Central Scotomas in AMD and Cortical Remapping

AMD 和皮质重映射中的中心盲点

• 批准号: 6858538
• 负责人: JANET S SUNNESS
• 金额: $ 12.21万
• 依托单位: GREATER BALTIMORE MEDICAL CENTER, INC.
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6858538
• 关键词: aging; behavioral /social science research tag; binocular vision; brain mapping; clinical research; eye fundus photography; eye movements; eye regeneration; functional magnetic resonance imaging; human subject; macular degeneration; neural plasticity; neuroanatomy; ophthalmoscopy; retinal adaptation; scotoma; vision tests; visual cortex; visual fields; visual fixation; visual perception; visual stimulus

DESCRIPTION (provided by applicant): Age-related macular degeneration (AMD) is the leading cause of severe vision loss in the population over the age of 60. Patients with the advanced forms of AMD have central scotomas (blind spots) in their field of vision. One of the challenges of low vision intervention is to help these patients use eccentric retina when their central retina is blind. One factor in using eccentric retina effectively may be remapping of the visual cortex. Until the early 1990s, it was widely believed that the anatomical structure of cortical tissue did not change once it was established following early development. However, evidence has now accumulated showing rapid and dramatic cortical plasticity in adulthood following the loss of sensory input due to peripheral lesions. For example, amputation of a limb first causes the cortex previously receiving input from that limb to be silent, but shortly thereafter, this region begins to respond to stimulation of adjacent regions of the skin. It is believed that changes in the efficacy of lateral connections within cortex are responsible for this phenomenon. In the visual system, there is some evidence from cellular recordings in animals with scotomas caused by laser treatment to the retina, and from filling-in phenomena in humans, that such remapping does occur, but its relationship to visual function has not been characterized. In the proposed project, we will investigate changes in the cortical mapping of retinal input using functional magnetic resonance imaging (fMRI) in humans with retinal lesions caused by geographic atrophy, the advanced atrophic form of age-related macular degeneration (AMD) and a model system for studying central scotomas in general. The specific aims of this proposal are (1) to determine the nature and extent of cortical remapping in patients with central scotomas from AMD using fMRI, following a detailed assessment of retinal function with a scanning laser ophthalmoscope, and (2) to determine whether and how cortical remapping contributes to the development of a stable eccentric preferred retinal locus in these patients.

描述（由申请人提供）：与年龄相关的黄斑变性（AMD）是60岁以上人口严重视力丧失的主要原因。AMD高级形式的患者在视力领域中具有中央的Scotomas（盲点）。低视力干预的挑战之一是帮助这些患者在中央视网膜盲目时使用偏心的视网膜。有效使用偏心视网膜的一个因素可能是对视觉皮层进行重新映射。 直到1990年代初，人们普遍认为，一旦早期发育建立了皮质组织的解剖结构。 然而，现在已经积累了证据，表明由于周围病变导致的感觉输入丧失后，成年后的迅速和戏剧性的皮质可塑性。例如，肢体的截肢首先导致先前接收到该肢体输入的皮质保持沉默，但此后不久，该区域开始对皮肤相邻区域的刺激做出反应。人们认为，皮质内侧连接功效的变化是该现象的原因。 在视觉系统中，有一些证据来自由激光治疗视网膜引起的Scotomas动物的细胞记录，以及人类中的填充现象确实发生了这种重新映射，但其与视觉功能的关系尚未表征。 在拟议的项目中，我们将使用功能性磁共振成像（fMRI）研究视网膜输入的皮质图的变化（fMRI），该人具有由地理萎缩引起的视网膜病变的人类，这是年龄相关的黄斑变性（AMD）的高级萎缩形式和用于研究中央scotomas的模型系统。 The specific aims of this proposal are (1) to determine the nature and extent of cortical remapping in patients with central scotomas from AMD using fMRI, following a detailed assessment of retinal function with a scanning laser ophthalmoscope, and (2) to determine whether and how cortical remapping contributes to the development of a stable eccentric preferred retinal locus in these patients.