Several studies have examined the effects of alcohol on cognitive processing in the auditory modality. The dose-related impact of alcohol on auditory transient evoked 40-Hz responses during a selective attention task was investigated; higher doses of alcohol significantly suppressed the early evoked gamma responses in both attended and non-attended conditions, suggesting cognitive impairment or lack of sensory binding (Jaaskelainen et al., 2000). Administration of alcohol was shown to decrease early synchronization during auditory encoding and increase later desynchronization in theta (4–6 Hz), low alpha (6–8 Hz), and high alpha (8–10 Hz) bands (Krause et al., 2002). This indicates that alcohol has disorganizing effects on the brain’s electric oscillatory systems in theta and lower alpha frequency ranges during cognitive processing. Similarly, disorganizing effects of alcohol on phase synchronization of EROs during an auditory oddball task were recently reported in humans and rats (Ehlers et al., 2012). They demonstrated reduced synchrony within and between neuronal networks with ethanol, perhaps by increasing the level of noise in key interactions; reduced alpha-phase synchrony was also correlated with blood alcohol level.
