New research described by Discover suggests that parts of the brain may enter a sleep-like state during the day.

Recordings from the electrodes were constantly acquired over a period of several days and nights, so Slater et al. were able to determine which features of the brain activity were most characteristic of sleep as opposed to wakefulness.

It turned out that across the brain, sleep was strongly associated with two things: an increase in the amplitude of delta waves, and a fall in the peak frequency of alpha waves. This isn’t a new finding, but Slater et al. went on to examine whether each electrode was showing activity more characteristic of sleep or waking at any given time.