A typical gambling task involves ‘choice’ stimuli (for which the subjects have to choose one of two or more choices to bet with) and ‘outcome’ or ‘feedback’ stimuli which show the resultant outcome (e.g., loss or gain) for the choice made during a particular trial [148]. Alcoholics have been reported to have deficient ERP components obtained from gambling tasks [11,149]. However, to our knowledge, only one ERO study has used a gambling paradigm in alcoholics; Kamarajan et al. [150] examined the relationship among the factors of ERO measures, impulsivity, and alcoholism. In this study, ERO theta power in the time window of 200-500 ms (wherein the ‘outcome-related’ ERP negativity and positivity occur) was compared across alcoholic and control groups (Figure 1). The subjects in the study 1) were asked to select one of two amounts (10¢ or 50¢) to bet with, and 2) received feedback/outcome about the selected amount (i.e., Loss 10, Loss 50, Gain 10, and Gain 50). The alcoholic group showed significantly decreased theta power during reward/outcome processing compared to controls. A strong association between reduced anterior theta
