Brain imaging studies have monitored the shifts in regional brain activity of addicted persons when exposed to drug-conditioned cues versus when exposed to non-drug-related cues. When studied without exposure to drug stimuli, substance abusers showed significant decreases in activity of prefrontal regions implicated in motivation including the orbitofrontal cortex and ACC (reviewed in Reference 19). In contrast, these prefrontal regions become activated when drug abusers were exposed to drug-related stimuli (39, 68–70). Similarly, cocaine abusers studied shortly after an episode of cocaine binging showed increased metabolic activity in the orbitofrontal cortex and ACC (as well as the dorsal striatum), which was associated with drug craving (71).
