QUANTITATIVE STUDIES OF VISUAL PATHWAYS

这里提出的工作的总体目标是了解如何中央 视觉通路分析有关色彩和空间的信息， 对象的属性。 提出了三个主要项目。 通过 结合生理和心理物理实验，这些尝试 为了阐明视觉的一个特定方面与其 潜在的生理学 第一个项目将探讨的可能性， 在猕猴P细胞感受野中，LGN的产生不是通过选择 但是通过中心接收来自单个锥体的输入， 环绕不加区别地绘制来自L和M视锥的输入。 生理测量将使用适当的干涉条纹。 颜色来分析视锥细胞输入在感受野中的组织， 不同偏心率的P细胞。 心理物理实验来估计 色彩对立机制对图像进行采样的密度 将探讨的必然结果是，缺乏侏儒P细胞在 我们的色觉受损的原因 第二个项目将使用沉默替代方法来研究如何 单个视锥细胞通路中的增益控制机制与 噪声来控制P细胞中的色彩灵敏度。 从事的工作内容 前一时期的支持显示了矛盾的变化， 背景色度变化后的P细胞反应，并显示 噪声的变化与这些相互作用， 刺激。 因为背景色度的变化也导致了长- 持久的变化，维持放电的P细胞，该项目还将 研究皮层神经元如何表达这些变化。 第三个项目将探讨的想法，神经元的行为，在 视觉皮层的早期阶段解释了知觉的独特性， 视觉纹理。 这些实验将研究神经元（特别是 V1和V2中的复杂细胞）对V1和V2中采用的类型的视觉纹理做出反应。 心理物理学研究 上一个报告期开展的工作 支持表明，更全面地了解皮质的作用， 细胞将需要使用视觉刺激， 他们的行为。 纹理识别的研究应该直接从 这是因为对纹理的知觉辨别似乎需要 非线性机制与复杂细胞中发现的特性相似。

The overall aim of the work proposed here is to understand how central visual pathways analyze information about the chromatic and spatial properties of objects. Three major projects are proposed. Through a combination of physiological and psychophysical experiments these attempt to elucidate the connection between a particular aspect of vision and its underlying physiology. The first project will explore the possibility that the chromatic opponency in receptive fields of P-cells of macaque LGN arises not through selection of cone classes, but through the center receiving input from a single cone, with the surround drawing indiscriminately on inputs from L and M cones. The physiological measurements will use interference fringes of appropriate color to analyze the organization of cone inputs in the receptive fields of P-cells at various eccentricities. Psychophysical experiments to estimate the density with which chromatically opponent mechanisms sample the image will explore the corollary that a paucity of midget P-cells in the periphery accounts for our impaired color vision. The second project will use silent-substitution methods to examine how gain-controlling mechanisms in individual cone pathways act together with noise to control chromatic sensitivity in P-cells. Work undertaken during the previous period of support revealed paradoxical changes in the gain of P-cell responses following changes in background chromaticity, and showed that changes in noise interact with these in regulating detectability of stimuli. Because changes in background chromaticity also led to long- lasting changes in maintained discharge of P-cells, the project will also examine how these changes are expressed by cortical neurons. The third project will explore the idea that the behavior of neurons in the early stages of visual cortex accounts for the perceptual distinctiveness of visual textures. The experiments will examine how neurons (particularly complex cells) in V1 and V2 respond to visual textures of types employed in psychophysical studies. Work undertaken during the previous period of support suggested that a fuller understanding of the roles of cortical cells will require the use of visual stimuli that tap the nonlinear aspects of their behavior. The study of texture discrimination should get directly at this because perceptual discrimination of textures appears to require nonlinear mechanisms with properties like those found in complex cells.