the OFC that may contribute to the persistence of addictive disorders. The dysfunction in delayed discounting reward tests involves learning initial rewards and continually assessing outcomes to improve results. This requires a form of relearning that initial learned rewards can be delayed for bigger rewards. Alcoholics have difficulty with these tasks. Interestingly, we have found that the non-selective opioid antagonist naltrexone (NTX), one of few drugs approved to treat alcoholism in the U.S., significantly elevates activity in the OFC during decision-making (Fig. 2) (Boettiger et al., in press). Moreover, the effect of NTX on OFC activity predicted the effect of NTX on decision-making (Boettiger et al., in press). These results suggest that a therapeutic action of NTX may be to support the long-term decision-making critical to recovery from alcoholism by increasing activity in the OFC. It is likely that frontal cortical dysfunction contributes to the impulsive-compulsive aspects of addictive behaviour and effective addiction therapies may reverse frontal cortical dysfunction.
