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.

概括 拥挤是一种感知现象，在这种现象中，明显可见的刺激变得无法识别 由于附近的“干扰器”刺激会影响视觉处理的核心方面 集成，场景的渗透和阅读，因为拥挤在非视觉中更强烈 具有中心视力丧失的个体（例如Macullar变性），其质量具有很大的奉献 生活中的人群广泛探讨了人类的心理学研究 人类的电生理学研究已经证明了早期和中级拥挤的一些神经相关性 视觉皮层，但拥挤的神经基础在很大程度上尚未探索和了解不足。 通过确定拥挤的显示如何影响神经元的感觉信息的代表 低层和中级皮层（编码）中的爆炸，拥挤如何影响这种感觉的方式 信息用于做出感知判断（解码），以及拥挤的影响是否可以是 通过短暂的感官经验来减轻特定目标。 猕猴的一级视觉皮层（V1）和V4。 在这些领域的感觉代表。 调整，可变性以及神经元间噪声相关性。 人口代码，我们将评估这些响应功能中的机会如何结合起来影响视觉的编码 在特定的目标2中，我们将训练动物进行精细的方向歧视 任务，用于孤立的目标刺激和干扰物。 我们要计算“心理物理核” - 一种评估感知策略的方法 粘贴的要素合并为决定。 V1和V4中神经元种群的记录，以推断动物用于关联的读出策略 对感知决定的感觉反应。 一部分是从特定目标中读取的次优信息。 视觉适应可以减轻拥挤。 新颖的刺激，带有Hightened Saliance导致感知性能的改善。 假设通过孤立或分散者的群体刺激的人口信息，在 控制条件和不同的适应状态。 动物在我们的取向中使用的策略。 人拥挤是最塑料的，并且对我们的目标进行了新的功能益处。 对拥挤的神经基础进行全面调查，提供发展所需的知识 减轻拥挤引起的质量问题的治疗和行为策略。