The effects of spatial frequency adaptation on human evoked potentials

The spatial frequency selectivity of the adaptation to gratings in man has been verified with the technique of evoked potentials. The amplitude of the potentials evoked by a low contrast grating is reduced after the adaptation to a high contrast grating of the same spatial frequency and orientation. The effect is maximum for the adapting frequency and extends to other frequencies enclosed within about two octaves. Differences have been found between evoked potentials and contrast threshold for what regards the width of the channel affected and the recovery after the adaptation.