Eyes Points, As The Movement Synthesis And Optokinetic Nystagmus (okn) Eye Movements

When moving gratings of different directions are presented separately to the two eyes, besides the perception of monocular motion and its corresponding OKN eye movement, the perception of the motion combination and the OKN in the direction of combined motion could be produced. We investigated whether such interocular motion combination is determined by the intersection-of-constraints (IOC) or vector average (VA) mechanism. According to the rule of IOC, the velocity of combined motion increases as the direction difference between the two motion signals increases. According to the rule of VA, the velocity of combined motion decreases. By examining the changes of the velocity of combined motion with the interocular motion direction difference, the mechanism underlies the motion combination could be testified. OKN eye movement is an objective indicator of the perceived motion, so we used OKN to quantitatively measure the velocity of combined motion. The results showed that the velocity of combined motion increases with direction difference. It suggests that the interocular motion combination in dichoptic gratings is determined by the IOC of two monocular moving gratings. Further we used the moving random dot patterns which lack the form information, to confirm whether the motion combination is related with the form information of moving stimuli. The results showed that both OKN eye movements and motion perception alternate only between the direction of the two monocular motions. Thus, the interoular motion combination in dichoptic moving stimuli might be derived from the motion of interocular combined pattern.