From Harvard Gazette:
We spend about a third of our lives asleep. What really goes on during this time? The answer: more than anyone ever dreamed. This research is based on well-established findings that the brain doesn’t stop working when we sleep. During as much as 20 percent of our sleeping time, we exhibit rapid bursts of eye movements, and our brains are almost as active as when we are awake. Called REM (rapid eye movement) sleep, these are periods of vivid dreaming. During the rest of our sleep, even though consciousness is greatly diminished, our brain cells remain surprisingly active.
“Studies show that hallucinatory mental content is lowest during active waking and highest during REM sleep,” says Allan Hobson, a professor of psychiatry at Harvard Medical School. “The incidence of thinking is highest during quiet waking and lowest during REM sleep. The implication of these findings is that the sleeping brain can either generate its own perceptions or it can think about them. It cannot do both at the same time. Therefore, dreaming is as hallucinatory and thoughtless (delusional) as so-called mental illness.”
Think of that next time you try to make sense out of your dreams.
More here.