Study involving scents, sleep and learning:

http://news.yahoo.com/s/nm/20070309/od_uk_...k_memory_smells

Excerpts:

Jan Born of the University of Lubeck in Germany and colleagues had 74 volunteers learn to play games similar to the game of "Concentration" in which they must find matched pairs of objects or cards by turning only one over at a time.

While doing this task, some of the volunteers inhaled the scent of roses. The volunteers then agreed to sleep inside an MRI tube. Functional magnetic resonance imaging was used to "watch" their brains while they slept.

At various stages during sleep, Born's team wafted in the same scent of roses.

The volunteers were tested again the next day on what they had learnt. "After the odour night, participants remembered 97.2 percent of the card pairs they had learnt before sleep," the researchers wrote.

But they only remembered 86 percent of the pairs if they did not get the rose smell while sleeping.

And the stage of sleep was important too, the researchers said in a finding that will add to the debate over whether people "learn" in their sleep the way some animals have been shown to.

Research has shown, for example, that rats learning a new maze will rehearse their movements during sleep, and that songbirds rehearse their songs.

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