Disparity Processing in Sensory and Motor Functions

追溯到154年前惠斯通的传统理论认为，立体深度知觉是由左眼和右眼视网膜图像之间的差异(视网膜差异)在视觉皮质早期刺激的。或者，立体视觉和双眼运动可以通过两个眼睛图像感知方向之间的双眼差异(以头部为中心的差异)在大脑的感觉运动区受到刺激。这些感知的方向是视网膜图像位置和眼睛位置信息的组合。在正常的视觉条件下，视网膜视差和头部中心视差是无法区分的，因此不可能确定哪种立体视觉是基于哪一种立体视觉。然而，当短暂闪光的目标在快速眼动(扫视)开始时出现较小的眼间时间延迟时，这两种形式的视差确实具有不同的大小。眼跳导致两只眼睛对感知方向的不同扭曲，这些差异产生了立体深度。这是第一个证据表明，眼球运动可以影响立体视觉的双眼视差刺激，并且双眼视差是以头心坐标表示的。在国家科学基金会的支持下，Schor博士将研究快速(扫视)眼睛运动如何导致立体深度知觉的扭曲。这些深度扭曲揭示了大脑如何表现出刺激立体视觉和双眼运动的双眼差异。除了提高我们对立体视觉的基本理解外，这项工作还涉及到眼睛运动可能如何影响计算机模拟立体显示器刺激的深度的准确性，计算机模拟立体显示器向两只眼睛的每一只眼睛呈现交替的帧。由此产生的空间扭曲可能会影响深度定位和瞄准任务的表现。

Traditional theories going back 154 years to Wheatstone propose that stereoscopic depth perception is stimulated early in the visual cortex by disparities between the retinal images on the left and right eyes (retinal disparity). Alternatively, stereopsis and binocular eye movements could be stimulated in sensory-motor regions of the brain by binocular disparities between perceived directions of the two ocular images (head-centric disparity). These perceived directions result from a combination of retinal image location and eye position information. Under normal viewing conditions, retinal disparities are indistinguishable from headcentric disparities, so it is not possible to determine which stereoscopic vision is based on. However, the two forms of disparity do have different magnitudes when a briefly flashed target is presented with a small interocular time delay near the onset of a rapid eye-movement (saccade). The saccade causes unequal distortions of perceived direction by the two eyes, and these differences produce stereo-depth. This is the first evidence that eye movements can influence binocular disparity stimuli for stereopsis and that binocular disparity is represented in headcentric coordinates.With support of the National Science Foundation, Dr. Schor will investigate how rapid (saccadic) eye movements produce distortions of stereoscopic-depth perception. These depth distortions reveal how the brain represents binocular disparities that stimulate stereopsis and binocular eye movements. In addition to improving our basic understanding of stereopsis, this work has implications concerning how eye movements might influence the accuracy of depth stimulated by computer-simulated stereo displays that present alternate frames to each of the two eyes. The resulting distortions of space could influence performance in depth localization and aiming tasks.