Dual role of nicotine in addiction and cognition: A review of neuroimaging studies in humans

► Nicotine has high addiction liability as well as cognition-enhancing effects. ► Elucidation of neurobiological mechanisms of nicotine is clinically important. ► Human PET, SPECT, and fMRI neuroimaging is used to study nicotine's actions in vivo. ► Receptor neuroimaging shows nicotine's effects on nAChRs and on DA system. ► Functional neuroimaging shows nicotine's complex effects on cognitive brain networks.