Wake up and smell the coffee. Or stay asleep and smell it. You might learn something either way. People can make new scent associations while they slumber, which suggests that sleep has real learning potential.
鈥淲e know we can consolidate the day鈥檚 information while we sleep,鈥� says at the Weizmann Institute of Science in Rehovot, Israel. 鈥淏ut attempts to teach new facts using verbal information have failed.鈥�
Arzi and colleagues tried a different tact. They used smells instead of words. While subjects slept, the team played different sounds, each followed by the release of a specific aroma. Just as they would when awake, the sleeping subjects took deeper sniffs in response to pleasant scents and shallower sniffs in response to unpleasant scents.
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Later, the sounds alone were enough to provoke deeper or shallower breaths 鈥� even when the volunteers were awake.
鈥淲e are able to do more than we thought while we sleep,鈥� says Arzi. 鈥淚t鈥檒l be great to find the limits of what we can learn.鈥�
at New York University Langone Medical Center in Orangeburg, who was not involved in the current work, is particularly excited by this new insight into odour-processing. 鈥淲e thought the olfactory system went offline during sleep, but this study shows that some information is going in and being retained,鈥� he says.
Although it is hard to imagine translating algebra into odours, Wilson envisages practical uses for developing scent associations during sleep. They could help train people with breathing disorders like sleep apnoea to inhale deeply on cue.
Journal reference: , DOI: 10.1038/nn.3193
