The magnitude and dynamics of interocular suppression affected by monocular boundary contour and conflicting local features

A monocular boundary contour (MBC) rivalry stimulus has two half-images, a homogeneous grating and the same homogeneous grating with an additional disc region. The outline/frame of the MBC disc is created by relative phase-shift, or orientation-difference. We found the increment contrast threshold and reaction time to detect a monocular Gabor probe elevated on the homogeneous half-image pedestal. The interocular suppression begins as early as 80 ms upon stimulus onset. Moreover, the suppression magnitude is larger when the MBC disc is defined by orientation-difference rather than phase-shift, revealing the suppression caused by competing local features in addition to MBC.