Processing of spatial information in V1 through fixational eye movements

项目摘要 这个项目的重点是大脑皮层机制的信息处理的作用注视眼 视觉运动（FEM）。FEM，眼睛的微观“抖动”，不断出现时， 凝视没有被转移-长期以来一直被认为是一个“错误”，即，这一定是模糊的根源 克服但基于与米歇尔·鲁奇实验室的合作，现在很明显，这种抖动不是一种 bug，而是一个特征，即，一个关键的信息处理步骤。固视的具体特征 眼球运动允许在时域中有效地表示空间信息，允许稍后的神经 处理使用动态，如神经同步，以提取视觉特征。这种根本性的转变 观点有许多重要的影响，包括：（i），因为注视眼运动是在眼动下进行的， 控制，它们提供了一种机制，通过这种机制，视觉系统的属性可以根据任务进行调整， (ii)，因为FEM的正常模式对于正常的视觉敏感度是必不可少的，与疾病和年龄相关， 眼功能的改变必然导致先前认为的视觉感知的改变， 是纯粹的感官起源。 我们以前的工作通过知觉实验建立了注视眼动的重要性， 人和建模研究，但没有提供生理基础的知识。在目标1中， 建立一个非人类灵长类系统，使我们能够获得这些知识，在目标2中，我们将用它来 解决有关机制的根本问题。具体来说，在目标1中，我们将整合几个 我们和我们的合作者都是专家，但从未结合的技术，包括： 在猕猴视皮层植入慢性高密度记录阵列， 分辨率眼睛跟踪系统的基础上巩膜线圈，定制的视觉显示系统的建设，能够 基于这些线圈信号，选择性地稳定视觉图像的部分， 用于逐个试验比较性能，并离线重建感受野和位置， 以比单独使用巩膜线圈更高的分辨率移动眼睛。在目标2中，我们将使用 在全视网膜成像和部分视网膜成像条件下，在视觉辨别任务期间从V1记录的系统 稳定化这些实验将确定（a）FEM是否通过以下方式支持高敏锐度视力： 亮度瞬变的产生，以及（B）传出复制和/或运动规划信号是否是必要的 来利用这些信息。我们的总体假设是，亮度瞬变产生不同的时间 V1神经元的活动模式，这些时间模式是高敏锐度视觉的基础。 更广泛地说，视觉系统使用视觉行为来表示空间， 时间意味着视觉是一个积极的过程，更类似于其他感官（如躯体感觉），而不是 这是一个概念上的转变，对研究视觉功能和功能障碍有重要意义。

PROJECT SUMMARY This project focuses on cortical mechanisms underlying the information-processing roles of fixational eye movements (FEM's) in vision. FEM's, the microscopic “jittering” of the eyes that is constantly present when gaze is not being shifted – have long been regarded as a “bug”, i.e., a source of blurring that must be overcome. But based on work in collaboration with Michele Rucci's lab, it is now clear that this jittering is not a bug, but rather, a feature, i.e., a crucial information-processing step. The specific characteristics of fixational eye movements allow for efficient representation of spatial information in the time domain, allowing later neural processing to use dynamics, such as neural synchrony, to extract visual features. This fundamental shift in viewpoint has many important implications, including: (i), since fixational eye movements are under oculomotor control, they provide a mechanism by which the visual system's properties can be tuned according to task, and (ii), since the normal pattern of FEM's is essential for normal visual sensitivity, disease- and age-related changes in oculomotor function necessarily lead to alterations in visual perception that were previously thought to be purely sensory in origin. Our previous work establishes the importance of fixational eye movements via perceptual experiments in man and modeling studies, but provides no knowledge of the physiological underpinnings. In Aim 1 we will establish a non-human primate system that will enable us obtain this knowledge, and in Aim 2, we will use it to address fundamental questions concerning mechanism. Specifically, in Aim 1 we will integrate several technologies that we and our collaborators are experts in, but which have never been combined, including: implantation of chronic high-density recording arrays in macaque visual cortex, construction of a high- resolution eye tracking system based on scleral coils, construction of a custom visual display system capable of selectively stabilizing portions of a visual image based on these coil signals, online analysis of neural activity for trial-by-trial comparison with performance, and offline reconstruction of receptive fields and the position and movement of the eyes at a higher resolution than possible with scleral coils alone. In Aim 2, we will use this system to record from V1 during visual discrimination tasks, under conditions of full and partial retinal image stabilization. These experiments will determine whether (a) FEM's act to support high acuity vision via generation of luminance transients, and (b) whether efferent-copy and/or motor-planning signals are necessary to make use of this information. Our overall hypothesis is that the luminance transients create distinct temporal patterns of activity in V1 neurons, and that these temporal patterns underlie high-acuity vision. More broadly the proposal that the visual system uses oculomotor behavior to represent space through time implies that vision is an active process, more analogous to other senses (e.g. somatosensation) than commonly postulated, a conceptual shift with major implications for studying visual function and dysfunction.