Neural Mechanisms of Visual Discrimination

当物体出现在视野中时，动物会对它们进行定位、辨别，并将头重新定向到最感兴趣的物体。通过分析训练猫不同皮质区损伤后的缺陷来研究参与视觉辨别的皮质通路，以执行后续的视觉辨别任务。猫站着看着前墙的一个水平窗户，透过窗户展示了两个橙色和葡萄的塑料模型，并要求猫头在辨别后将头指向并持续注视正确的物体(橙色)。我们研究了两个视觉系统中的哪一个在视觉辨别中起主要作用，膝状体系统和膝外系统。双侧17-18区消融后，视觉辨别能力几乎没有受到影响。相反，在选择性地一侧消融…上视区之间的外侧视上区(PLL)后，猫不能辨别PLL视野中的物体更多的是受损的半球，但它们通过使用完整大脑的视觉半球来弥补缺陷。我们先前已经证明，上丘(SC)是头部定向的脑干中心。我们研究了头部向SC传递指令的皮层区域。在单侧消融额叶眼野(FEF)后，在投射到SC的皮质区中，对侧定向的潜伏期一过性延长，但其他定向是正常的。然而，猫不能辨别受损大脑视野中的物体，但能够通过使用完好一侧的大脑进行补偿。这表明FEF在辨别后充当皮层输出，并向SC发送命令以执行定向。我们开发了在视觉辨别过程中同时记录多个区域的神经活动的技术。我们现在正在分析与视觉辨别中的各种过程有关的单位活动。较少

When objects appear in the visual field, animals orient to, discriminate between them and redirect the head to the object of most interest. The cortical pathways involving in visual discrimination were studied by analyzing the deficits following lesions of various cortical areas in trained cats to perform the following visual discrimination task. Cats stand watching a horizontal window of the front wall through which two plastic models of orange and grape were presented, and were required to direct the head to and keep fixating the correct object (orange) after discrimination.We studied which of the two visual systems, geniculate and extrageniculate systems, contribute chiefly in this visual discrimination. Following bilateral ablation of areas 17-18, visual discrimination was little affected. In contrast, after selective unilateral ablation of the lateral suprasylvian visual area (PLLS) among suprasylvian visual areas, cats became unable to discriminate objects in the visual field of … More the lesioned hemisphere, but they compensated deficits by using the visual hemifield of the intact brain.We have previously shown that the superior colliculus (SC) is the brain stem center of head orienting. We studied the cortical areas transmitting commands of head orienting to SC. Following unilateral ablation of the frontal eye fields (FEF), among cortical areas projecting to the SC, caused transientincrease in latencies in orienting directing contralateral to the lesion, but otherwise orienting was normal. However, cats could not discriminate objects in the visual field of the lesioned brain, but become able to compensate by using the brain of the intact side. This suggested that FEF acts as the cortical output after discrimination and sends commands to SC for execution of orienting.We developed techniques to record neural activities from multiple areas simultaneously during visual discrimination. We are now analyzing unit activities in relation to various processes in visual discrimination. Less