Activation of reward circuitry in human opiate addicts

The neurobiological mechanisms of opiate addictive behaviour in humans are unknown. A proposed model of addiction implicates ascending brainstem neuro modulatory systems, particularly dopamine. Using functional neuroimaging, w e assessed the neural response to heroin and heroin-related cues in establi shed opiate addicts. We show that the effect of both heroin and heroin-rela ted visual cues are maximally expressed in the sites of origin of ascending midbrain neuromodulatory systems. These context-specific midbrain activati ons predict responses to salient visual cues in cortical and subcortical re gions implicated in reward-related behaviour. These findings implicate comm on neurobiological processes underlying drug and drug-cue-related effects.