The STN’s influence may have relevance to substance use through regulation of behavior. Animals with STN lesions exhibit increased impulsive action, decreased impulsive choice (Uslaner and Robinson, 2006) and changes in motivation (Baunez et al., 2005, Winstanley et al., 2005). The lesion-induced changes increased motivation for natural (food) rewards and reduced motivation for drug (cocaine) rewards suggesting influence on incentive salience. Further, in ‘high-drinker’ rats, STN lesions enhanced motivation for alcohol but further decreased it in ‘low-drinker’ rats, suggesting a role involving motivation and individual preference (Lardeux and Baunez, 2007) with the authors proposing the STN as a target for treatment of addiction (Baunez et al., 2005). Again, Parkinson’s patients provide complementary information; STN stimulation, combined with reduction in dopaminergic treatment, has decreased pathological gambling (Ardouin et al., 2006, Bandini et al., 2007) and addiction (Witjas et al., 2005) in patients.
