Development of Visual Function

本研究的目的是建立知觉学习作为弱视治疗策略的价值，并对弱视的神经机制提出新的假设。我们研究了一个非人类灵长类动物的人类视觉系统模型，这样我们就可以在不损害任何儿童视觉福利的情况下研究发育过程和治疗策略，这样我们就可以直接评估发育性视觉障碍的潜在神经相关因素。提出的工作涉及两个一般的调查领域：知觉学习作为弱视的治疗选择的价值，以及弱视是在知觉加工层次的高水平上解码的缺陷。这项工作建立在我们之前的行为和神经生理学研究的基础上，表明弱视视觉系统对视觉信息的编码是相对正常的，不能解释弱视中明显的高阶知觉损失。知觉学习最近被证明对改善成人弱视者的视觉表现是有益的。我们将通过在不同年龄提供具有挑战性的综合感知任务的广泛视觉体验，并评估训练效果转移到其他感知能力的程度以及效果的相对持久性，来确定感知学习是否是一种可行、有效、持久的弱视治疗选择。我们还将研究拥挤的发展，并评估视觉体验对拥挤程度或“临界跨度”的影响。我们的工作假设是，弱视的根本障碍是解码编码的感觉信息之一。我们进一步假设解码缺陷发生在视觉系统的高水平，可能超过MT和V4，并同样影响许多感知过程。我们建议通过测量感知模板，评估感知学习对模板的影响，并记录感知学习对参与感知决策的神经元的影响，来评估弱肢解码异常的本质。提出的工作采用心理物理和生理方法的结合来评估弱视和相关的知觉异常的神经相关性。我们研究正常发育和弱视，以了解成人知觉的重要制约因素。我们的工作将有助于预防儿童弱视的发展，并通过开发儿童友好型培训工具，更有效地治疗这种疾病。

The goals of this work are to establish the value of perceptual learning as a treatment strategy for amblyopia, and to evaluate a new hypothesis for the neural mechanism underlying amblyopia. We study a nonhuman primate model for the human visual system so that we can study developmental processes and treatment strategies without compromising the visual welfare of any child, and so that we can directly assess the underlying neural correlates of developmental visual disability. The proposed work addresses two general areas of investigation: the value of perceptual learning as a treatment option for amblyopia, and the idea that amblyopia is a deficit in decoding at a high level in the perceptual processing hierarchy. This work builds on our prior behavioral and neurophysiological studies showing that the encoding of visual information by the amblyopic visual system is relatively normal and cannot account for the high-order perceptual losses evident in amblyopes. Perceptual learning has recently been demonstrated to be beneficial for improving visual performance in adult amblyopes. We will establish whether or not perceptual learning is a viable, effective, long-lasting treatment option for amblyopia by providing extensive visual experience at different ages with challenging, integrative perceptual tasks, and assessing the degree of transfer of the training effects to other perceptual abilities and the relative permanence of the effects. We will also study the development of crowding and assess the effects of visual experience on the degree or "critical span" of crowding. Our working hypothesis is that the fundamental disorder in amblyopia is one of decoding of the encoded sensory information. We further hypothesize that the decoding deficit occurs at a high level in the visual system, probably beyond MT and V4, and similarly affects many perceptual processes. We propose to evaluate the nature of the decoding abnormality in amblyopes by measuring the perceptual template, evaluating the effects of perceptual learning on the template, and recording the effect of perceptual learning on the neurons that contribute to the perceptual decision. The proposed work employs a combination of psychophysical and physiological methods to evaluate the neural correlates of amblyopia and associated perceptual abnormalities. We study normal development as well as amblyopia to learn about the important constraints on adult perception. Our work will inform efforts to prevent amblyopia development in children and, through the development of child-friendly training tools, more effectively treat the disorder.