A new study at Weizmann Institute of Science in Rehovot shows that olfactory conditioning during sleep can affect changes in behavior. Published today in The Journal of Neuroscience, Dr. Anat Arzi of Prof. Noam Sobel‘s Olfaction Research group presented cigarette smokers who wished to quit smoking with aversive odors paired with cigarette smoke at different sleep and wake stages. When the offensive smells were introduced during sleep, members of the study smoked fewer cigarettes in the following week than they had in the previous week, even though they reported not remembering the smell after waking. The greatest reduction was when the odor was introduced immediately after cigarette smoke during stage 2 non-REM sleep, while there was no effect if subjects were awake.
We have not yet invented a way to quit smoking as you sleep. That will require a different kind of study, altogether. What we have shown is that conditioning can take place during sleep, and this conditioning can lead to real behavioral changes. Our sense of smell may be an entryway to our sleeping brain that may, in the future, help us to change addictive or harmful behavior.
Sobel and Arzi suggest that this type of conditioning could be a promising direction for addiction research because the brain’s reward center – associated with addictive behavior – is closely connected with the regions that process smell. In fact, the information that these regions absorb may even be enhanced while sleeping, making it an even more efficient target for behavioral conditioning.