Alcohol as well as other substances of abuse, including cocaine and cannabinoids, have been shown to have reinforcing properties. These substances influence mesolimbic dopamine transmission with acute activations of neurons in frontolimbic circuitry rich in dopamine, including the ventral striatum 97–99. As suggested by Hardin and Ernst (2009) 92, the use of these substances may exacerbate an already enhanced ventral striatum response resulting in heightened or strengthening of reinforcement properties to the drug. Robinson and Berridge 61, 63, 100 have suggested that these drugs of abuse can “hijack” the systems associated with drug incentives like the ventral striatum, thus down regulating top down prefrontal control regions.
