Despite an increased understanding of the long-term cognitive effects of nicotine, little research to date has examined its chronic effects upon reward processing in the brain. The reward deficiency syndrome of addiction posits that there are deficits in dopamine motivational circuitry for non-drug rewards, such that only drugs of abuse are capable of normalizing dopamine at the ventral striatum (VS). This proposal, relating the long-term effects of drugs to a hypodopaminergic state, is particularly relevant to reward processing in nicotine addiction, given existing evidence for long-lasting reductions in striatal dopamine D2 receptors in smokers. Therefore, examining changes in reward-related brain functioning for non-drug rewards in current cigarette smokers may reveal alterations within neural circuitry which contribute to nicotine addiction. Importantly, examining the effects of previous, long-term nicotine exposure upon reward processing, during long-term smoking abstinence, may elucidate neural reward mechanisms which have been persistently compromised by chronic nicotine use. To this end, the current study will examine neural reward functioning in smokers, ex-smokers and non-smokers while they perform a monetary incentive delay (MID) task during functional MRI.