Scientists Kept People’s Eyes Open While They Slept, Revealing Surprising Brain Activity

Though sleep is a time to power down and replenish our energy, our brains remain surprisingly active when we’re at rest. In fact, more goes on behind our closed eyelids than we previously thought, according to a team of researchers that recently analyzed eye movements during slumber. In a study published Wednesday in the journal Nature Communications, researchers in Switzerland analyzed the pupils of sleeping participants. The study reveals that our pupils constantly change size while we’re unconscious, indicating different levels of brain activation—the brain’s response to stimuli. With further research, doctors might one day use pupil activity to diagnose conditions such as sleep disorders. Pupil dynamics “reflect the state of arousal, or the level of brain activation in regions that are responsible for sleep-wake regulation,” said Caroline Lustenberger, a neuroscientist at ETH Zürich and co-author of the study, in a university statement. “These observations contradict the previous ... Read full article.