School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK.
Department of Psychology, Stanford University, Stanford, USA.
Sci Rep. 2019 Nov 22;9(1):17412. doi: 10.1038/s41598-019-53902-y.
When we track an object moving in depth, our eyes rotate in opposite directions. This type of "disjunctive" eye movement is called horizontal vergence. The sensory control signals for vergence arise from multiple visual cues, two of which, changing binocular disparity (CD) and inter-ocular velocity differences (IOVD), are specifically binocular. While it is well known that the CD cue triggers horizontal vergence eye movements, the role of the IOVD cue has only recently been explored. To better understand the relative contribution of CD and IOVD cues in driving horizontal vergence, we recorded vergence eye movements from ten observers in response to four types of stimuli that isolated or combined the two cues to motion-in-depth, using stimulus conditions and CD/IOVD stimuli typical of behavioural motion-in-depth experiments. An analysis of the slopes of the vergence traces and the consistency of the directions of vergence and stimulus movements showed that under our conditions IOVD cues provided very little input to vergence mechanisms. The eye movements that did occur coinciding with the presentation of IOVD stimuli were likely not a response to stimulus motion, but a phoria initiated by the absence of a disparity signal.
当我们追踪深度移动的物体时，我们的眼睛会朝相反的方向转动。这种“分离”的眼球运动被称为水平聚散。聚散的感觉控制信号来自多个视觉线索，其中两个线索是双眼视差（CD）和眼间速度差（IOVD），它们是专门用于双眼的。虽然众所周知，CD 线索会引发水平聚散眼球运动，但 IOVD 线索的作用直到最近才被探索。为了更好地理解 CD 和 IOVD 线索在驱动水平聚散中的相对贡献，我们记录了十个观察者的聚散眼球运动，这些运动是对四种刺激类型的反应，这些刺激类型将两种线索隔离或组合在一起，用于运动深度的刺激条件和 CD/IOVD 刺激与行为运动深度实验中的典型条件一致。对聚散轨迹斜率和聚散运动方向的一致性的分析表明，在我们的条件下，IOVD 线索对聚散机制几乎没有输入。与 IOVD 刺激同时发生的眼球运动可能不是对刺激运动的反应，而是由于缺乏视差信号而引发的隐斜视。
