 We will determine the acute effects of nicotine on attentional and other cognitive mechanisms and how emotional processes such as the anticipation and receipt of reward affects the neuronal activation properties of acute nicotine administration in experienced smokers. In addition, we will determine whether genetic polymorphisms predict BOLD response during cognitive tasks pertinent to nicotine addiction. Plasma nicotine and cotinine will be included as a factor in analyses of nicotine-induced effects on fMRI signal to take account of potentially large inter-individual variability in circulating nicotine concentrations. 