PARALLEL PATHWAYS IN PRIMATE VISUAL CORTEX

现在有确凿的证据证明两个解剖学上和 通过灵长类动物纹状体和纹状体的不同生理路径 纹外视皮层。这些小路被贴上了 “运动”和“颜色和形式”的路径，暗示一个详细的 了解它们各自的功能和相互作用。然而， 到目前为止，几乎没有直接证据表明这些人在 路径在视觉感知中发挥作用，或其严格的 独立。 这里提出的研究旨在确定功能 通过测量视觉在灵长类动物中这些独立通路的作用 因损坏其中之一而造成的损失。这个 在一项研究中，“运动”通路将被损伤 大脑皮层V2区，这将中断一个主要的投射 到MT区，并在以后的研究中通过灭活MT和/或MST。 颜色和形式“途径将在早期阶段受损 它的皮质路径由V2区的病变和在一个单独的 实验，通过V4区本身的病变。会产生损伤 通过将鹅掌酸局部注射到特定视野 由生理图谱确定的区域。视觉阈值 然后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 将评估V2损伤对视力的影响 对颜色和运动感知都很基本的能力。视觉 敏锐度、亮度和彩色对比度灵敏度、颜色 匹配，速度和方向差异阈值将是 量过了。2.第二组研究将考察 视觉区域V4在颜色信息处理中的作用。它是 预计这一区域的拆除会扰乱高层建筑，但 而不是颜色感知的更简单的方面。这一假设将是 通过测试基本能力(亮度和色度)进行评估 对比敏感度)和更复杂的能力(配色) 在对应于病变的视野轨迹内。3.A 第三组研究将检查视力损害的影响 MT区和MST区对视觉运动知觉的影响。又一次，两者都是 基本(反向辨别和速度差 阈值)和更高级别(方向差异阈值和 动态中的方向一致性和噪声掩蔽的处理 点模式)功能将进行测试。另一组 将进行研究，以比较短暂的视觉效果 MT和MST损害具有永久性影响。

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.