The major finding of the present study was that older male HR offspring and younger female HR offspring showed significantly lower P3 amplitudes during the loss condition. Although the present study is the first to report P3 deficits during reward processing in a monetary gambling paradigm in HR offspring, similar reward-related P3 deficits have been previously reported in alcoholics (Porjesz et al., 1987; Kamarajan et al., 2010) and their offspring (Ramsey and Finn, 1997). Since, reward related P3 amplitude has been found to be sensitive to both the valence (loss/gain) and magnitude (larger/smaller) of the outcomes (Toyomaki and Murohashi, 2005a; Kamarajan et al., 2009; Kamarajan et al., 2010), it can be taken as an index of reward processing. Hence, low P3 amplitudes manifested by HR offspring may represent dysfunctional or suboptimal reward processing.
