Madelain Laurent, Krauzlis Richard J
Systems Neurobiology Lab, Salk Institute for Biological Studies, La Jolla, CA, USA.
J Vis. 2003 Nov 18;3(11):642-53. doi: 10.1167/3.11.1.
Pursuit can be guided by perceived rather than physical motion, but the temporal relationship between motion perception and pursuit is unknown. We used an apparent motion stimulus consisting of a horizontal row of evenly spaced Kanizsa illusory squares (1.44 deg2): the illusory contours appeared at the midpoints of the illusory squares presented in the previous frame, producing bi-directional apparent motion of the illusory contours (21.5 deg/s) that could be reversed at will. We measured eye movements in five subjects asked to (1) track the motion of the illusory squares, and (2) reverse the perceived direction while continuing to track the squares. We measured the timing of the voluntary perceptual reversals and compared this to the time course of the reversal in tracking direction. We found that subjects could smoothly track the apparent motion of illusory squares and also produce saccade-free reversals in pursuit velocity. The time course of these motor reversals closely followed the measurements of the perceptual reversal and, on average, the perceptual reversals preceded the pursuit reversals by 53 ms, a delay shorter than when the perceptual reversal was visually guided. Smooth pursuit and the perception of motion direction were in temporal register and highly correlated, suggesting that pursuit can provide a real-time readout for the state of motion perception.
追踪可以由感知到的运动而非实际运动引导，但运动感知与追踪之间的时间关系尚不清楚。我们使用了一种表观运动刺激，它由一排水平排列、间距均匀的卡尼萨错觉方块组成（面积为1.44平方度）：错觉轮廓出现在前一帧中呈现的错觉方块的中点处，产生错觉轮廓的双向表观运动（速度为21.5度/秒），且可随意反转。我们测量了五名受试者的眼球运动，要求他们：（1）追踪错觉方块的运动，（2）在继续追踪方块的同时反转感知到的方向。我们测量了自愿性感知反转的时间，并将其与追踪方向反转的时间进程进行比较。我们发现，受试者能够顺利追踪错觉方块的表观运动，并且在追踪速度上也能实现无扫视的反转。这些运动反转的时间进程紧密跟随感知反转的测量结果，平均而言，感知反转比追踪反转提前53毫秒，这一延迟比视觉引导感知反转时要短。平稳追踪与运动方向感知在时间上是同步的，且高度相关，这表明追踪可以为运动感知状态提供实时读数。
