How often have you “slept on” a problem and found that the right answer was easily reached afterwards?
More and more research is suggesting that sleep is essential not just to recharge our energy, but to help process the day’s events and plan for the future. While scientists often use human subjects in sleep studies, the work that taps directly into brain activity is more often done with rats. But how do you listen in on brain activity in the first place? In this clip from the 2015 World Science Festival program “What is Sleep?” neuroscientist Matthew Wilson explains how it works:
Recently, a group of scientists from University College London put out a study examining the brain activity of sleeping rats after they had explored a T-shaped track. During their waking explorations, rats could see food placed in the arms of the T, but were unable to get to the treats because of a clear barrier. While the rats slept, the pattern of brain activity the scientists saw in the place cells of the hippocampus—the neurons that help us create mental maps of our surroundings—seemed to indicate that the rats were “exploring” the arms of the track to get at the food. Afterwards, when the then fully awake rats were allowed to explore the part of the track that had been previously closed off, that same brain pattern that had been seen during sleep popped up.
While it’s well known that rats will “revisit” locations in their brain during sleep, with the same place cell patterns lighting up as they did during waking exploration, seeing the pattern in sleep first is a new find. It seems as though in their dreams, the rats were imagining how they’d explore the track.
“People have talked in the past about these kind of replay and pre-play events as possibly being the substrates of dreams, but you can’t ask rats what they’re thinking or dreaming,” study author Hugo Spiers told Discover. However, “there is that really interesting sense that we’re getting at the stuff of dreams, the stuff that goes on when you’re sleeping.”
While there’s still a lot to learn about how the sleeping (human or rat) brain combs through the events of the day, in experiments the benefits of sleep on cognition are often self-evident. In another selection from “What is Sleep?” researcher Robert Stickgold (with the help of his son) illustrates the performance-enhancing powers of even just a short nap:
Whether you’re a rat or a boy, when exploring your surroundings, it appears that being well-rested is essential to success.