|A woman smokes a cigarette in Toronto, September 24, 2013. Hannah Zitner/Metro|
Olfactory conditioning during sleep could lead to behavior change, according to a new study from the Weizmann Institute of Science in Israel that says exposing sleeping smokers to the stench of rotten eggs blended with that of cigarette smoke could lead them to quit.
The concept of sleep-learning has been studied before, and a recent French study saw EEG readings suggesting participants were classifying words in their sleep.
The current study is different because the sense of smell is employed. Study author Dr. Anat Arzi says the researchers chose olfactory conditioning because it’s the only sensory stimulus that doesn’t wake individuals from sleep.
Working with a group of 66 smokers looking to quit, a group was selected to spend the night in the sleep lab, where they were observed and periodically exposed to pairs of odors: either cigarette smoke and rotten eggs or cigarette smoke and fish.
In the morning, they had no recollection of the foul odors, but they reported smoking less throughout the week that followed.
Another group was exposed to the foul odors while awake but they didn’t report smoking less the following week.
A third group was exposed to the two foul odors of rotten eggs and fish separately and to cigarette smoke separately and they didn’t report smoking less either.
The group with the best results, according to the researchers, was the group exposed to the blended odors during stage 2, non-REM sleep, for they reported having cut back 30 percent.
“We have not yet invented a way to quit smoking as you sleep,” says Dr. Arzi. “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.”
The researchers remark that olfactory conditioning may be a promising direction for addiction research because the brain’s reward center, which contributes to forming addictions such as smoking, is intertwined with other regions that process smell.
The paper was published in the Journal of Neuroscience.