The Effect of Oculomotor Activity on Alpha‐Blocking in the Absence of Visual Stimuli

Abstract

ABSTRACTOne within‐subjects experiment employing 20 normal adults was performed to examine the effect of controlled eye movements in the dark on occipital KEG alpha. The subjects moved their open eyes laterally toward tones coming from 5 different loud speakers on a perimeter, in the dark. The amount of alpha recorded from each subject during his eye movements locating the auditory stimulus was compared with the amount of alpha recorded during the control condition of eyes open in the dark with tones coming from the perimeter of speakers, but with no eye movements. Visual input remained constantly zero during both conditions. Significantly more alpha‐blocking occurred during the eye movement condition than during the no eye movement control condition (rejection region =.95). Subsequent tests supported this finding for each of the 5 eye and loudspeaker positions. The results indicate that a visual stimulus is not necessary to produce suppression of alpha, but that controlled oculomotor adjustments are sufficient.