Test subjects exposed to the scent of a rose during memory training recall more if exposed to the same scent as they sleep the night before testing, reports Nature-
"Jan Born of the University of Lübeck and his colleagues exposed people to the smell of roses one evening while they learned the locations of various picture cards laid in a square. Half of them were then given the same odour to smell as they slept, while the other half had an odour-free night. When they were tested the next day, those who'd had a rosy sleep remembered 97% of the locations — without the roses this figure was 86%."
This confirms earlier, anecdotal ,reports involving brimstone, madelaines , and napalm in the morning. but other researchers have discovered that rats trained to fear sounds , given a drug known to cause limited amnesia , U0126 , which is not approved for human use , were no longer afraid of the sound they had been reminded of under treatment.
Amateur plant breeders should not attempt to promote the expression of UO126 by rose DNA, as an unforgettable regulatory katzenjammer may result if Greenpeace gets wind of it.
|Published online: 8 March 2007; | doi:10.1038/news070305-10
Rose-scented sleep improves memoryBursts of scent during the night can help solidify learning.
Taking a whiff of rose scent while learning a task and then being exposed to the same smell during sleep helps memories to set, researchers have found. The discovery could see students frantically spraying themselves with perfume before exams — although the effect is tricky to replicate at home.
Jan Born of the University of Lübeck and his colleagues exposed people to the smell of roses one evening while they learned the locations of various picture cards laid in a square. Half of them were then given the same odour to smell as they slept, while the other half had an odour-free night. When they were tested the next day, those who'd had a rosy sleep remembered 97% of the locations — without the roses this figure was 86%.
The team's findings, published in Science1, supports theories about how memories are solidified in the brain during sleep.
Researchers think that a part of the brain called the hippocampus is like the scratch-pad of memory, where we put new things that have been experienced or learned until they can be filed for long-term storage. During sleep, these memories are 'reactivated' and transferred to the cortex.
Odours are known to have a potent effect on the hippocampus. Born and his team speculated that an odour could thus help to trigger the 'reactivation' process during sleep, making permanent memory storage more efficient. Their tests support this theory. "By experimentally inducing it, we can show that reactivation enhances memory," says Born.
On again, off again
But simply sleeping in a rose-scented room won't necessarily do the trick, because the timing of odour exposure is crucial.
But because people get used to odours very quickly, the odour had to be turned on and off at the right times to get the memory effect.
You might think that a whiff of roses the following day, while being tested, would help the volunteers remember the card locations. But the researchers found that this didn't improve the volunteers' scores — though Born doesn't rule it out. The same mechanisms are involved in securing memory during sleep and when awake, he says — the difference is that the hippocampus is more sensitive when its owner is sleeping.
Don't do this at home
It's hard to tell the difference between slow-wave and other types of sleep without being hooked up to a brain scanner, making it a difficult technique to perfect at home. "It's difficult to imagine that we can create a machine that can improve memory during sleep," says Philippe Peigneux, a sleep researcher at the Brussels Free University in Belgium. For students, simply revising what you have to learn and then getting a good night's shut-eye might prove infinitely more practical.
But the finding might provide a friendlier way to improve memory than other suggested techniques, says Born.
Born's group published a study in Nature last year that showed an increase in memory when people's brains were stimulated with a mild electric current2. "Everyone's afraid of shocking the brain," he says. "Odour presentation is a much 'softer' method."