Dreaming Linked to Brain Development

By William J. Cromie

Gazette Staff

Hidden patterns of dreamlike activity in the brains of fetal sheep and newborn rats may aid in the understanding of brain development in humans, according to a Harvard scientist.

"Eye movements and a loss of muscle tone that characterize dreaming are thought of as random activity, but careful analysis shows they contain definite structure," says Carl Anderson, a research fellow at Harvard-affiliated McLean Hospital in Belmont, Mass. "What we are seeing, I believe, is the integration of various levels of the brain as it organizes into a feeling, learning, thinking organ."

In adult animals, including humans, similar dreamlike activity may be necessary to maintain the brain's flexibility by incorporating information from awake experiences into memory.

Organizing the Brain

From the womb to old age, humans and other animals go through periods of sleep in which their eyes continuously dart back and forth under their lids, and their brains are as active as when awake. Such rapid eye movements (REM) are frequently associated with dreaming, although dreams can occur at other times during sleep. It is generally believed that these patterns of eye movements are the result of random brain-cell activity. Anderson challenges the notion that it is random.

He obtained records of REM sleep from sheep still in the womb and from newborn rats, then analyzed them for so-called fractal patterns. Such patterns repeat themselves in a statistically similar way in different time intervals. Patterns that take place in hundredths of a second appear similar to those on scales of seconds and minutes.

Fractals are sometimes compared with a stalk of broccoli. If you break off a small piece of broccoli and look at it closely, it appears like a miniature of the stalk from which it came. If you break off an even smaller piece, the resemblance to the whole stalk still remains.

"In the same way, a pattern emerges if you look at long, continuous recordings of brain activity," Anderson declares. "Otherwise, they remain hidden."

He examined REM sleep in fetal sheep, recorded 24 hours per day for 13 days. In the womb, humans and other mammals spend 50 to 70 percent of their days in this state, and experimenters wanted to compare this REM activity with that of adults. To do that, the head of the fetus is "exteriorized" from the womb and recordings are made of its brain waves and muscle tone in the neck area.

Anderson did not do these experiments, he quickly explains. He merely analyzed the records that resulted from them. The best records came from loss of muscle tone in the neck, something that happens to humans when they nod off in an airplane or commuter train.

Nuchal atonia, as it's called, "is directly related to REM activity; both originate in the brain stem," Anderson recently reported in the scientific journal Brain Research.

"Recurrent fractal bursts associated with REM and atonia may indicate patterns of activity that integrate various regions of the brain during its development," Anderson says.

Adults don't spend half their days in REM sleep, but the process continues in order to maintain the brain's plasticity or flexibility, Anderson speculates. If this is true, dreams that occur during REM sleep may not simply be the by-product of random chemical and electric activity, but part of an ongoing process that consolidates new experiences during wakefulness into memory.

No one knows if a human fetus has dreams, but in any case, dreams may be void of direct psychological meaning.

"Dreams do not contain messages from the unconscious mind, or provide an outlet for repressed feelings," insists J. Allan Hobson, professor of psychiatry at Harvard Medical School. Psychology comes into the picture when people feel compelled to put their own interpretations on what they see and feel in dreams. It is those interpretations that tell us something about ourselves, not the actual biological changes in the brain.

The Need to Dream

Recordings of brain waves in sleeping rats provide evidence that rats incorporate some of what they learned about running mazes during the day. Tests given to humans show some improvement in scores following a good night of REM and non-REM sleep.

Whether consolidation of memories, and possibly learning, make up the sole purpose of dreams is unknown, but it is known that REM sleep is necessary for survival. When deprived of it, rats die in about 20 days.

Cats, dogs, and humans deprived of REM sleep exhibit memory and learning problems. A well-known method of torturing prisoners, REM deprivation can make a person more susceptible to suggestion and thus more likely to confess to something he or she may not have done.

Autistic children show disturbed eye movements during their REM sleep. Eye movement patterns of two- to five-year-old autistics resemble those of normal kids less than 18 months old.

Anderson interprets this finding as an indication of abnormal brain development. It may be possible, he says, to use fractal analysis of REM patterns as a way to detect autism. Another question to be answered is whether abnormal eye movements change when the children become more responsive to treatments for autism.

A number of researchers have begun to look at fractal patterns in the behavior of individuals who have other psychiatric problems in hope of finding new ways to diagnose and treat those disorders.

Anderson works with Martin Teicher, associate professor of psychiatry at McLean Hospital, who has developed fractal methods to analyze arm, leg, and head movements of kids with attention-hyperactivity disorder while they play computer games. The goal is to detect patterns of movement and correlate them with measures of brain activity, which together can be used to diagnose the condition sooner and more accurately.

Anderson himself is seeking funding to study fractal behavior in the womb to help understand how these patterns emerge and what role they may have in adult sleep patterns. He would use records collected from fetal sheep, not humans.

Anderson also wants to investigate brain activity during meditation in order to answer the question, What does meditation do? "One idea is that meditation focuses attention by bringing the two hemispheres of the brain together," he says. One side of the brain - the left in right-handed people - is dedicated to language and logic; the other is more attuned to enjoying art and music, and to spatial tasks like map reading.

"When the two are out of balance," he continues, "we may feel stressed or anxious. When in harmony, they may foster a sense of well-being. To test such ideas, we want to record and analyze brain activity during meditation and when the mind wanders."

Evidence of abnormal development shows up in REM activity of young rats deprived of contact with their mothers. Anderson would like to use these same methods to analyze the brain activity and behavioral patterns of children who have suffered sexual or verbal abuse.

Over and above such practical uses, Anderson sees fractal analysis as "providing a new way to study how biological systems organize themselves. Activity at the cellular level somehow organizes activity at higher levels, right up to the brain's cortex, which organizes behavior. Understanding how patterns integrate across levels could lead us to general principles for how all biological systems develop their complex structure. That in turn could help us understand the origin of minds and dreams."