What Dreams Are Made Of: Born to be Dreamers

Doctors are on the roof talking to people, saying they shouldn't be up there because it's dangerous. One doctor gives shots to immobilize the brain, rather than fixing ailments. I say if I fall to fix me up but leave my brain so I can dream.

Adult humans spend about a quarter of their sleep time in REM, much of it dreaming. During that time, the body is essentially paralyzed but the brain is buzzing. Scientists using PET and fMRI technology to watch the dreaming brain have found that one of the most active areas during REM is the limbic system, which controls our emotions. Much less active is the prefrontal cortex, which is associated with logical thinking. That could explain why dreams in REM sleep often lack a coherent story line. (Some researchers have also found that people dream in non-REM sleep as well, although those dreams generally are less vivid.)

Another active part of the brain in REM sleep is the anterior cingulate cortex, which detects discrepancies. Eric Nofzinger, director of the Sleep Neuroimaging Program at the University of Pittsburgh Medical Center, thinks that could be why people often figure out thorny problems in their dreams. "It's as if the brain surveys the internal milieu and tries to figure out what it should be doing, and whether our actions conflict with who we are," he says.

These may seem like vital mental functions, but no one has yet been able to say that REM sleep or dreaming is essential to life or even sanity. MAO inhibitors, an older class of antidepressants, essentially block REM sleep without any detectable effects, although people do get a "REM rebound"—extra REM—if they stop the medication. That's also true of selective serotonin reuptake inhibitors (SSRIs) like Prozac, which reduce dreaming by a third to a half. Even permanently losing the ability to dream doesn't have to be disabling. Israeli researcher Peretz Lavie has been observing a patient named Yuval Chamtzani, who was injured by a fragment of shrapnel that penetrated his brain when he was 19. As a result, he gets no REM sleep and doesn't remember any dreams. But Lavie says that Chamtzani, now 55, "is probably the most normal person I know and one of the most successful ones." (He's a lawyer, a painter and the editor of a puzzle column in a popular Israeli newspaper.)

The mystery of REM sleep is that even though it may not be essential, it is ubiquitous—at least in mammals and birds. But that doesn't mean all mammals and birds dream (or if they do, they're certainly not talking about it). Some researchers think REM may have evolved for physiological reasons. "One thing that's unique about mammals and birds is that they regulate body temperature," says neuroscientist Jerry Siegel, director of UCLA's Center for Sleep Research. "There's no good evidence that any coldblooded animal has REM sleep." REM sleep heats up the brain and non-REM cools it off, Siegel says, and that could mean that the changing sleep cycles allow the brain to repair itself. "It seems likely that REM sleep is filling a basic physiological function and that dreams are a kind of epiphenomenon," Siegel says—an extraneous byproduct, like foam on beer.

But dreaming may also fulfill many functions that we don't yet understand. Allan Rechtschaffen, a longtime sleep researcher and professor emeritus at the University of Chicago, compares dreaming to breathing. "We need to breathe to get oxygen," he says. "That's a physiological must. That's why the breathing apparatus evolved. But once it evolved, you can put it to other uses, like for speech or laughing or playing the saxophone." Perhaps dreaming, too, adapted to other uses. "There's no reason dreams have to be any one thing," he says. "Is our waking consciousness any one thing?"

3 Intro: We are all Fellini in the Middle of the Night

3 Page 1: History Of Dream Research

Continued

4 Page 3: Different Dreamers: Age And Gender

4 Page 4: How We Use Dreams