Function of Fixational Instability During Natural Viewing

自然观看过程中注视不稳定性的作用

• 批准号: 10176500
• 负责人: MICHELE RUCCI
• 金额: $ 44.2万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-30 至 2022-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10176500
• 关键词: Address; Advocate; Affect; Automobile Driving; Characteristics; Code; Data; Detection; Development; Discrimination; Disease; Elements; Eye; Eye Abnormalities; Eye Movements; Form Perception; Frequencies; Funding; Goals; Human; Image; Image Enhancement; Individual; Joints; Light; Link; Location; Mainstreaming; Maps; Measurement; Measures; Modeling; Movement; Neurons; Ophthalmology; Optics; Outcome; Pathway interactions; Pattern; Perception; Periodicity; Physiological; Play; Process; Property; Prosthesis; Research; Resolution; Rest; Retina; Role; Saccades; Scheme; Signal Transduction; Smooth Pursuit; Statistical Data Interpretation; Stereotyping; Stimulus; System; Testing; Theoretical Studies; Time; United States National Institutes of Health; Vision; Visual; Visual Psychophysics; Visual impairment; Visual system structure; Work; base; data modeling; density; design; experimental study; flexibility; fovea centralis; gaze; information processing; interest; luminance; mathematical model; motor control; neural model; neuromechanism; novel; oculomotor; outcome prediction; rehabilitation strategy; relating to nervous system; retinal imaging; retinal neuron; retinal stimulation; sample fixation; spatiotemporal; theories; transmission process; visual coding; visual information; visual neuroscience; visual processing; visual tracking

PROJECT SUMMARY Human eyes are never at rest. Gaze redirections normally occur 2-3 times/second, separating periods of small, incessant eye movements. At first glance, the function of eye movements seems obvious: they are necessary to bring and maintain the object of interest within the foveola, the highest acuity region of the retina. However, an overwhelming body of evidence, in part coming from our NIH-funded research, indicates that this view is simplistic and that, by reformatting a spatial scene into a spatiotemporal stimulus on the retina, eye movements serve fundamental visual functions beyond just orienting the foveola. Here we test several new hypotheses concerning less-obvious but equally critical roles for three main kinds of eye movements: saccades, pursuit, and fixational drift (the eye jitter that continually occurs during fixation). The research strategy consists of evaluating the effect of eye movements on the retinal input and the resulting consequences for neural coding, perception, and control. The experiments rely on state-of-the-art high-resolution measurements of human eye movements and gaze-contingent control of retinal stimulation. All experiments are supported by mathematical modeling of visual input signals and neural modeling of their encoding consequences. Aim 1 focuses on the physiological alternation between saccades and fixational drift. Stereotyped, saccade-induced transients are followed by stereotyped, but distinct, periods of Brownian-like jitter of the retinal image. Our preliminary analyses show that this alternation repackages the energy of natural scenes into different spatiotemporal formats, cyclically varying amplification and spectral distribution within the temporal sensitivity bandwidth of retinal neurons. The predicted outcomes are oculomotor-driven dynamics of visual sensitivity, discrimination, and form perception during natural post- saccadic fixation, which we will quantify and test. Aim 2 focuses on the saccades themselves. We predict that, as a consequence of a saccade, the spectral density of the visual input effective in driving retinal neurons at fixation onset is equalized up to a cut-off spatial frequency that depends on the saccade amplitude. This effect further constrains visual dynamics and implies that visual coding during early fixation depends on the amplitude of the preceding saccade. It also suggests that the visual system can exploit this tuning according to the task. We will test these predictions by isolating the contributions of saccade transients in a variety of low- and high-level visual tasks. Aim 3 further generalizes these ideas. Building on our modeling work, it examines whether fixational drift can also be adjusted to tune visual sensitivity to the task demands, and whether the alternation between pursuit movements and “catch-up” saccades during visual tracking plays a role similar to that of saccade/drift cycle for static targets. All our hypotheses are supported by preliminary data. They are, to our knowledge, entirely novel, and confirmation of any of them will have broad implications for understanding the design principles of the visual system, possible oculomotor contributions to neuro-ophthalmologic disorders, and the development of rehabilitative strategies and prostheses.

项目总结 人类的眼睛永远不会休息。凝视重定向通常发生2-3次/秒，分隔小的、 眼睛不停地运动。乍一看，眼球运动的功能似乎是显而易见的：它们是必要的 将感兴趣的物体带到并保持在中心凹内，这是视网膜的最高敏锐度区域。然而， 来自美国国立卫生研究院资助的研究的大量证据表明，这种观点 简单化，通过将空间场景重新格式化为视网膜上的时空刺激，眼睛运动 提供基本的视觉功能，而不仅仅是定位中心凹。在这里，我们测试几个新的假设 关于三种主要眼动的不太明显但同样关键的角色：扫视、追逐和 fix轴漂移(fix轴运动期间持续出现的眼睛抖动)。研究策略包括评估 眼球运动对视网膜输入的影响以及由此导致的神经编码、感知和 控制力。这些实验依赖于最先进的高分辨率测量人类眼球运动和 视觉性视网膜刺激控制。所有的实验都由可视化的数学模型支持 输入信号及其编码结果的神经建模。目标1侧重于生理变化 在眼跳和fi运动漂移之间。千篇一律的、由眼跳引起的瞬变之后是千篇一律的，但 视网膜图像有明显的布朗样抖动周期。我们的初步分析表明，这一变化 将自然场景的能量重新打包成不同的时空格式，循环变化的fi放大 以及视网膜神经元时间敏感性带宽内的频谱分布。预测的结果 是由动眼运动驱动的视觉敏感度、辨别力和形状知觉的动态变化 跳动的fi，我们将对其进行量化和测试。目标2关注的是扫视本身。我们预测，由于 眼跳的结果，视觉输入的光谱密度在fixation时有效地驱动视网膜神经元 起跳被均衡到取决于扫视幅度的截止空间频率。这一效果进一步 约束视觉动态，并暗示早期fiXation期间的视觉编码取决于 之前的扫视。它还表明，视觉系统可以根据任务来利用这种调整。我们会 通过在各种低水平和高水平视觉中分离眼跳瞬变的贡献来测试这些预测 任务。目标3进一步概括了这些想法。在我们的建模工作的基础上，它检查了fi的xational漂移 还可以调整视觉敏感度，以适应任务的需求，以及是否在追逐之间交替 视觉跟踪过程中的运动和追赶眼跳的作用类似于眼跳/漂移周期 用于静态目标。我们的所有假设都得到了初步数据的支持。据我们所知，他们完全是 它们中的任何一个都将对理解设计原则具有广泛的意义 视觉系统，可能的眼球运动对神经眼科疾病的贡献，以及 康复策略和假肢。