Brain imaging studies to assess DA responses to conditioned cues have shown that active cocaine abusers exhibit significant DA increases in the striatum when they are exposed to videos depicting scenes of individuals procuring and administering cocaine. In addition, the magnitude of this increase was correlated with the subjective experience of craving (32, 33). Cocaine abusers with the largest cue-induced DA increases in the dorsal striatum also scored higher on addiction severity, thereby suggesting that a basic disruption in addiction may be enhanced reactivity of DA mesostriatal pathways to conditioned responses. The dorsal striatum is implicated in habit learning; thus, its engagement with cue exposures is likely to reflect the strengthening of habits as chronicity of addiction progresses.
