Excerpt from The Mind at Night by Andrea Rock, plus links to reviews, author biography & more

It wasn’t long until Dement was on his own, however, because Aserinsky wasted no time clearing out of Chicago when he finished the REM experiments. Though his discovery had caused an initial flurry of public excitement, it certainly didn’t bring him fame and fortune. Feeling increasing pressure to bring home a paycheck that would support his family, he took the first job he was offered in the summer of 1953--at the Bureau of Fisheries in Seattle. There, he conducted experiments to see whether the movements of salmon could be controlled by running electric currents through water. Though it was a far cry from sleep research, a job was a job, after all, and Aserinsky was happy for the moment to put the arduous demands of all-night sleep recording sessions behind him.

Dement was thrilled to be taking the lead in dream research at the Chicago lab. Unlike Kleitman and Aserinsky, he was a great believer in Sigmund Freud’s theory that dream interpretation was the "royal road" to understanding the unconscious activities of the mind. "Freudian psychoanalysis seemed to permeate every nook and cranny of society in the 1950s and I was an ardent disciple," Dement wrote in The Sleepwatchers, an account of his early days in dream research. Since Freud had theorized that psychosis could erupt in the waking state if we didn’t have dreams as an outlet to discharge the energy of the libido, Dement eagerly set about doing REM studies on schizophrenics in a state hospital, to see whether their mental illness might spring from an inability to dream. The theory didn’t pan out--the EEG results showed they experienced normal REM cycles, and they reported having dreams.

But Dement was undaunted--he had so many other theories and unanswered questions to explore. During his final years of medical school, he spent two nights a week running sleep studies in Kleitman’s lab to more precisely define the characteristics of REM and other sleep stages. Combining those sleepless nights with the other demands of life as a medical student meant that he frequently fell asleep in the back of the classroom the following day--a problem that landed him in the dean’s office at one point--but the end result was well worth his troubles.

The paper that he and Kleitman published in 1957, describing the characteristics of REM and other sleep stages, laid the foundation for information about sleep and dreaming in most medical textbooks for decades to come, and Dement’s infectious enthusiasm for dream research helped launch similar investigations in other labs around the United States and in Europe.

By meticulously charting nightlong EEG recordings, Dement found that healthy adults pass through predictable sleep phases, which have since been divided into five standard stages of sleep. In the relaxed pre-sleep period, we begin to tune out noise and other external influences, and our brain generates the regular rhythm of alpha waves--the same kind of pattern displayed by the mind in meditation, a serene state devoid of purposeful thought. We then enter stage I sleep, also known as sleep onset, when we may experience what’s known as hypnagogic imagery--brief, dreamlike visual imagery that often is drawn from that day’s experience. Next comes stage II, a period of light sleep lasting from ten to thirty minutes, as the brain downshifts into the large, slow delta waves that characterize the deep sleep of the third and fourth stages, known as slow-wave sleep. While we may talk in our sleep at any point during the night, it is in these deepest sleep stages that sleepwalking typically occurs.

After fifteen to thirty minutes in this deep sleep, we move back up through the first two stages and enter the first of our REM periods, when our brain waves shift to the short, rapid patterns that resemble waking brain activity. When we’re in REM, our muscles completely relax, and though our eyes move and hands or feet may occasionally twitch, we are essentially paralyzed so that we can’t physically act out our dreams. Nevertheless we’re highly aroused physiologically: our breathing becomes irregular, our heart rate increases, and genitals become engorged in both males and females. The initial cycle from waking to REM normally takes between fifty and seventy minutes, and thereafter REM returns about every ninety minutes. During the first half of the night, slow-wave sleep predominates and REM periods may be as brief as ten minutes, but as the night progresses, non-REM sleep grows lighter and REM periods last longer, stretching from twenty minutes to as much as an hour as morning approaches. All told, adults spend about a quarter of the night’s sleep in REM, another quarter in deep sleep, and the remainder in stage II light sleep.

From The Mind at Night, chapter 1, pages 1-16. Copyright 2004 by Andrea Rock. All rights reserved. No part of this book may be reproduced in any manner whatsoever, except for brief quotations embodied in critical articles with reviews, without written permission from the publisher, Basic Books.