In a study recently published in the journal Neuropsychopharmacology, researchers at the Montreal Neurological Institute (MNI) and the Department of Psychology at McGill University found that when people expect to smoke in the near future, external cues such as watching someone smoke affects their brain more than their level of craving or how long they have gone without a cigarette.
The research was conducted at the MNI's McConnell Brain Imaging Centre, where subjects were scanned using fMRI (functional Magnetic Resonance Imaging). Twenty healthy smokers were recruited for the study and were randomly divided into one of two groups: "expectant" (they could smoke right after the test) or "non-expectant" (they could only smoke four hours after the test). The researchers scanned the brains of each subject to pinpoint the areas that were active while the subjects were exposed to visual smoking cues through videotaped footage of people lighting cigarettes, smoking while socializing or blowing smoke rings. In the group who expected to smoke immediately after the test, areas of the brain implicated in arousal, attention, and cognitive control were activated. In the subjects who could only smoke four hours after the test, there was almost no neural response to smoking cues, even if the subject reported an equivalent craving level.
"Although the effect of exposure to drug-associated cues has been studied with various drugs of abuse, this is the first study to show the link between expectancy levels and smoking cues," explained Dr. Alain Dagher, a neurologist who specializes in functional brain imaging. "Our findings confirm the importance of expectancy in the neural response to these cues, and lend support to the theory that these cues act on brain areas involved in arousal and attention, particularly the dorsolateral prefrontal cortex, which is involved in the regulation and planning of drug-seeking or drug-avoiding behaviour."