Visual Motion And The Stabilization Of Gaze

视觉运动和注视的稳定性

基本信息

批准号：
7734586
负责人：
FREDERICK A. MILES
金额：
$ 74.39万
依托单位：
NATIONAL EYE INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

项目摘要

Ocular following responses (OFRs) are the initial tracking eye movements that can be elicited at ultra-short latency by sudden motion of a textured pattern. We recently used motion stimuli consisting of two large coextensive sine-wave gratings with the same orientation but different spatial frequency and moving in -wavelength steps in the same or opposite directions: we found that when the two gratings differed in contrast by more than about an octave then the one with the higher contrast completely dominated the OFR and the one with lower contrast lost its influence as though suppressed. We attributed this winner-take-all (WTA) outcome to nonlinear interactions in the form of mutual inhibition between the mechanisms sensing the competing motions. In the present study, we recorded the initial horizontal OFRs to the horizontal motion of two vertical sine-wave gratings that differed in spatial frequency and were each confined to horizontal strips that extended the full width of our display (45) but were only 1-2 high. The two gratings could be coextensive or separated by a vertical gap of up to 8, and each underwent motion consisting of successive -wavelength steps. Initial OFRs showed strong dependence on the relative contrasts of the competing gratings and when these were coextensive this dependence was always highly nonlinear (WTA), regardless of whether the two gratings moved in the same or opposite direction. When the two gratings moved in opposite directions the nonlinear interactions were purely local: with a vertical gap of 1 or more between the gratings OFRs approximated the linear sum of the responses to each grating alone. On the other hand, when the two gratings moved in the same direction the nonlinear interactions were more global: even with a gap of 8the largest separation triedOFRs were still substantially less than predicted by the linear sum. When the motions were in the same direction, we postulate two nonlinear interactions: local mutual inhibition (resulting in WTA) and global divisive inhibition (resulting in normalization). Motion stimuli whose responses were totally suppressed by coextensive opponent motion of higher contrast were rendered invisible to normalization, suggesting that the local interactions responsible for the WTA behavior here occur at an earlier stage of neural processing than the global interactions responsible for normalization.

眼后反应（OFRS）是最初的跟踪眼运动，可以通过纹理模式的突然运动在超短期潜伏期中引起。最近，我们使用了运动刺激，包括两个大型的正弦波光栅，具有相同的方向但空间频率不同，并且以相同或相反的方向移动 - 波长步骤：当两个光栅的对比度差异时，相对于八度的差异更大，而与较高对比的八度差异更大，而具有较高的对比的人会完全统治着对比，并且对对比度的影响较低。我们将这种赢家全部（WTA）结果归因于非线性相互作用，以感知竞争动作的机制之间相互抑制的形式。在本研究中，我们将初始水平的OFRS记录到两个垂直正弦光栅的水平运动，它们在空间频率上有所不同，每个光栅都局限于延长显示屏宽度的水平条（45），但仅1-2高。这两个光栅可以通过高达8的垂直缝隙共同扩展或分离，每个光栅都通过连续波长的步骤进行运动。最初的OFRS表现出强烈的依赖性对竞争光栅的相对对比度，而当它们共同扩展时，这种依赖性始终是高度非线性（WTA），而不管两个光栅是朝着相同还是相反的方向移动的。当两个光栅朝相反的方向移动时，非线性相互作用纯粹是局部的：在RRS的光栅之间，垂直差距为1或更多，近似于单独使用每个光栅的响应的线性总和。另一方面，当两个光栅朝着相同的方向移动时，非线性相互作用更具全球性：即使有8个最大分离的差距，尝试的距离仍然大大低于线性总和所预测的。当运动朝着相同的方向时，我们假设两种非线性相互作用：局部互抑制（导致WTA）和全局分裂性抑制（导致归一化）。具有较高对比的共同对手运动完全抑制了反应的运动刺激，这是不可见的，这表明，与负归一化的全球相互作用相比，在神经处理的早期阶段，负责WTA行为的局部相互作用发生。