Taken together, these studies of cigarette craving indicate that immediate responses to visual smoking-related cues (fMRI study) activate the brain reward system, limbic regions, and the visual processing system, while longer exposure to cues (FDG–PET study) leads to activation of the ACC, which mediates anxiety, alertness, and arousal (Chua et al. 1999; Critchley et al. 2001; Kimbrell et al. 1999; Naito et al. 2000; Rauch et al. 1999) and the OFC, which functions in part as a secondary processing center for sensory information (Rolls et al. 1998; Rolls and Baylis 1994).
