The spatial properties of binocular suppression zone.

Spatial properties of binocular suppression zones were studied with one-dimensional difference of Gaussian (DOG) patterns. Two parallel DOG patterns were presented in one eye and a single DOG, perpendicular to the double DOG, was presented to the other eye. When viewed together, the probability of seeing the portion of the single DOG in between of the double DOG depended on the separation of the double DOG stimulus. Threshold separations for detecting an intermediate segment of the single DOG pattern (binocular suppression zones) were measured as a function of spatial frequency, contrast and orientation of the stimuli. The diameter of suppression zone decreased proportionally with increasing peak spatial frequency of the DOG patterns. The vertical dimension of the suppression zone was larger than the horizontal dimension at low spatial frequencies but the inverse tended to occur at high spatial frequencies. Diameter of the suppression zone increased rapidly with increasing contrast of the stimuli when the contrast was lower than 20-30% but asymptoted at higher contrasts.