Reorganization of Visual Cortex in Macular Disease

黄斑疾病中视觉皮层的重组

• 批准号: 7487319
• 负责人: NANCY KANWISHER
• 金额: $ 36.52万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-02 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7487319
• 关键词: Accommodation phosphene; Accounting; Adult; Affect; Age; Age of Onset; American; Behavior; Behavioral; Bilateral; Blindness; Characteristics; Clinical; Condition; Contrast Sensitivity; Data; Detection; Development; Disease; Employee Strikes; Face; Functional Magnetic Resonance Imaging; Individual; Learning; Location; Macular degeneration; Maps; Methods; Neurosciences; Performance; Peripheral; Play; Process; Psychophysiology; Reading; Rehabilitation therapy; Research; Residual state; Retina; Retinal; Retinitis Pigmentosa; Role; Running; Scanning; Scotoma; Severities; Signal Transduction; Stimulus; Testing; Thalamic structure; Time; Transcranial magnetic stimulation; Vision; Visual; Visual Cortex; Visual Fields; Visual impairment; coping; disorder of macula of retina; fovea centralis; gaze; macula; monocular; neuromechanism; rehabilitation strategy; remediation; research study; retinal damage; retinotopic; visual information; visual performance; visual stimulus

DESCRIPTION (provided by applicant): Macular degeneration (MD)-the loss of central vision due to retinal damage-is the leading cause of visual impairment in the developed world, affecting more than 1.6 million Americans over the age of 50. Individuals with loss of central vision must learn to cope with peripheral vision only, which has low acuity and contrast sensitivity. In normal subjects, a large region of visual cortex is allocated to processing visual information at the center of gaze, and an understanding of what happens to this cortical region when its input is cut off by MD will be critical in any effort to develop better methods of vision rehabilitation. Pilot fMRI data from our lab shows a striking and previously undescribed phenomenon in which the region of visual cortex that responds to the fovea in normal subjects is strongly activated by peripheral stimuli in MD subjects, indicating functional reorganization of retinotopic cortex (FRRC) in MD. The research outlined in this proposal will use fMRI scanning of MD subjects as well normal control subjects while they view visual stimuli, in order to test the following hypotheses about MD: i) that FRRC occurs rapidly after the onset of MD and strengthens over time, such that we will find FRRC in every binocular MD subject who has central field loss, including those who have developed the disease very recently, ii) that FRRC occurs even in monocular MD, although more slowly than in binocular MD, iii) that formerly foveal cortex will respond primarily or only to stimuli presented in the "preferred retinal locus" (i.e. that part of the surviving retina that MD subjects use preferentially for tasks such as reading and face recognition), iv) that FRRC will be found only when the scotomas cover the fovea, not when the fovea is spared and the peripheral visual field is compromised, and v) that formerly foveal cortex contributes to visual performance in MD subjects, but does so for peripheral (rather than central) visual space. This research is important for three reasons: 1) It will inform research into the basic neuroscience of cortical plasticity and its relationship to behavior; 2), It will answer fundamental questions about the neural mechanisms by which MD subjects cope with loss of central vision; 3) It will help guide the search for better rehabilitation strategies for people with MD.

描述（由申请人提供）：黄斑变性（MD）——由于视网膜损伤而导致中央视力丧失——是发达国家视力障碍的主要原因，影响着超过 160 万 50 岁以上的美国人。中央视力丧失的个人必须学会仅应对周边视力，而周边视力的敏锐度和对比敏感度较低。在正常受试者中，视觉皮层的一大片区域被分配来处理注视中心的视觉信息，了解当该皮层区域的输入被 MD 切断时会发生什么，对于开发更好的视力康复方法至关重要。我们实验室的初步功能磁共振成像数据显示了一个引人注目的、以前未被描述的现象，即正常受试者中对中央凹做出反应的视觉皮层区域被MD受试者的周围刺激强烈激活，这表明MD受试者中视网膜专题皮层（FRRC）的功能重组。本提案中概述的研究将在 MD 受试者以及正常对照受试者观看视觉刺激时使用 fMRI 扫描，以测试有关 MD 的以下假设：i) FRRC 在 MD 发病后迅速发生，并随着时间的推移而加强，这样我们将在每个患有中心视野丧失的双眼 MD 受试者中发现 FRRC，包括最近患上该疾病的受试者，ii) FRRC 即使在 单眼 MD，尽管比双眼 MD 慢，iii) 以前的中心凹皮层将主要或仅对“首选视网膜位点”（即 MD 受试者优先使用的幸存视网膜部分用于阅读和面部识别等任务）中出现的刺激做出反应，iv) 仅当暗点覆盖中央凹时才会发现 FRRC，而不是当中央凹不受干扰时才会发现 FRRC 周边视野受到损害，v) 以前的中央凹皮层有助于 MD 受试者的视觉表现，但对周边（而不是中央）视觉空间起作用。这项研究之所以重要，有以下三个原因：1）它将为皮质可塑性及其与行为关系的基础神经科学研究提供信息； 2)、它将回答MD受试者应对中心视力丧失的神经机制的基本问题； 3) 它将有助于指导MD患者寻找更好的康复策略。