Time course and regional distribution of cortical changes during acute alcohol ingestion

Behavioral effects of alcohol are known to be greater when the blood alcohol is rising, known as the Mellanby effect; however, research investigating the cortical changes during this period is scarce. The objective of this study was to investigate the effects of consumption of alcohol on cortical activity measured by the electroencephalogram (EEG) during the absorption or rising phase of alcohol EEG signals were recorded using the entire 10/20 montage system. The experimental design consisted of a repeated measures randomized crossover design in which subjects acted as their own control. This involved recording two EEG baseline measures, each of which was followed by a placebo or alcohol condition, delivered over two days for ten subjects. All subjects had a 50% chance of receiving the alcohol first. All subjects were shown to have mean peak blood alcohol concentration (BAC) levels of around .03%. No significant differences were found between the two baselines. Significant increases in EEG magnitude occurred in the theta (4-7.75 Hz), alpha 1 (8-9.75 Hz), and beta 1 (13.25-19.75 Hz) spectrum in the frontal EEG regions, and alpha 1 (8-9.75 Hz) in the central and posterior regions. No significant changes were found in the theta (4-7.75 Hz) or beta (13.5-30 Hz) spectrums in the central and posterior regions. There were also no significant results for alpha 2 (10-13 Hz) in any of the regions. These results suggest that rapid cortical changes occur within the first 35 min after alcohol consumption.