients. The little brain also talks to the big brain, which may explain why you feel “butterflies” in your stomach when you’re excited or stressed.
Researchers used to think that gut conditions such as irritable bowel syndrome were caused or exacerbated by mental health complaints such as anxiety and depression, but they’ve since found evidence that irritation in the ENS may reroute those mood change signals back to the big brain instead.
Ali Eldridge is a writer and editor based in Chicago. Currently the editor of "What on Earth! Magazine," she has also contributed extensively to Encyclopaedia Britannica and published several books for children. She spends much of her free time learning new languages and trading puns with her clever kid.
top picks from the Inbox Studio network
Interesting Facts is part of Inbox Studio, an email-first media company. *Indicates a third-party property.
