Consistent with the present results, we recently showed that reductions in evoked delta phase locking in the parietal cortex are related to the decrease in P3 amplitudes in high ethanol preference C57BL/6 (B6) mice, compared to low ethanol preference DBA/2J (D2) mice (Criado and Ehlers, 2009). This previous study also demonstrated that reductions in evoked delta ERO energy and theta phase locking in the parietal cortex are associated with a decrease in P3 amplitudes in B6 mice (Criado and Ehlers, 2009). In contrast, the present study found that differences in ERO energy between P and NP rats do not play an important role in the decrease in P3 amplitudes found in P rats. These findings indicate that reduced P3 amplitudes in rat models of high ethanol preference may have different neurophysiological profiles than humans. These data also suggest different neurophysiological mechanisms associated with a reduction of P3 amplitudes in rat and mouse models of high ethanol preference (Ehlers et al., 1999; Ehlers and Somes, 2002; Slawecki et al., 2003).
