PARALLEL PATHWAYS IN PRIMATE VISUAL CORTEX

现在有大量的证据表明， 通过灵长类动物的纹状体和 纹外视皮层 这些途径被标记为 “运动”和“颜色和形式”途径，表明一个详细的 了解它们各自的功能和相互作用。 然而，在这方面， 到目前为止，几乎没有直接证据表明这些作用 通路在视觉感知中发挥作用，或者它们的严格 独立 这里提出的研究旨在确定功能 这些独立的通路在灵长类动物中的作用， 因其中一方或另一方受到损害而造成的损失。 的 在一项研究中，“运动”通路将被 皮质区V2，这将中断一个主要的投射， 在以后的研究中，通过MT和/或MST的失活。 “颜色和形式”通路将在早期阶段受损， 其皮质路径由V2区的病变，并在一个单独的 实验，通过V4区本身的病变。 将产生病变 通过将鹅膏蕈氨酸局部注射到视野特异性 通过生理映射确定的区域。 视觉阈值 然后将在视野中的受控注视期间进行测试 与这些注射相对应的位置。1.第一组 的研究将评估V2病变对视力的影响， 颜色和运动感知的基本能力。 视觉 敏锐度、亮度和色彩对比敏感度、色彩 匹配，速度和方向差阈值将被 测定了 2.第二组研究将审查 视觉区域V4在处理颜色信息中的作用。 是 预计这一地区的删除应扰乱更高的水平， 而不是简单的颜色感知。 这一假设将是 通过测试两种基本能力（亮度和色度）来评估 对比敏感度）和更复杂的能力（颜色匹配） 在对应于病变的视野轨迹内。3.一 第三组研究将检查视觉损害的影响， MT和MST区对视觉运动的感知。 又是两个 基本（反方向识别和速度差 阈值）和更高级别（方向差阈值和 动态方向相干性和噪声掩蔽的操纵 点图案）能力将被测试。 另外一组 将进行研究，以比较 MT和MST病变具有永久性影响。

There is now substantial evidence of two anatomically and physiologically distinct pathways through primate striate and extra-striate visual cortex. These pathways have been labelled the "motion" and "color and form" pathways, suggesting a detailed knowledge of their individual functions and interactions. However, to date, there is little direct evidence either of the role these pathways play in visual perception, or of their strict independence. The studies proposed here are designed to determine the functional role of these separate pathways in primates by measuring visual loss resulting from damage to one or the other of them. The "motion" pathway will be damaged in one study by lesions of cortical area V2, which will interrupt one of the major projections to area MT, and in a later study by inactivation of MT and/or MST. The :color and form" pathway will be damaged at an early stage in its cortical path by lesions of area V2, and in a separate experiment, by lesions of area V4 itself. Lesions will be produced by localized injections of ibotenic acid into visual field specific regions determined by physiological mapping. Visual thresholds will then be tested during controlled fixation in the visual field locations that correspond to these injections. 1. The first group of studies will assess the effects of V2 lesions on visual capacities basic to both color and motion perception. Visual acuity, luminance and chromatic contrast sensitivity, color matching, and speed and direction difference thresholds will be measured. 2. A second group of studies will examine the role of visual area V4 in the processing of color information. It is expected that removal of this area should disrupt higher level but not simpler aspects of color perception. This hypothesis will be evaluated by testing both basic capacities (luminance and chromatic contrast sensitivity) and more complex abilities (color matching) within the visual field locus corresponding to the lesion. 3. A third set of studies will examine the effect of lesions of visual areas MT and MST on the perception of visual motion. Again both basic (opposite direction discrimination and velocity difference thresholds) and higher level (direction difference thresholds and manipulations of direction coherence and noise masking in dynamic dot patterns) capabilities will be tested. An additional group of studies will be conducted to compare transitory visual effects of MT and MST lesions with permanent effects.