To Sleep, Perchance to Learn
What if, in your quest to keep your brain fit and healthy as you age, you could actually learn while you sleep? That seemingly implausible scenario turns out to be more fact than science fiction. A new study from the Weizmann Institute of Science in Israel has found that if certain odors are presented after tones during sleep, people will begin sniffing when they hear the tones alone, both when they're sleeping and when they are awake. As a press release from the journal put it: "In other words, people can learn new information while they sleep, and this can unconsciously modify their waking behavior." The research, led by Noam Sobel, was published in Nature Neuroscience.
According to the press release, sleep-learning experiments are notoriously difficult to conduct. "For one thing, one must be sure that the subjects are actually asleep and stay that way during the lessons," the release states. "The most rigorous trials of verbal sleep learning have failed to show any new knowledge taking root. While more and more research has demonstrated the importance of sleep for learning and memory consolidation, none had managed to show actual learning of new information taking place in an adult brain during sleep."
However, Professor Sobel and colleagues reasoned that the pairing of tones and odors presented several advantages: Neither one will wake up the sleeper, yet the brain processes them and even reacts during slumber. They reported that although this type of conditioning may appear simple, it is "associated with some higher brain areas – including the hippocampus, which is involved in memory formation."
Future plans will involve investigating brain processing in both sleep and coma. The release quotes Anat Arzi, a research associate who worked with Professor Sobel, as saying: “Now that we know that some kind of sleep learning is possible, we want to find where the limits lie – what information can be learned during sleep and what information cannot.”