Analysis of the effect of temporal frequency on the dichoptic visual-evoked response

When observers with normal binocularity view reversing black and white checkerboard patterns, the amplitude of the resulting binocular visual-evoked response (VER) is significantly greater than the amplitude of either corresponding monocular response. When the same checkerboard pattern is dichoptically presented with an interocular luminance difference (1.3 to 2.0 log units), the amplitude of the dichoptic VER is significantly less than either monocular response. In a previous study, we attributed this effect to interference between the monocular components of the binocular response resulting from a phase shift induced by the interocular luminance difference. To test this hypothesis, dichoptic VER's were recorded for three temporal frequencies (1.88, 3.75, and 7.5 Hz). The results obtained support the phase shift interpretation.