Alpha activity: The influence of unpatterned light input and auditory feedback

The electroencephalographic alpha activity was studied in ten nonpaid healthy volunteers of either sex, 24-to-27 years of age, under the following experimental conditions: in the dark, in the presence of light of various intensity (1-foot candle, 3-foot candle, and 15-foot candle), with and without alpha contingent auditory feedback. Subjects wore light-diffusing goggles that prevented patterned vision throughout the experimental session.The diffuse-light input was found to be devoid of any effect on alpha activity in the absence of auditory feedback. However, during the feedback, the light intensity above 1-foot candle had a significant suppressant effect on alpha activity. This phenomenon can be explained by an interaction between these two modalities. The 40-minute feedback training did not enhance the basic capacity of subjects to produce alpha activity above their own baseline level.