Sleep Isn’t Passive: The Brain at Night

For almost two thousand years, humans believed that sleep was just the intermediate

state between wakefulness and death. Until recently, the world’s top thinkers assumed

sleep was purely passive—like a light switch being turned off because the brain stopped receiving

sensory input. They saw no real difference between sleep and a coma or even anesthesia.

It wasn't until we discovered brain waves and Rapid Eye Movements in the 1950s that we

realized the truth. Your brain isn’t "idling" or "shutting down" at night; it’s actually engaged

in a special, dynamic activity controlled by precise biological mechanisms. In some stages,

your brain is even more active than when you’re wide awake. We’re exploring