Our study used the same auditory stimuli in both rats and humans in order to investigate the phase variability of EROs following alcohol administration. Phase locking was significantly higher in the delta frequencies in humans than in rats. Phase locking was also higher for the rare (target) tone than the frequent (non-target) tone in both species. Significant reductions in phase locking to the rare (target) tone in the delta, theta, alpha, beta and gamma frequencies, within and between brain sites, was found at one hour following ethanol as compared to placebo/saline administration in both rats and humans. Increases in phase locking in the beta frequencies in frontal cortex were found to correlate significantly with the human participants overall ratings of their level of intoxication; whereas, reductions in phase locking in the alpha frequencies in the parietal cortex was found to be correlated with blood ethanol concentrations. These findings are consistent with the hypothesis that ethanol’s actions in the brain include reducing synchrony within and between neuronal networks, perhaps by increasing the level of noise in key neuromolecular interactions.
