Exposure to smoking cues during an emotion recognition task can modulate limbic fMRI activation in cigarette smokers

Smoking cues (SCs) refer to smoking-associated environmental stimuli that may trigger craving and withdrawal symptoms, and predispose to relapse in smokers. Although previous brain imaging studies have explored neural responses to SCs, no study has characterized the effects of SCs on cerebral activity in smokers engaged in an attention-demanding cognitive task that is unrelated to smoking. Thirteen tobacco smokers and a demographically matched group of 13 healthy non-smokers participated in a fast event-related functional magnetic resonance imaging (fMRI) study that involved a visual task integrating SCs and neutral cues (NCs) during emotion recognition trials requiring a high level of attention. No significant SC-induced alterations were detected in smokers' behavioural performance. fMRI results show that non-smokers exhibited no difference between SC and NC trials; in contrast, smokers showed SC-induced widespread deactivations in a limbic, paralimbic and striatal network classically involved in addiction, and activation in the right dorsolateral prefrontal cortex. In addition, a correlation between deactivation of the right insula and the severity of smoking dependence (Fagerström test) was detected in smokers. These results suggest that the neural reactivity of smokers to SCs can be modified in the context of a cognitive challenge. This could reflect smokers' ability to inhibit cue-induced craving and may help in smoking cessation.