Average CRN and ERN amplitudes were assessed at electrode FCZ between 20 and 120 ms following the response, which is the time interval within which these potentials reached their peak. A significant effect of diagnosis was revealed for the amplitude of the CRN [F(1, 24) = 12.08; p = 0.002]; here, the alcoholic group generated larger negative amplitude potentials for all condition types (HsHr, HsLr, LsHr, and LsLr) than the control group. After correcting for years of education, no main effect of stimulus complexity or response congruency and no interactions between the factors were observed (p > 0.146). The results of the univariate analysis on the ERN showed a significant effect of diagnosis [F(1, 24) = 5.83; p = 0.024] such that alcoholics thus also developed larger negative ERN amplitudes following incorrect responses than the controls (Figs. 5, 6).
