graduate student in physiology, and Nathaniel Kleitman, PhD, chair of physiology at the University of Chicago, discovered the phenomenon of rapid eye movement (REM) during a series of sleep studies. Study participants who were awakened during REM sleep invariably recalled bizarre and vivid dreams. If awakened while eyes were motionless (non-REM sleep), participants rarely recalled dreaming. Before the REM discovery, most scientists believed that the brain was essentially inactive during sleep. The Chicago researchers proved that the brain is indeed active during sleep, a finding that helped establish the sleep science discipline, which has led to the diagnosis and treatment of 84 known or suspected sleep disorders.
A few years after the REM discovery, Michel Jouvet, MD, of Claude Bernard University in Lyon, France, recognized that brain activity during REM sleep resembles that of wakefulness. He called REM "paradoxical sleep" because of the fact that such cognitive activity is accompanied by muscular paralysis. He referred to non-REM sleep, a time of reduced brain activation, as "quiet sleep," in which there is no muscular inhibition.
In a pioneering study conducted by William C. Dement, MD, PhD, in 1960, the psychological effects of REM deprivation were discovered by waking subjects just as they began dreaming. Dr. Dement observed increased tension, anxiety and irritability among his subjects along with difficulty concentrating, an increase in appetite with consequent weight gain, lack of motor coordination, feelings of emptiness and depersonalization and hallucinatory tendencies. The results of this study clearly indicate that dreaming has profound importance and that dream deprivation can have very serious consequences.
Why Do We Dream?
But even with these discoveries, the question of why we dream remains unanswered. Some researchers think dreaming might have evolved for physiological reasons. There is a great deal of neuronal activity occurring while we sleep, especially in REM, and it has been suggested that dreams may just be a meaningless by-product of this biological function. Another theory of dreaming is put forth by Rosalind Cartwright, PhD, Professor and Chairman, Department of Psychology at Rush University Medical Center in Chicago. Dr. Cartwright believes that dreams are the mechanism