INFORMATION TRANSFER AND CONTRAST SENSITIVITY IN THE LGN

LGN 中的信息传输和对比度灵敏度

• 批准号: 3259478
• 负责人: EHUD KAPLAN
• 金额: $ 21.24万
• 依托单位: ROCKEFELLER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-09-01 至 1992-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3259478
• 关键词: Macaca; binocular vision; cats; cell type; color visions; corticofugal system; electrophysiology; interneurons; lateral geniculate body; luminescence; neural information processing; neural transmission; psychophysics; retina; retinal ganglion; sequential perception; single cell analysis; stimulus /response; visual feedback; visual perception; visual photosensitivity; visual stimulus

This proposal aims at a better understanding of the functional organization of the central visual pathways of mammals, and attempts to relate visual functions to neuronal populations in the primate. I will focus on two main problems: 1) What are the dynamic properties of the contrast gain control we recently discovered in the Lateral Geniculate Nucleus (LGN)? and 2) What is the neural substrate for the psychophysically determined luminance and color contrast sensitivities? The first question stems from the observations that the LGN is a dynamic filter of the incoming retinal information, and that its filtering (attenuation) of retinal input increases with stimulus contrast. This observation lead to a set of new experiments, in which the contrast of a pattern is modulated in time. I will record in anesthized and paralyzed cats and monkeys the responses of single LGN cells together with their retinal input (recorded as synaptic (S) potentials), and measure the time course with which the LGN adjusts its transmission ratio (LGN response/retinal response) following a step increase in contrast. The importance of temporal and spatial stimulus parameters, as well as that of retinal eccentricity and binocular interactions, will all be explored. The second question is stimulated by the observation that in the monkey LGN the parvocellular neuons (and their drives, the P cells) are much less sensitive to luminance contrast than the magnocellular neurons (or the retinal M cells), and by recent psychophysical work (Mullen, 1985) which compared the contrast sensitivity for color and luminance patterns in humans. I will establish which neuronal population could account for these results by measruing the responses of single P and M cells in the monkey LGN to both luminance and chromatic patterns. I will also measure the sensitivities of the receptor field center and periphery to luminance and color modulations, to uncover the reason for the unbounded increase in response to color stimuli with stimulus size, noted in the P cells, and the source of the difference in contrast gain between M and P cells. The results will shed light on the function of the M cells and P cells in primate vision.

本建议旨在更好地了解 哺乳动物中央视觉通路的组织，以及 试图将视觉功能与大脑中的神经元群体联系起来， 灵长类动物 我将集中讨论两个主要问题：1）什么是 对比度增益控制的动态特性，我们最近 在外侧膝状体核（LGN）中发现的？ （2）什么 是由精神病决定的 亮度和颜色对比敏感度？ 第一个问题源于LGN是一个 输入视网膜信息的动态过滤器， 视网膜输入的过滤（衰减）随着刺激而增加 对比度 这一观察导致了一系列新的实验， 其中图案的对比度在时间上被调制。 我会 在麻醉和瘫痪的猫和猴子中， 单个LGN细胞的反应连同它们的视网膜输入 （记录为突触（S）电位），并测量时间过程 LGN利用该信号调节其传输比（LGN 响应/视网膜响应）。 时间和空间刺激参数的重要性，如 以及视网膜偏心率和双眼相互作用， 都可以探索。 第二个问题是刺激的观察，在 猴LGN小细胞神经元（及其驱动器，P 细胞）对亮度对比度的敏感性比 大细胞神经元（或视网膜M细胞），并通过最近的 心理物理学的工作（马伦，1985年），比较了对比 人类对颜色和亮度模式的敏感度。 我会 确定哪些神经元群体可以解释这些 结果通过测量单个P和M细胞的反应， 猴LGN的亮度和彩色图案。 我会 还测量受体场中心的灵敏度， 外围亮度和颜色调制，以揭示 对颜色刺激的反应无限增加的原因 与刺激大小，注意到在P细胞，和源的 M细胞和P细胞之间的对比度增益差异。 结果 将有助于阐明M细胞和P细胞的功能， 灵长类视觉