Plasticity of development of vision and of the mammalian central visual pathways

视觉发育和哺乳动物中央视觉通路的可塑性

• 批准号: 7660-2010
• 负责人: Mitchell, Donald
• 金额: $ 3.64万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2010
• 资助国家: 加拿大
• 起止时间: 2010-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=450140
• 关键词: Plasticity; development; vision; mammalian; central

The major objective of my research program is to understand how the development of the pathways in the brain that process vision, and hence vision itself, are influenced by what an animal sees early in its life. From studies on animal species such as monkeys and kittens that have visual systems organized for accurate binocular depth perception (stereoscopic vision) like that of humans, it is known that there are so called "critical periods" in development during which abnormal or biased visual input can have a permanent effect on the development of the visual pathways which in turn result in visual impairments. The altered development of the visual pathways induced by an episode of abnormal early visual input is now thought to underlie the common (~3% of the population) developmental visual disorder called amblyopia ("lazy eye"), that is defined as poor vision that does not originate in the eye itself. The experiments I conduct explore the origins of this disorder through studies of how certain forms of abnormal input influence the vision of cats including their ability to perceive motion, to follow moving objects with their head and eyes and to strike at them with one of their paws. The majority of the experiments involve evaluations of the vision of the kittens by use of visual displays and tasks similar to those used to test the vision of amblyopic humans. A central theme of the experiments is the idea that not all visual input is treated equally during development; brief periods of normal binocular input where the two eyes see the same thing simultaneously, are weighted preferentially to prevent the development of amblyopia even when most visual input is grossly abnormal. I will examine whether the critical amount of binocular input is determined by the proportion of input that is normal or by an absolute amount of such input. In addition, I will examine whether division of the abnormal input into separate episodes will weaken its effectiveness.

我的研究项目的主要目的是了解大脑中处理视觉的通路的发展，以及视觉本身，是如何受到动物早期所看到的东西的影响的。根据对猴子和小猫等动物物种的研究，这些动物的视觉系统与人类一样具有准确的双目深度感知（立体视觉），我们知道，在发育过程中存在所谓的“关键时期”，在此期间，异常或有偏见的视觉输入可能对视觉通路的发展产生永久性影响，从而导致视觉障碍。由早期视觉输入异常引起的视觉通路发育的改变现在被认为是常见的（约占人口的3%）发育性视觉障碍的基础，称为弱视（“懒眼”），它被定义为不是由眼睛本身引起的视力低下。我进行的实验通过研究某些形式的异常输入如何影响猫的视觉，包括它们感知运动的能力，用头和眼睛跟随移动物体的能力，以及用一只爪子攻击它们的能力，来探索这种疾病的起源。大多数实验都是通过视觉展示和类似于测试弱视人类视力的任务来评估小猫的视力。这些实验的一个中心主题是，并非所有视觉输入在开发过程中都得到平等对待；即使在大多数视觉输入严重不正常的情况下，双眼同时看到同一事物的短暂正常双眼输入被优先加权，以防止弱视的发展。我将研究双眼输入的临界量是由正常输入的比例决定的还是由这种输入的绝对数量决定的。此外，我将检验将异常输入划分为单独的片段是否会削弱其有效性。