Being deprived of sleep even for one night makes the brain unstable and prone to sudden shutdowns akin to a power failure -- brief lapses that hover between sleep and wakefulness, researchers said on Tuesday.

"It's as though it is both asleep and awake and they are switching between each other very rapidly," said David Dinges of the University of Pennsylvania School of Medicine, whose study appears in the Journal of Neuroscience.

"Imagine you are sitting in a room watching a movie with the lights on. In a stable brain, the lights stay on all the time. In a sleepy brain, the lights suddenly go off," Dinges said in a telephone interview.