Interocular suppression weakens binocular disparity integration in the dorsal visual stream

Abstract A unified percept depends on the coordinated interplay of sensory integration and suppression, yet how this interaction is implemented across cortical representations remains unclear. Using binocular vision as a tractable model system, we combined fMRI with multivariate analyses to test how interocular suppression reshapes binocular disparity integration across human visual pathways. Local binocular rivalry weakened near–far disparity decoding, with disruption increasing along the dorsal pathway from V1 to V3A and intraparietal sulcus (IPS), but no reliable loss in ventral regions. In V3A, anticorrelated random-dot stereograms showed an inverted representational relationship relative to correlated stimuli, and this structure was abolished under suppression, indicating disrupted non-canonical disparity integration. Informational connectivity further revealed that suppression selectively weakened V3A-centered coordination while largely sparing coupling among early visual areas. Together, these findings identify higher-level dorsal regions as a key substrate for coordinating integrative and suppressive computations during unified percept formation.