Function of Fixational Instability During Natural Viewing

项目总结 我们的眼睛永远不会休息，即使是在关注一点的时候。我们通常不会意识到，在危险时期- 在注视的情况下，微观的眼球运动会不断地改变视网膜上的刺激。视觉感知倾向于 当刺激被人工固定在视网膜上时，就会褪色，长期以来，人们一直假设这种刺激- Sant注视运动在视觉感知中起着基础性的作用。我们最近的几个发现 美国国立卫生研究院资助的研究表明，事实上，这一运动是活跃感官的关键计算元素- 视觉系统在时间域中处理空间信息的运动策略。建立在 我们的最新结果，这个项目检查了使用眼睛的感知、计算和神经后果 在时间中表现空间的运动。它涉及三个基本问题：(目标1)空间如何 由凝视眼球运动引起的亮度调制中编码的信息？(目标2)如何 这些信息是否被提取和解释？(目标3)输入能量的时空重新分布能否 通过控制凝视眼球运动来根据任务进行调整？将定格的知觉影响联系起来 眼球运动对视觉信息神经编码的影响，阐明编码/解码机制。 这个项目融合了人类的视觉心理物理学、视网膜的统计和计算分析 输入和神经建模。实验将关键地使用一种复杂的凝视系统 显示器(已经开发并经过广泛测试)，允许精确而高度灵活地控制视网膜刺激- 发音。统计、计算和建模研究将重建和检查视觉输入信号 由视网膜感受器感受，并模拟视网膜和外侧膝状核的神经元反应。 视觉系统使用行为来代表时间中的空间，这一主张对当前的观点提出了挑战 关于早期视觉加工最基本层面的机制：它取代了传统的概念 作为被动编码阶段的视网膜，该被动编码阶段优化了与主动的信息传输的整体信息传输， 用于特征提取的可调系统，其功能只能结合眼睛运动才能理解。 这种观点的转变表明，眼球运动在一定程度上对空间视觉的基本特性负有责任 (例如，对比敏感度及其动力学)，目前完全归因于神经机制。在- 坚持注视不稳定的功能含义也可能导致新的视觉治疗方法 许多障碍的损害，其表现包括异常的注视眼球运动。

PROJECT SUMMARY Our eyes are never at rest, even when attending to a single point. We are normally not aware that, in the peri- ods of fixation, microscopic eye movements continually shift the stimulus on the retina. Visual percepts tend to fade when the stimulus is artificially immobilized on the retina, and it has long been hypothesized that the inces- sant fixational motion of the eye plays a fundamental role in visual perception. Several findings from our recent NIH-funded research suggest that this motion is, in fact, a critical computational element of an active sensori- motor strategy by which the visual system processes spatial information in the temporal domain. Building upon our recent results, this project examines the perceptual, computational, and neural consequences of using eye movements to represent space through time. It addresses three fundamental questions: (Aim 1) How is spatial information encoded in the modulations of luminance resulting from fixational eye movements? (Aim 2) How is this information extracted and interpreted? (Aim 3) Can the spatiotemporal redistribution of input energy be adjusted according to task by controlling fixational eye movements? To link the perceptual influences of fixational eye movements to their effect on the neural coding of visual information and elucidate encoding/decoding mech- anisms, this project integrates visual psychophysics in humans, statistical and computational analysis of retinal input, and neural modeling. Experiments will make critical use of a sophisticated system for gaze-contingent display (already developed and extensively tested), which allows precise, yet highly flexible control of retinal stim- ulation. Statistical, computational, and modeling studies will reconstruct and examine the visual input signals experienced by retinal receptors and simulate neuronal responses in the retina and lateral geniculate nucleus. The proposal that the visual system uses behavior to represent space through time challenges current views on the mechanisms of early visual processing at the most fundamental level: it replaces the traditional notion of the retina as a passive encoding stage that optimizes overall information transmission with that of an active, tunable system for feature extraction, whose function can only be understood in conjunction with eye movements. This shift of view implies that eye movements are in part responsible for fundamental properties of spatial vision (e.g., contrast sensitivity and its dynamics) that, at present, are solely attributed to neural mechanisms. Under- standing the functional implications of fixational instability may also lead to new treatment approaches for visual impairments in the many disorders whose manifestations include abnormal fixational eye movements.