EFFECTS OF PERIPHERAL FLICKER MASKING ON M-PATHWAY AND P-PATHWAY RESPONSE

Purpose: The effects of metahue and metacontrast masking on the respon ses of the M- and P-pathways of the human visual system were investiga ted using temporal analysis of the multifocal flash visually evoked po tential (VEP) (VERIS system). Methods: The experiments were carried ou t at three achromatic luminance contrasts, 24, 70 and 96%, with three peripheral masks: a steady 65% grey mask, a grey flicker mask and an i soluminant red/green flicker mask. The stimuli were viewed monocularly and the mask and VERIS stimuli superposed with a mirror-aperture syst em. Results/Conclusions: The masks had no significant effect on the be haviour of the M-pathway as stimulus contrast increased. The amplitude of the P-pathway was found to be approximately level at ail contrasts of the stimulus and with ail three masks rather than showing the expe cted steady increase in activity with increasing stimulus contrast.