But scientists had long been blinkered by preconceptions about the sleeping brain. It remains an astonishing anachronism in the history of science that Watson and Crick unraveled the structure of DNA before virtually anything was known about the physiological condition in which people spend one-third of their lives. As Tom Roth, the former editor of the journal Sleep, put it: “It’s analogous to going to Mars with a third of the Earth’s surface still unexplored.” The REM state is so important that some scientists have designated it a “third state of being” (after wakefulness and sleep), yet the phenomenon itself remained hidden in plain sight until September 1953, when the experiments conducted in Chicago by Aserinsky were published.
His now-classic paper, coauthored by advisor Kleitman, was less important for what it revealed than what it began. REM opened the terra incognita of the sleeping brain to scientific exploration. Before REM, it was assumed that sleep was a passive state; absent stimulation, the brain simply switched off at night like a desk lamp. After REM, scientists saw that the sleeping brain actually cycled between two distinct electrical and biochemical climates—one characterized by deep, slow-wave sleep, which is sometimes called “quiet sleep” and is now known as non-REM or NREM sleep, and the other characterized by REM sleep, also sometimes called “active” or “paradoxical” sleep. The mind in REM sleep teems with vivid dreams; some brain structures consume oxygen and glucose at rates equal to or higher than in waking. The surprising implication is that the brain, which generates and evidently benefits from sleep, seems to be too busy to get any sleep itself.
The discovery of REM launched a new branch of medicine, leading to the diagnosis and treatment of sleep disorders that afflict tens of millions of people. It also changed the way we view our dreams and ourselves. It shifted scientists’ focus from the dreaming person to the dreaming brain, and inspired new models in which the chimerical dramas of the night were said to reflect random neural fireworks rather than the hidden intentions of unconscious conflict or the escapades of disembodied souls. By showing that the brain cycles through various neurodynamic phases, the discovery of REM underscored the view that the “self” is not a fixed state but reflects fluctuating brain chemistry and electrical activity. Many researchers continue to hope that REM may yet provide a link between the physical activity of the brain during a dream and the experience of dreaming itself.
It’s hard to overestimate the importance of Aserinsky’s breakthrough, said Bert States, an emeritus professor of dramatic arts at the University of California at Santa Barbara and the author of three books on dreams and dreaming: “The discovery of REM sleep was just about as significant to the study of cognition as the invention of the telescope was to the study of the stars.”
In 1950, when Aserinsky knocked on Nathaniel Kleitman’s office door, Kleitman, then 55, was considered the “father of modern sleep research.” A Russian émigré, he had received a doctorate from the University of Chicago in 1923 and joined the faculty two years later. There he set up the world’s first sleep lab. The cot where research subjects slept was pitched under a metal hood formerly used to suck out noxious lab fumes.