Acoustic stimulus threshold related to EEG alpha and non-alpha epochs

In humans sitting in the dark with their eyes closed the presence of EEG alpha and non-alpha epochs was registered automatically and the threshold detection of weak acoustic stimuli and reaction time of responses were measured according to the principles of the von Békésy audiometer under both conditions. The threshold was higher during alpha epochs in comparison with non-alpha ones. The reaction time of responses under both conditions was equal. Presentation of the stimulus did not influence the duration of corresponding alpha or non-alpha epochs significantly.