Using a monetary gambling task, Kamarajan et al. (2012) found that during the loss condition controls showed a single and stronger midline prefrontal source related to theta EROs around N2-P3 complex (200-500 ms), while alcoholics showed bilateral and weaker prefrontal sources. During the gain condition, controls had well-defined anterior and posterior sources while the alcoholics showed weaker and diffused sources (see Fig. 3). Although this study has not explicitly described how exactly the CSD was computed, as cited by the references in the Method section, we (the same authors) confirm that the CSD was computed using local polynomial approximations method proposed by Wang and Begleiter (1999). In this study, the authors found that the CSD topographic maps, in comparison to the activity patterns of the potential data, were more advantageous to interpret the activation patterns during loss and gain and to differentiate alcoholics from control group.
