Before the 1950’s, scientists used to believe that as people drifted off to sleep, their brains and bodies would go into "shutdown” mode, entering a passive state that allowed them to recover from the previous day. What researchers have since learned: Sleep is a whole lot more complicated, and it’s a much more active state than you might think. In fact, while you are getting your soothing sleep, your brain goes through various patterns of activity. It is a predictable cycle t