See this vision during the day, wide awake, and you may be diagnosed as mad. See the same scenes at night, sound asleep and snug in bed, and you'll be judged perfectly normal; it's all but a dream.
Scientists and artists alike have long been fascinated by dreams. Our nighttime fantasies have always been something of a mystery to our daytime minds, poets and scholars wondering what meaning might be encoded in the often bizarre visions. Now J. Allan Hobson, professor of psychiatry and director of the neurophysiology laboratory at the Massachusetts Mental Health Center, is finding reason anew for probing dreams: By exploring the brain activity associated with our nighttime worlds, he hopes to learn more about the causes of psychosis.
"Dreaming is trying to tell us what psychosis is like," he says. "If we can understand dreaming, a normal psychosis with known physiological underpinnings, then we can begin to build blueprints for how the brain goes mad."
In so doing, Hobson's approach contrasts sharply with the age-old idea that dreams should be studied for their narrative content, the tales seen as clues to hidden worlds. Sigmund Freud, of course, saw dreams as an expression of the wants and fears of the subconscious.
"Interpretive theories are not scientific and can't be proven," he says. "Dreaming has not been properly studied because the research emphasis has been on dreams as a story, not a mind-brain experience."
In his latest contribution to dream research, Hobson published a series of eight papers in the journal Consciousness and Cognition that reported studies examining the dreams of approximately 100 people, including 14 children ages 4 to 10. The studies took three years and involved analyzing more than 1,000 dreams.
In his analysis, Hobson examined a number of questions: What type of "thinking" characterizes dreaming? How self aware are we when we dream? In what ways are dreams bizarre? What are the most common emotions experienced while dreaming?
Although the articles published in Consciousness and Cognition focus specifically on those characteristics, this research has led Hobson to identify the many parallels between the dream state and psychosis. For example, the type of "thinking" during dreaming is of a "low order"-that is to say, not very complete.
"It's related to being unable to concentrate," he explains. "You can't pay attention in dreams. By the time you've noticed the picture, the scene has changed from a museum to your grandmother's house. But you don't say to yourself, 'that shouldn't be happening' or 'that's an interesting scene; I think I'll go have a closer look at it.' Insight is nonexistent-precisely like being crazy."
Hobson also looked at what made dreams bizarre. "People wake up and say they had a strange dream, but what was strange about it?" Hobson asks. "In what way is it not like the waking state?"
The bizarre nature of dreams, he continues, is caused by an absence of orientation. "Orientation is the accurate representation of time and place and person," he explains. "Who are we, whom are we talking to, what are we talking about, where is it, and what time is it? If you didn't know any one of those things, you'd be operating without a compass. In dreams, times and places and persons change without notice so the very ground of cognitive experience is being shifted."
Another characteristic of dreams: This mental state is typically a more emotional one than our waking state. And more often than not, Hobson found, the emotion is not a pleasant one. Anxiety was the most common emotion reported by the subjects during their 1,000 nights of dreaming, followed by elation, anger, sadness and guilt. In all, more than two-thirds of the emotions reported were negative ones.
As for why our dreams should be this way, Hobson looks for answers not in our hidden feelings, but in the brain chemistry associated with REM sleep. In particular, Hobson points to changes in the levels of three chemicals to explain our mental activity while asleep.
Norepinephrine and serotonin are known to be essential for various mental activities while we are awake. However, these two chemicals are in short supply during sleep. The neurons in the brain stem that produce these neurotransmitters shut down completely during REM sleep, which is the period of sleep associated with dreaming.
"We believe, as others have suggested, that memory, attention and the other features lacking in a dream state probably depend on the presence of those chemicals," Hobson says.
The third key change in brain chemistry during sleep is a dramatic increase in acetylcholine. "The brain is being squirted full of this stuff, and it drives you nuts. Your visual and emotional centers are being bombarded. You are basically having a modified seizure."
Although the reason for these changes in brain chemistry have not yet been adequately explained-what purpose might they serve?„Hobson is willing to speculate: "It could be the brain is doing a balancing act with these chemicals. If you're awake too long, the neurons become desensitized and so you turn them off for a while."
This description of the dream state-both in terms of the type of "thinking" involved and changes in brain chemistry-does suggest parallels between dreams and abnormal waking states, such as psychotic depression and schizophrenia. Many such conditions are characterized by abnormal levels of neurotransmitters, including serotonin.
One key aspect of Hobson's latest research is that the subjects recorded their dreams at home, rather than in a hospital setting. Hobson invented and refined a sleep monitoring device, called a Nightcap, that made this transition to a natural setting possible.
The device is basically a bandana, with sensors attached to the eyelid and forehead for recording eye and head movements, information that can be used to identify sleep stages. The subjects used a hand-held tape recorder to detail their dreams when they awoke.
The "Nightcap" has quickened Hobson's research and greatly reduced its cost. For example, during the three weeks between Thanksgiving and Christmas in 1992, Hobson gathered 230 dream reports from 10 subjects sleeping at home, and at one-tenth the usual cost. If done in a sleep lab, it would have taken 1.5 years to gather this data, and cost $1,000 for every time a subject spent a night in the lab.
And, says Hobson, the dreams were longer, richer, and contained more personal information than those typically reported in a sleep lab. "People who sleep in sleep labs tend to dream about the sleep lab," he says.
--Janice Perrone