Visual, Spatial and Temporal Filtering and Hyperacuity

视敏度是衡量眼睛能够分辨非常 微小的目标，并受到大小和分布的限制 光感受器细胞。 然而，轻微的 在其它直线中侧向位移中断可以 当位移小于 比正常视力所能预测的要严重 这种可辨别性是 被称为超敏，可以通过这种刺激来证明 称为游标位移，或通过光栅的位移 图案或通过图案的二等分。 理解超敏 对于理解视觉信息处理是很重要的 因为超敏度揭示了视觉的终极精确度 空间定位。 该项目将研究如何空间和时间属性的 眼睛和大脑中的信息通道决定了 超敏的极限 单个神经元（神经细胞）， 视觉系统具有特殊的响应特性， 在时间上优先过滤特定频率 （周期/秒）或间隔（例如，光栅的周期/度）。 超敏目标或游标和光栅位移将被 呈现给人类观察者，然后这些目标将被 被闪烁照明的存在“掩盖”，或 叠加光栅或时空噪声。 的 将对这些不同情况的区别进行比较。 到 确定神经机制的动态特性 所涉及的将需要测量位移阈值， 亮度对比度、颜色对比度、平均值 亮度和时间频率。 最后，将比较 试图在人类超敏度表现和 猕猴单个神经元的超急性能力 猴子的视觉路径 这项工作的目标是全面了解 超敏的神经基础 方法结合 心理物理学，生理学和数学建模是罕见的， 强大. 理解这场精彩的表演， 神经机制将导致更好的理论基础， 理解视觉表现的极限。

Visual acuity is a measure of how well the eye can resolve very tiny targets, and is limited by the size and distribution of the photoreceoptor cells in the eye. However, a slight sideways displacement break in an otherwise straight line can be detected when the displacement is as much as five times less than the normal acuity would predict. This discriminability is known as hyperacuity, and can be demonstrated by this stimulus called vernier displacement, or by displacement of a grating pattern or by bisection of a pattern. Understanding hyperacuity is important for understanding visual information processing because hyperacuity reveals the ultimate precision of visual localization in space. This project will study how spatial and temporal properties of information channels in the eye and brain determine the limits of hyperacuity. Single neurons (nerve cells) in the visual system have particular response properties that preferentially filter particular frequencies in time (cycles/sec) or space (cycles/degree, of a grating, for example). Hyperacuity targets or vernier and grating displacement will be presented to human observers, and then these targets will be "masked" by the presence of flickering illumination, or superimposed gratings, or spatiotemporal noise. The discriminations will be compared for these different cases. To determine the dynamic characteristics of the neural mechanisms involved will require measurement of displacement thresholds as a function of luminance contrast, color contrast, mean luminance, and temporal frequency. Finally, a comparison will be attempted between human hyperacuity performance and the hyperacute capabilities of single neurons in the macaque monkey's visual pathway. The goal of this work is a comprehensive understanding of the neural basis for hyperacuity. The approach combining psychophysics, physiology and mathematical modelling is rare and powerful. Understanding this wonderful performance in terms of neural mechanisms will lead to a better theoretical basis for understanding the ultimate limits of visual performance.