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：
7594040
负责人：
FREDERICK A. MILES
金额：
$ 90.87万
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

Radial optic flow applied to large random dot patterns is known to elicit horizontal vergence eye movements at short latency, expansion causing convergence and contraction causing divergence: the Radial Flow Vergence Response (RFVR). We elicited RFVRs in human subjects by applying radial motion to concentric circular patterns whose radial luminance modulation was that of a square wave lacking the fundamental: the missing fundamental (mf) stimulus. The radial motion consisted of successive quarterwavelength steps, so that the overall pattern and the 4n+1 harmonics (where n=integer) underwent radial expansion (or contraction), whereas the 4n-1 harmonicsincluding the strongest Fourier component (the 3rd harmonic)underwent the opposite radial motion. Radial motion commenced only after the subject had fixated the center of the pattern. The initial RFVRs were always in the direction of the 3rd harmonic, e.g., expansion of the mf pattern causing divergence. Thus, the earliest RFVRs were strongly dependent on the motion of the major Fourier component, consistent with early spatio-temporal filtering prior to motion detection, as in the well-known energy model of motion analysis. If the radial mf stimulus was reduced to just two competing harmonicsthe 3rd and 5ththe initial RFVRs showed a nonlinear dependence on their relative contrasts: when the two harmonics differed in contrast by more than about an octave then the one with the higher contrast completely dominated the RFVRs and the one with lower contrast lost its influence: winner-take-all. We suggest that these nonlinear interactions result from mutual inhibition between the mechanisms sensing the motion of the different competing harmonics. If single radial-flow steps were used, a brief inter-stimulus interval resulted in reversed RFVRs, consistent with the idea that the motion detectors mediating these responses receive a visual input whose temporal impulse response function is strongly biphasic. Lastly, all of these characteristics of the RFVR, which we attribute to the early cortical processing of visual motion, are known to be shared by the Ocular Following Response (OFR)a conjugate tracking (version) response elicited at short-latency by linear motionand even the quantitative details are generally very similar. Thus, although the RFVR and OFR respond to very different patterns of global motionradial vs. linearthey have very similar local spatiotemporal properties as though mediated by the same low-level, local-motion detectors, which we suggest are in the striate cortex.

已知应用于大型随机点模式的径向光流可以在短潜伏期下引起水平的眼球运动，从而膨胀，导致收敛和收缩引起发散：径向流动性响应（RFVR）。我们通过将径向运动应用于径向亮度调制的同心圆形图案中，从而引起了人类受试者的RFVR，其radial圆形模式是缺乏基本的平方波：缺失的基本（MF）刺激。径向运动由连续的四分之一波长步骤组成，因此总体模式和4N+1谐波（其中n =整数）进行了径向膨胀（或收缩），而4N-1谐波（包括最强的傅立叶成分（第三谐））进行了相反的辐射运动。径向运动仅在受试者固定模式中心后才开始。初始RFVR始终朝着第三谐波的方向，例如，MF模式的扩展导致发散。因此，最早的RFVR强烈依赖于主要的傅立叶成分的运动，与早期的时空滤波在运动检测之前，如众所周知的运动分析能量模型。 If the radial mf stimulus was reduced to just two competing harmonicsthe 3rd and 5ththe initial RFVRs showed a nonlinear dependence on their relative contrasts: when the two harmonics differed in contrast by more than about an octave then the one with the higher contrast completely dominated the RFVRs and the one with lower contrast lost its influence: winner-take-all.我们建议这些非线性相互作用是由于感应不同竞争谐波运动的机制之间的相互抑制而引起的。如果使用了单个径向流量步骤，则简短的刺激间隔会导致RFVR相反，这与介导这些响应的运动检测器获得的视觉输入的想法一致，其时间脉冲响应函数强烈双重响应。最后，我们将RFVR的所有这些特征归因于视觉运动的早期皮质处理，它们是由眼部后响应（OFR）共享的共轭跟踪（版本）响应是由线性运动以短期延迟引起的，甚至定量细节通常非常相似。因此，尽管RFVR和OFR响应了非常不同的全局运动模式与线性的模式，但局部时空特性非常相似，好像是由相同的低级局部运动探测器介导的，我们认为这是在条纹皮质中。