Visual Crowding

视觉拥挤

• 批准号: 9637390
• 负责人: ADAM KOHN
• 金额: $ 20.6万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 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 2023-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9637390
• 关键词: Visual; Crowding

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.

摘要 拥挤是一种感知现象，在这种现象中，清晰可辨的刺激变得无法辨认 因为附近的‘分心物’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力中更强，它强烈地影响 中心视力丧失(如黄斑变性)，对其质量有实质性影响的个人 生活的一部分。拥挤在人类心理物理研究中得到了广泛的探索。功能成像和 人类的电生理学研究已经提供了一些早期和中期拥挤的神经关联 视觉皮质，但拥挤的神经基础在很大程度上仍未被探索和了解。这 该项目将确定拥挤的展示如何影响神经元对感觉信息的呈现 低层和中层皮层的人群(编码)，拥挤如何影响这种感觉的方式 信息被用来做出感知判断(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。在特定的目标1中，我们将记录来自 猕猴的初级视觉皮质(V1和V4)。我们将检验这一假设，即拥挤会导致腐败 这些区域的感觉表征。我们将确定拥挤的展示如何影响神经元的反应性， 调谐、可变性和神经元间噪声相关性。利用认识上的最新进展 群体编码，我们将评估这些反应特征的概率如何组合在一起影响视觉编码 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位辨别 任务，对于孤立呈现和有干扰的目标刺激。我们将使用一种刺激模式，允许 美国将计算“心理物理核心”--一种评估感知策略的方法，不同的 视觉显示的元素被组合在一起以做出决定。我们将把这些行为指标与 记录V1和V4中的神经元数量，以推断动物用于联系的读出策略 对知觉决定的感官反应。这些实验将检验这样一种假设，即拥挤在 部分来自对感官信息的次优读出。在具体目标3中，我们将测试短暂的 视觉适应可以缓解拥挤。我们假设适应可以用来改善显著程度。 对于新的刺激，具有更高的突出性，从而改善了知觉表现。我们将测试我们的 假设通过测量单独或有干扰的目标刺激的总体信息，在 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出 动物在我们的方位辨别任务中使用的策略。这些实验将揭示哪些方面的 拥挤大多是塑料的，并测试了一种新的感官适应功能好处。我们的目标将共同努力 对拥挤的神经基础进行全面调查，提供发展所需的知识 治疗和行为策略，以缓解拥挤引起的生活质量问题。