Microsleep Is A Lightning-Quick Bout Of Unconsciousness
Usually, you're either awake or asleep. Usually. But the truth is that sleep isn't an all-or-nothing condition—part of your brain can stay awake while you sleep, and part of your brain can be asleep while you're awake. One way the latter occurs is in microsleep: several-second episodes of unconsciousness, which happen most often in a sleep-deprived brain during monotonous tasks like driving, listening to a lecture, or watching a movie. Sometimes when this happens, you know it: the movement of your chin falling to your chest jerks you awake. But often, you don't.
For a study published in the January 2014 issue of Human Brain Mapping, researchers had well-rested participants track a randomly moving target on a computer monitor with a joystick for just under an hour. The continuous attention this required led to a whole lot of microsleep: participants experienced 79 microsleep episodes, on average, lasting up to six seconds each. In studies like these, participants usually recall having been wide awake the entire time. That's probably because during microsleep, it's not your whole brain that loses consciousness. It's often just a single region, or even a handful of neurons. As you might expect, experiencing microsleep during any task comes with a dip in performance. That's why it's especially dangerous to drive or operate heavy machinery when you're sleep deprived. Learn more about the importance of sleep in the videos below.