Depth 1
How muscles make that magic frequency
Cats do not need to think about purring; it runs on an internal biological motor powered by a neural oscillator in their brains. This circuit tells the laryngeal muscles to twitch back and forth twenty-five times every second. That specific number is magical because twenty-five hertz is a frequency scientists use in labs to help heal broken bones and grow muscles back faster. So when a kitty curls up on your lap and vibrates away, they might actually be running a built-in physical therapy session for themselves, while also melting away your stress.