In their first ERO study of animal models of alcoholism, Criado and Ehlers [170] investigated the utility of EROs as effective risk markers by using genetic mouse models of high alcohol preference. The authors measured delta, theta and alpha/beta ERO energy and the degree of phase variation in groups of high and low alcohol preferring mice and found that the decreased P3 amplitudes previously shown in B6 mice (with a low level of withdrawal severity), compared to D2 mice (with extreme withdrawal severity) [169], was related to reductions in evoked delta ERO energy and delta and theta phase locking. In contrast, the increase in P1 amplitudes reported in HAP mice, compared to LAP mice, is associated with increases in evoked theta ERO energy. Further, these differences in delta and theta ERO measures in mice mirrored the changes observed in human subjects between high and low risk for alcoholism where changes in EROs were found to be more significant than group differences in P3 amplitudes. Based on these findings, the authors suggested that ERO these measures are more stable endophenotypes in the study of alcohol dependence than P3.
