BIASES OF MOTION PERCEPTION REVEALED BY REVERSING GRATINGS IN HUMANS WHO HAD INFANTILE-ONSET STRABISMUS

Motion perception was tested by requiring adult subjects to view grati ngs that remained stationary but reversed in contrast several times pe r second. Subjects viewed monocularly and judged whether the gratings were stationary, or moving in one direction, in successive 3s trials. Subjects who had early-onset strabismus most frequently perceived vert ically oriented gratings to be moving nasalward, and horizontally orie nted gratings to be moving up or down. Normal subjects and subjects wh o had late-onset strabismus most frequently perceived the gratings to be stationary. The asymmetries of motion perception in early-onset str abismus imply that the visual motion neurons of cerebral cortex develo p properly only if they receive normal binocular input during infancy.