VISUAL CHANNELS IN CEREBRAL CORTEX

大脑皮层的视觉通道

• 批准号: 2159650
• 负责人: John H.R. Maunsell
• 金额: $ 24.6万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-09-01 至 1998-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2159650
• 关键词: Macaca; electrophysiology; experimental brain lesion; histology; lateral geniculate body; neural conduction; neural information processing; neuroanatomy; neurons; visual cortex; visual feedback; visual pathways

The idea that the primate visual system contains parallel streams of processing that arise in the retina remain relatively independent throughout visual cortex has recently commanded considerable attention, and has led to far-reaching speculation about its functional consequences, Parallel organization is obvious at all levels of the geniculocortical system, including the sub-cortical pathway leading to cortex, the early stages of cortex, and the highest levels of cortical processing. However, the mapping of parallel components in one level onto those at the next has not been established conclusively. It is not known whether components in each stage map directly onto those at the next level, creating truly parallel pathways, or if instead a gradual intermixing eliminates any exclusive relationship between components in the different stages. While many lines of evidence suggest that the geniculocortical system in fact does contains largely independent pathways. there is also clear evidence of intermixing. The proposed experiments will continue on-going work that is aimed at evaluating the degree of parallel organization in monkey visual cortex. Conclusive answers cannot be provided either by anatomical studies or by those that examine similarities in response properties at different levels. Instead, the proposed experiments will record from cortical cells while reversibly inactivating individual magnocellular or parvocellular layers in the lateral geniculate nucleus (LGN). This is a method that the investigators have applied successfully to demonstrate that neurons in the middle temporal visual area (MT) depend primarily on the magnocellular layers on the LGN for their excitatory drive. The proposed experiments will address several specific questions about segregation of magnocellular (M channel) and parvocellular (P channel) contributions to visual cortex. 1) Does the degree of P and M channel segregation seen at the level of MT persist throughout visual cortex, or does it gradually erode in later stages? 2) Given that the P and M channels have been shown to mix to some extent, what are the special properties conferred by mixing? 3) How are the (two) P and M channels distributed across the three pathways that have been identified in the early stages of visual cortex using cytochrome oxidase stain?

灵长类动物视觉系统包含平行流的想法 在视网膜中出现的处理仍然相对独立 整个Visual Cortex最近都引起了广泛关注， 并导致了有关其功能的深远猜测 后果，平行组织在各个层面上都是显而易见的 基因皮层系统，包括导致 皮质，皮质的早期阶段和最高水平的皮质 加工。但是，在一个级别上平行组件的映射到 下一个的人尚未确定。这是不知道的 每个阶段中的组件是否直接映射到下一个组件 级别，创建真正的并行途径，或者如果逐渐 混合消除了组件之间的任何独家关系 不同的阶段。虽然许多证据表明 实际上，基因皮层系统确实包含很大程度上独立的 途径。也有明确的混合证据。 拟议的实验将继续进行，以 评估猴子视觉皮层中平行组织的程度。 结论性答案不能由解剖学研究或 那些在不同的响应属性中检查相似性的人 水平。相反，提出的实验将记录从皮质细胞记录 虽然可逆地灭活个体的大细胞或副细胞 横向基因核（LGN）中的层。这是一种方法 调查人员已成功申请了该神经元中的神经元 中间时间视觉区域（MT）主要取决于 LGN上的巨细胞层以进行兴奋性驱动。 拟议的实验将解决有关的几个特定问题 巨细胞（M通道）和副细胞（P通道）的分离 对视觉皮层的贡献。 1）p和m通道的程度 在整个视觉皮层中，MT持续存在的隔离，或 它会逐渐在以后的阶段侵蚀吗？ 2）鉴于P和M 频道已被证明在某种程度上混合了什么特殊 混合赋予的属性？ 3）（两个）P和M通道如何 分布在已经确定的三个途径上 使用细胞色素氧化酶染色的视觉皮层的早期阶段？