Dose-dependent suppression by ethanol of transient auditory 40-Hz response

Rationale: Acute alcohol (ethanol) challenge is known to induce various cog nitive disturbances, yet the neural basis of the effect is poorly known. Th e auditory transient evoked gamma-band (40-Hz) oscillatory responses have b een suggested to be associated with various perceptual and cognitive functi ons in humans; however, alcohol effects on auditory 40-Hz responses have no t been investigated to date. Objectives: The objective of the study was to test the dose-related impact of alcohol on auditory transient evoked 40-Hz responses during a selective-attention task. Methods: Ten healthy social dr inkers ingested, in four separate sessions, 0.00, 0.25, 0.50, or 0.75 g/kg of 10% (v/v) alcohol solution. The order of the sessions was randomized and a double-blind procedure was employed. During a selective attention task, 300-Hz standard and 330-Hz deviant tones were presented to the left ear, an d 1000-Hz standards and 1100-Hz deviants to the right ear of the subjects ( P=0.425 for each standard, P=0.075 for each deviant). The subjects attended to a designated ear, and were to detect the deviants therein while ignorin g tones to the other ear. Results: The auditory transient evoked 40-Hz resp onses elicited by both the attended and unattended standard tones were sign ificantly suppressed by the 0.50 and 0.75 g/kg alcohol doses. Conclusions: Alcohol suppresses auditory transient evoked 40-Hz oscillations already wit h moderate blood alcohol concentrations. Given the putative role of gamma-b and oscillations in cognition, this finding could be associated with certai n alcohol-induced cognitive deficits.