In fact, when the lights go out, our brains start working–but in an altogether different way than when we’re awake. At night, a legion of neurons springs into action, and like any well-trained platoon, the cells work in perfect synchrony, pulsing with electrical signals that wash over the brain with a soothing, hypnotic flow. Meanwhile, data processors sort through the reams of information that flooded the brain all day at a pace too overwhelming to handle in real time. The brain also runs checks on itself to ensure that the exquisite balance of hormones, enzymes and proteins isn’t too far off-kilter. And all the while, cleaners follow in close pursuit to sweep out the toxic detritus that the brain doesn’t need and which can cause all kinds of problems if it builds up.
Alice Park in TIME Magazine (Sep-14)