BINOCULAR VISION AND DEPTH PERCEPTION

这个研究项目的目的是为了理解 灵长类动物大脑皮层立体视觉的机制 深度感知。实验将在警觉的恒河猴身上进行 行为训练，在单身时重复执行一项视觉任务 神经元活动将用一个或多个微电极记录，从 具条纹和具条纹前皮质。刺激将以立体方式呈现 在左眼和右眼分别看到的两个彩色显示器上，以及 使用高速图形系统生成。一个(或两个)的位置 眼睛将被持续监测，以控制猴子的 凝视的方向。其主要目标是获得实验性的 支持或反对差异选择性反应假说的证据 皮质视神经元的数量与立体视觉深度直接相关 感知，并确定不同类型的 立体视觉过程中的神经视差选择性。三行 随后将进行调查：首先，将进行实验以评估 视差选择神经元在视区V1、V2和V3的反应 V3A对立体图形和动态随机网点立体图的不同处理 亮度对比度。观看时立体视觉降低或丢失 等光立体视图样：立体视反应的变化 具有低亮度对比度刺激的猴子的神经元 提示这些神经元在立体视觉中起直接作用。 此外，这些实验的结果将提供关于 哪个解剖-生理视觉子系统(巨细胞或细小细胞) 具有立体属性的神经元是其中的一部分。一系列相关的 实验将被设计来研究潜在的机制 大脑皮层神经元对随机点立体图的反应 为正确匹配提供衬底的机构 两只眼睛中图像的对应元素，这是人类 受试者表现得毫不费力，而且最准确。最后，我会尝试 评估注意力和动机对神经的影响 不同皮质区深度神经元的反应。基本方略 这些实验的其中一个将是训练猴子去注意 刺激，激活正在研究的皮质神经元，并识别 当刺激存在或不存在时神经元反应的差异 与猴子的行为相关。

This program of research aims at an understanding of the operational mechanisms in the cerebral cortex of primates which underlie stereoscopic depth perception. Experiments will be conducted in alert rhesus monkeys behaviorally trained to perform repeatedly a visual task, while single neuron activity will be recorded with one or more microelectrodes from striate and prestriate cortex. Stimuli will be presented stereoscopically on two color displays separately seen by the left and right eyes, and generated with a high-speed graphics system. The position of one (or both) eyes will be monitored continuously in order to control the monkey's direction of gaze. The principal objective is to obtain experimental evidence for or against the hypothesis that disparity-selective responses of cortical visual neurons are directly linked to stereoscopic depth perception, and to ascertain the significance of the different types of the neural disparity selectivity in the stereoscopic process. Three lines of investigation will be followed: First, experiments will be done to assess the responses of disparity selective neurons in visual areas V1, V2 and V3- V3A to solid figure and dynamic random-dot stereograms of different luminance contrast. Stereopsis is degraded or lost when viewing isoluminant stereopatterns: changes in the responses of stereoscopic neurons of monkey with stimuli of low luminance contrast would be a strong indication in favor of a direct role of these neurons in stereopsis. Moreover, the results of these experiments would provide information about which anatomo-physiological visual subsystem (magno- or parvo-cellular) neurons with stero properties are part. An associated series of experiments will be designed to investigate the mechanisms underlying the responses of cortical neurons to random-dot stereograms, that is of the mechanisms providing the substrate for the correct matching of corresponding elements of the images in the two eyes, a task that human subjects perform effortlessly and most accurately. Finally, I will attempt to assess the influences of attention and motivation on the neural responses of depth neurons in different cortical areas. The basic strategy of thee experiments will be to train the monkey to attend to the very stimulus that activates the cortical neuron under study, and to identify differences in the neuron's responses when that stimulus is or is not of behavioral relevance to the monkey.