DYNAMIC PROPERTIES OF ADULT VISUAL CORTEX--ROLE OF NO

成人视觉皮层的动态特性——NO 的作用

• 批准号: 6624953
• 负责人: MICHAEL J FRIEDLANDER
• 金额: $ 28.7万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-07-01 至 2004-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6624953
• 关键词: NMDA receptors; binocular vision; cats; electrophysiology; fluorescent dye /probe; laboratory rat; long term potentiation; mature animal; neural information processing; neural plasticity; neurons; nitric oxide; synapses; tissue /cell culture; visual cortex; visual deprivation; visual stimulus

DESCRIPTION (Adapted from applicant's abstract): The visual areas of the cerebral cortex of humans and other mammals are known to be highly susceptible to environmental factors during critical periods of postnatal development. Thus, various types of peripheral insult such as unequal binocular vision due to ptosis, congenital cataracts, unequal ammetropia or strabismus in addition to traumatic injury or eye infection during postnatal development can lead to permanent deficits in cortical processing of retinal output. The adult visual cortex was thought to be less susceptible to peripheral effects and less able to functionally reorganize in an adaptive way. However, recent evidence suggests that the adult visual cortex is capable of functional reorganization--both transient and permanent. A recently discovered molecule, nitric oxide (NO), that is made by neurons in the adult visual cortex, has been suggested to play a role in modulating the efficiency of chemical synaptic communication. We have previously demonstrated that up-regulation of the brain's endogenous NO-synthesis in the adult feline primary visual cortex amplifies the visual responses and enhances signal detection by individual neurons in response to suprathreshold visual stimuli presented monocularly. However, the effects of NO on binocular integration and threshold sensitivity are not known. Moreover, nothing is known regarding the potential capacity for NO to modulate response in monocularly visually derived animals (a model for amblyopia in human). Thus, we plan to investigate in quantitative fashion, the effects of endogenously synthesized NO on monocular contrast response functions, contrast threshold, response reliability, and binocular integration by individual neurons in the normal adult and amblyoptic monocularly deprived cat. To accomplish this, we will drifting randomly, interleaved sine-wave grating stimuli in conjunction with multi-barrel iontophoresis of endogenous NO up-and/or down-regulating compounds and extracellular single-unit recording to locally modify the NO environment in cortex while evaluating cells' visual responses. We will also utilize a new family of fluorescent dyes that detect NO production from neurons in vitro to characterize their functional properties and anatomical relationship to ocular dominance column (in normal adult cats and rats and monocularly visually deprived cats), in vitro.

描述（改编自申请人的摘要）：视觉区域 已知人类和其他哺乳动物的大脑皮层高度敏感 产后发育关键时期的环境因素。 因此，各种类型的外周损伤，例如由于双眼视力不均等 另外还有上睑下垂、先天性白内障、不等屈光不正或斜视 出生后发育期间的外伤或眼部感染可能导致 视网膜输出的皮质处理永久性缺陷。成人视觉 人们认为皮质不太容易受到周围效应的影响，并且能力较差 以适应性方式进行功能重组。然而，最近的证据 表明成人视觉皮层能够发挥功能 重组——暂时的和永久的。最近发现的一种分子， 一氧化氮 (NO) 是由成人视觉皮层神经元产生的 建议在调节化学突触效率中发挥作用 沟通。我们之前已经证明，上调 成年猫初级视觉皮层大脑内源性 NO 合成 放大视觉反应并增强个体的信号检测 神经元对单眼呈现的阈上视觉刺激做出反应。 然而，NO 对双眼整合和阈值敏感性的影响 不知道。此外，对于潜在的能力一无所知。 NO 调节单眼视觉衍生动物的反应（一个模型） 人类弱视）。因此，我们计划以定量的方式研究 内源合成NO对单眼对比反应的影响 功能、对比度阈值、响应可靠性和双眼积分 由正常成人和弱视单眼剥夺的个体神经元 猫。为了实现这一点，我们将随机漂移、交错的正弦波 光栅刺激与内源性 NO 的多管离子电渗疗法相结合 上调和/或下调化合物和细胞外单单位记录 在评估细胞视觉的同时局部修改皮质中的 NO 环境 回应。我们还将利用一系列新的荧光染料来检测 NO 体外神经元的产生以表征其功能特性 以及与眼优势柱的解剖关系（在正常成年猫中 以及大鼠和单眼视力丧失的猫），体外。