NOVA: Mysteries of Sleep Like virtually every other animal, humans need sleep to survive. But why? What do we gain from spending nearly a third of our lives in such a @最近更新中文字幕2019@defenseless state? And what's at stake if we sleep poorly? The functions of sleep have long been something of a mystery. But now scientists are peering deep into the brain to see what happens while we snooze. One study reveals that well-timed bursts of pink noise can@卫国勇士@ nudge a person's brain waves, extending periods of slow-wave, or deep, sleep. And toddlers learning new words show that @av天堂吧@taking even a short nap after learning something new can help the information stick. And when it comes to sleeping poorly@逆光中告白电视剧在线观看@, it may turn out that having interrupted sleep can be just as harmful as missing sleep altogether. As scientists come to understand the powerful role that sleep -- or lack of it -- plays in everything from memory to trauma to emotion regulation, one thing is clear: This biological function is as crucial as it is complex.