STRUCTURE-FUNCTION RELATIONSHIPS IN VISUAL CORTEX

视觉皮层的结构与功能关系

• 批准号: 2160241
• 负责人: ALLEN L HUMPHREY
• 金额: $ 14.61万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-09-01 至 1998-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2160241
• 关键词: brain mapping; cats; electrophysiology; histology; lateral geniculate body; neural conduction; neural information processing; neuronal transport; sequential perception; visual cortex; visual fields; visual pathways; visual perception; visual stimulus

The long range goal of this research program is to understand the structure/function relationships that underlie information processing in the lateral geniculate nucleus (LGN) and visual cortex. Emphasis is on the role of the LGN in temporally transforming afferent signals derived from the retina, and on the contribution these modified signals make to the generation of receptive field structure and visual response properties of neurons in cortical areas 17 and 18. The impetus for the experiments is the finding that the A-laminae of the LGN contain two groups of relay neurons, termed lagged and nonlagged cells, which differ markedly in the timing of their responses to visual stimuli. We have evidence that these timing differences are used in visual cortex to set up the spatiotemporal structure of receptive fields and to create neurons that are sensitive to the direction of stimulus movement. The experiments proposed will reveal the timing properties of neurons in other divisions of the geniculate complex and their potential contribution to the response properties of cortical cells, and determine whether response timing in the LGN and cortex can be modified by abnormal visual stimulation during development. Specific aims are as follows: (1) To characterize the response timing of relay neurons in the geniculate C-laminae and the medial interlaminar nucleus (MIN) in order to complete our ongoing description of geniculate inputs to cortical areas 17 and 18. (2) To examine relationships between the morphological and physiological properties of cells examined in Aim 1, as a basis for elucidating structural mechanisms underlying information processing in the LGN. (3) To reveal the termination zones in cortex of different geniculate cell types, and to search for a sublaminar distribution of afferent types and/or response timing as a basis for interpreting the origin of laminar differences in response timing among cortical cells. (4) To characterize the spatiotemporal structure and direction selectivity of simple cell receptive fields in area 18 and to compare their response timing with that of the geniculate afferents. (5) To investigate the impact of raising animals in a stroboscopically illuminated environment on the response timing of cells in the LGN and (6 and 7) on the spatiotemporal structure of receptive fields in areas 17 and 18. Strobe rearing selectively abolishes direction selectivity in cortex. Parallel changes in response timing between LGN and cortex in these animals will provide further evidence for the role of the LGN in contributing to direction selectivity in cortex. These studies will also provide the first detailed evidence on mechanisms underlying the loss of direction selectivity in strobe-reared animals, and hence contribute to our overall understanding of the substrates for direction selectivity.

该研究计划的长期目标是了解 构成信息处理基础的结构/功能关系 外侧膝状核（LGN）和视觉皮层。 重点是 LGN 在时间变换传入信号中的作用 来自视网膜，以及这些修改后的信号对 感受野结构和视觉反应的生成 皮质区 17 和 18 神经元的特性。 实验发现 LGN 的 A 层包含两个 中继神经元组，称为滞后细胞和非滞后细胞，其不同 明显地表现在他们对视觉刺激的反应时间上。 我们有 有证据表明这些时间差异被视觉皮层用来设置 建立感受野的时空结构并创建神经元 对刺激运动的方向敏感。 这 提出的实验将揭示神经元的计时特性 膝状体复合体的其他部分及其潜力 对皮质细胞反应特性的贡献，并确定 LGN 和皮层的反应时间是否会因异常而改变 发育过程中的视觉刺激。 具体目标如下： (1) 表征响应时序 膝状 C 层和内侧层间的中继神经元 核（MIN）以完成我们正在进行的膝状体描述 输入到皮质区域 17 和 18。 (2) 检查之间的关系 Aim 中检查的细胞的形态和生理特性 1、作为阐明底层结构机制的基础 LGN 中的信息处理。 (3) 揭示终止区 在不同膝状细胞类型的皮层中，并寻找 传入类型和/或响应时间的层下分布 解释响应层状差异起源的基础 皮层细胞之间的时间安排。 (4) 时空特征 简单细胞感受野的结构和方向选择性 区域 18 并将其反应时间与膝状体的反应时间进行比较 传入。 (5) 调查饲养动物的影响 频闪照明环境对细胞响应时间的影响 在 LGN 和（6 和 7）中感受性的时空结构 17 区和 18 区的田地。频闪饲养选择性废除 皮层的方向选择性。 响应时间的并行变化 这些动物的 LGN 和皮质之间的关系将为 LGN 在皮质方向选择性方面的作用。 这些研究还将提供有关机制的第一个详细证据 闪光灯饲养的动物失去方向选择性的潜在原因， 从而有助于我们对底物的整体理解 方向选择性。