Enhanced dorsolateral striatal activity in drug use: The role of outcome in stimulus-response associations

Prolonged stimulant exposure leads to enhanced dorsolateral striatal (DLS) dopaminergic activity in response to the drug and drug-associated cues. This effect has been interpreted in light of evidence that this brain region supports the generation of habitual stimulus-response (S-R) based behaviors to propose the idea that prolonged drug use leads to the development of drug taking and seeking habits that are insensitive to the value of the rewards they procure. In this review, we discuss evidence supporting a continued role for reward value in the performance of S-R based behaviors. We describe how caching of reward value and Pavlovian to instrumental transfer can provide mechanisms for past and current reward values to regulate the performance of S-R habits. The contribution of these constructs is consistent with evidence indicating the continued interaction between ventral incentive processing and dorsal S-R processing striatal regions in the generation of habitual drug seeking behaviors. (C) 2012 Elsevier B.V. All rights reserved.