Visual Crowding

视觉拥挤

• 批准号: 9704285
• 负责人: ADAM KOHN
• 金额: $ 4.83万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE, INC
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-02-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9704285
• 关键词: Affect; Amblyopia; Animals; Area; Behavioral; Blindness; Books; Code; Complex; Crowding; Decision Making; Discrimination; Dyslexia; Electrophysiology (science); Elements; Functional Imaging; Human; Individual; Injury; Interneurons; Investigation; Judgment; Knowledge; Macaca; Macular degeneration; Measures; Methods; Monkeys; Neurons; Noise; Ocular Prosthesis; Perception; Performance; Population; Psychophysics; Quality of life; Reading; Recovery; Sensory; Stimulus; Stroke; System; Testing; Therapeutic; Training; Vision; Vision Disorders; Visual; Visual Cortex; Visual Pathways; area V4; area striata; behavior measurement; experience; experimental study; improved; neural correlate; neuromechanism; novel; patient population; relating to nervous system; response; sample fixation; spatial vision; therapy development; visual adaptation; visual information; visual performance; visual processing

Summary Crowding is a perceptual phenomenon in which a clearly discernible stimulus becomes unrecognizable because of nearby `distractor' stimuli. Crowding affects core aspects of visual processing, including feature integration, scene perception and reading. Because crowding is stronger in non-foveal vision, it strongly affects individuals with central vision loss (e.g. macular degeneration), with substantial consequences for their quality of life. Crowding has been explored extensively in human psychophysical studies. Functional imaging and electrophysiological studies in humans have provided some neural correlates of crowding in early and midlevel visual cortex, but the neural underpinnings of crowding remain largely unexplored and poorly understood. This project will determine how crowded displays affect the representation of sensory information by neuronal populations in low and midlevel cortex (encoding), how crowding affects the manner in which this sensory information is used to make perceptual judgments (decoding), and whether the effects of crowding can be mitigated by brief periods of sensory experience. In Specific Aim 1, we will record from neuronal populations in primary visual cortex (V1) and V4 of macaque monkeys. We will test the hypothesis that crowding corrupts sensory representations in these areas. We will determine how crowded displays affect neuronal responsivity, tuning, and variability, and interneuronal noise correlations. Making use of recent advances in understanding population codes, we will assess how chances in these response features combine to affect encoding of visual information with crowding. In Specific Aim 2, we will train animals to perform a fine orientation discrimination task, for target stimuli presented in isolation and with distractors. We will use a stimulus paradigm that allows us to compute “psychophysical kernels”—a method for assessing perceptual strategy by which different elements of a visual display are combined to make decisions. We will pair these behavioral measures with recordings of neuronal population in V1 and V4, to infer the read-out strategy used by the animal to relate sensory responses to perceptual decisions. These experiments will test the hypothesis that crowding arises in part from suboptimal read out of sensory information. In Specific Aim 3, we will test whether brief periods of visual adaptation can mitigate crowding. We hypothesize that adaptation can be used to improve the salience of novel stimuli, with heightened salience resulting in improved perceptual performance. We will test our hypothesis by measuring the population information for target stimuli in isolation or with distractors, under control conditions and different adaptation states. We will also test whether adaptation alters the read-out strategy used by animals in our orientation discrimination task. These experiments will reveal which aspects of crowding are most plastic, and test for a novel functional benefit of sensory adaptation. Together our aims will provide a comprehensive investigation of the neural basis of crowding, providing knowledge needed to develop therapeutic and behavioral strategies to alleviate the quality of life issues caused by crowding.

总结 拥挤是一种感知现象，在这种现象中，一个清晰可辨的刺激变得无法识别 因为附近的“干扰物”刺激。拥挤影响视觉处理的核心方面，包括特征 整合、情景感知和阅读。因为拥挤在非中心凹视觉中更强，它强烈影响 患有中心视力丧失（例如黄斑变性）的个体，对他们的质量有重大影响 生命拥挤在人类心理物理学研究中得到了广泛的研究。功能成像和 对人类的电生理学研究提供了一些早期和中期拥挤的神经相关性， 视觉皮层，但拥挤的神经基础仍然在很大程度上未被探索和了解甚少。这 一个项目将确定拥挤的显示器如何影响神经元对感官信息的表达。 人群在低和中级皮层（编码），拥挤如何影响这种感觉的方式， 信息被用来进行感知判断（解码），以及拥挤的影响是否可以 通过短暂的感官体验来缓解。在具体目标1中，我们将记录来自神经元群体的 猕猴的初级视皮层（V1）和V4。我们将检验拥挤会导致腐败的假设 这些区域的感官表征。我们将确定拥挤的显示如何影响神经元的反应， 调谐、变异性和神经元间噪声相关性。利用最新进展， 人口代码，我们将评估如何在这些反应功能的机会联合收割机结合，以影响编码的视觉 信息与拥挤在具体目标2中，我们将训练动物进行精细的方向辨别 任务，为目标刺激孤立和干扰。我们将使用一种刺激模式， 我们计算“心理物理内核”-一种评估感知策略的方法， 视觉显示的元素被组合以做出决定。我们将把这些行为指标与 记录V1和V4中的神经元群体，以推断动物使用的读出策略， 感知决定的感官反应。这些实验将检验拥挤产生于 部分从次优读出感官信息。在具体目标3中，我们将测试短期内 视觉适应可以缓解拥挤。我们假设，适应可以用来提高显着性 新的刺激，提高了显着性，从而提高了感知性能。我们将测试 假设通过测量人口信息的目标刺激孤立或干扰，根据 控制条件和不同的适应状态。我们还将测试适应是否会改变读数 在我们的方向辨别任务中动物使用的策略。这些实验将揭示 拥挤是最具可塑性的，并且测试了感觉适应的新功能益处。我们的目标将 提供拥挤的神经基础的全面调查，提供发展所需的知识， 治疗和行为策略，以减轻拥挤造成的生活质量问题。