In 1975, Harvard’s Allan Hobson and Robert McCarley proposed that many properties of dreams—the vivid imagery, the bizarre events, the difficulty remembering them—could be explained by neurochemical conditions of the brain in REM sleep, including the ebb and flow of the neurotransmitters norepinephrine, serotonin and acetylcholine. Their theory stunned proponents of the idea that dreams were rooted not in neurochemistry but psychology, and it has been a starting point of dream theorizing for the past 25 years.
The once-popular description of REM as “dream sleep” is now considered an oversimplification, and debate rages over questions of what can be properly claimed about the relation of dreaming to the physiology of REM sleep. (In 2000, an entire volume of the journal Behavioral and Brain Sciences was devoted to the debate.) To be sure, you can have REM without dreaming, and you can dream without experiencing REM. But most researchers say that dreaming is probably influenced and may be facilitated by REM. Still, dissenters, some of whom adhere to psychoanalytic theory, say that REM and dreaming have little connection with each other, as suggested by clinical evidence that different brain structures control the two phenomena. In the years to come, new approaches may help clarify these disagreements. In a sort of echo of Aserinsky’s first efforts to probe the sleeping brain with EEG, some researchers have used powerful positron brain-scanning technology to focus on parts of the brain activated during REM.
This past June, more than 4,800 people attended the Associated Professional Sleep Societies’ annual meeting in Chicago. The scientists took time out to mark REM’s golden anniversary. With mock solemnity, Dement echoed the Gettysburg Address in his lecture: “Two score and ten years ago Aserinsky and Kleitman brought forth on this continent a new discipline conceived at night and dedicated to the proposition that sleep is equal to waking.”
But to paraphrase the physicist Max Planck, science advances funeral by funeral. Kleitman died in 1999 at the age of 104, and though he was a coauthor of the milestone REM study, he never really accepted that REM was anything other than a phase of especially shallow sleep. “Kleitman died still believing there was only one state of sleep,” Dement told me. Aserinsky had his own blind spots; he never relinquished his doubts that sleeping infants exhibit REM.
To honor the research done in Kleitman’s lab five decades ago, the Sleep Research Society commissioned a 65-pound zinc plaque. It now hangs in the psychiatry department at the University of Chicago Medical Center, adjacent to Abbott Hall. To be sure, the inscription—“Commemorating the 50th Anniversary of the Discovery of REMSleep by Eugene Aserinsky, Ph.D., and Nathaniel Kleitman, Ph.D., at the University of Chicago”—doesn’t speak to the poetry of a lyric moment in the history of science, a moment when, as Michel Jouvet once said, humanity came upon “a new continent in the brain.” But then, what do you expect from a plaque? If it’s the poetry of REM you want, you need wait only until tonight.