Neurofunctional Alterations of Cognitive Down-Regulation of Craving in Quitting Motivated Smokers

Objective: Cognitive down-regulation of craving involves a neural network within the prefrontal cortex. Tobacco use disorder (TUD) and trait impulsivity have been associated with prefrontal cortex impairments and down-regulation deficits. However, general deficits in down-regulation of craving (regarding non-drug-related cues) compared to never-smokers (NS), differential alterations between drug-related and non-drug-related cues, as well as its links to subject characteristics (smoking severity, trait impulsivity) have so far sparsely been investigated in TUD. Method: In this study, 78 subjects (37 TUD & 42 NS) underwent functional magnetic resonance imaging while performing a down-regulation of craving task. Two reward cue-types were presented (drug cues and alternative rewards). Subjects applied down-regulation of craving during a LATER condition and up-regulated their craving during a NOW condition. Subjective craving ratings were assessed after each trial. To evaluate down-regulation of craving, we investigated the LATER versus NOW condition. Results: TUD subjects showed no differences in down-regulation on a behavioral level, neither compared to NS nor between the two reward cue-types. On a neurofunctional level, we found a stronger BOLD response in the middle temporal gyrus in TUD subjects compared to NS in the alternative reward condition. No differences between the two reward cue-types were found within TUD subjects. During down-regulation across both reward cue-types, we identified significant negative associations between activation of control areas and smoking severity. Conclusions: Results neither indicate evidence for the expected general alterations in down-regulation of craving in TUD, compared to NS, nor specific alterations between drug-related and alternative reward cues on a neurofunctional level. Public Health Significance Statement This study shows that quitting motivated smokers can successfully down-regulate their craving for cigarettes by applying cognitive strategies. Compared to alternative rewards (within-subject comparison) and a group of never-smokers (between-subject comparison), we did not observe the expected alterations in quitting motivated smokers during down-regulation of craving, neither on a behavioral nor on a neurofunctional level. Within the group of quitting motivated smokers, results suggest that heavy smokers may show deficits during cognitive down-regulation of craving processes.