THE length of the brief awakenings in mammals’ sleep follow a mathematical law, regardless of the size of the animals, and are not random as previously thought. This suggests there is a common underlying neural structure governing sleep in mammals.
Chung-Chuan Lo of Brandeis University in Waltham, Massachusetts, and his colleagues attached electrodes to the scalp, eyes and muscles of five mice, six rats, nine cats and 52 people to measure their electrical signatures of sleep and wakefulness. They found that the distribution of the periods of wakefulness followed an almost identical power law for all the species: the probability…
