When inventor Thomas Edison needed inspiration, he would often nap in his chair, holding a metal ball in each hand. The moment he falls, the ball falls as well, hitting the floor and waking him up. Edison claimed that this allowed him to capture ideas that briefly emerged in his semi-consciousness while he was asleep.
The state Edison was after is called the sleep onset period (SOP), a little-studied phase of the sleep-wake cycle. Once viewed as a brief interlude between wakefulness and sleep, it is now considered a distinct and important stage in its own right. Not only is it involved in coordinating the shutdown of consciousness, but it may also play a crucial role in many functions of sleep, including memory processing and, of course, creativity.
However, for some people it can be disruptive. Insomnia and narcolepsy can be the result of it going wrong. A better understanding of SOP could lead to new treatments for these sleep conditions, while also helping anyone who wants to become more alert or creative — so “almost everyone,” says Delphine Odita cognitive neuroscientist at Sorbonne University in Paris, France.
We all experience the transition from wakefulness to sleep, sometimes several times every 24 hours, and many of us know it can be…
