Brain Imaging in Tobacco Smokers During a Quit Attempt

The proposed study will help fill gaps in existing research by determining if nicotine-dependent cigarette smokers show changes in I?7 nicotinic acetylcholine receptor (nAChR) availability when compared to matched historical controls using positron emission tomography (PET) imaging and the radioactive ligand [18F]-ASEM (3-(1,4-diazabicyclo[3.2.2]nonan-4-yl)-6 [18F]fluorodibenzo[b,d]thiophene 5,5-dioxide), an I?7 nAChR antagonist. The study will also explore whether I?7 nAChR availability influences clinically relevant measures of tobacco abstinence (e.g., withdrawal and craving, cognitive impairment), self-reported cigarettes per day, and time to relapse during an 8-day quit attempt during which smokers can receive escalating payments contingent upon providing objective evidence (breath CO and urinary cotinine) of smoking abstinence.