Eyes dart about a dream scene in REM sleep

Abstract

One's body may be still, but as he dreams, his eyes can flicker manically. The rapid eye movement (REM) stage of sleep is when one has the most vivid dreams. Some evidence comes from a previous study that monitored the sleep of people who have a disorder that means they often physically act out their dreams. Their eye movements matched their actions around 80 percent of the time--a man dreaming about smoking, for example, appeared to look at a dream ashtray as he put out a cigarette. But most of the REM sleep these people had was not accompanied by body movements, making it hard to know for sure. To investigate further, Yuval Nir at Tel Aviv University and his colleagues monitored people who have epilepsy and have electrodes implanted deep into their brains to help with treatment. These electrodes were mostly in a region that responds strongly to pictures, and allowed the team to record the activity from around 40 neurons in each volunteer's brain as they slept. They found that activity seemed to spike around a quarter of a second after an eye flicker, just as it does after seeing an image when awake.