MULTINEURONAL SIGNALING BY THE RETINA

这个研究项目旨在详细了解眼睛是如何 向大脑传递视觉信息。 功能研究 视网膜主要决定了单个神经元的特性， 他们的突触连接，而相对较少的是知道如何 特定细胞的活动与其他细胞的活动在时间上相关。 然而 大脑中的视觉中心利用同步放电的模式 在大量的视网膜神经节细胞中， 我们视觉环境的重要特征。 因此，最终目标 这项工作的目的是精确地确定视网膜是如何编码一个 通过神经节细胞的电活动模式来观察视觉场景 层. 这项工作的重点是视觉信息的表示， 一群神经元，而不是单个细胞。 在这些实验中，虎蝾螈的视网膜被放置在 在具有许多嵌入式金属微电极的玻璃表面上，覆盖 面积约0.2mm（2）。 视网膜神经节细胞位于 接近电极阵列，使得每个部位记录 由附近的一些神经元产生的细胞外动作电位。 因此，在本发明中， 可以同时监测多达100个 神经节细胞 视网膜受到感官输入的刺激， 将来自计算机监视器的图像投影到感光体层上。 这些方法将用于以下具体项目： (1)神经节细胞功能特性的研究进展 视网膜。 这项研究将确定细胞之间的数量比例 不同的反应类型，无论它们是在空间上排列， 有组织的模式，以及它们的分布与 从视觉刺激中提取的信息。 (2)不同脑区神经元放电模式的相关性研究 神经节细胞 这些神经元通常与它们的 活动，并参与协调一致的射击模式，只能是 通过多电极记录观察。 这些分布式的发射 图案传达视觉信息？ (3)一项关于视觉刺激的特征如何被 从记录的神经节细胞尖峰序列估计。 目标是 构建一个算法，可以解释视网膜输出，以提供 视觉输入的重建。 这将揭开 并提出如何在随后的视觉中心电路 可以执行类似的特征检测任务。 这些研究将揭示集体职能的重要方面， 视网膜的回路 结果将提供一个更好的理解 以及大脑如何表达和处理信息。 最终，这可能会改善检测和治疗 视觉缺陷，并在遥远的未来，视觉的发展， 可以模拟视网膜功能的假体。

This research project aims for a detailed understanding of how the eye signals visual information to the brain. Functional investigations of the retina have primarily determined the properties of single neurons and their synaptic connections, while comparatively little is known about how a given cell's activity correlates in time with that of others. Yet the visual centers in the brain draw on the pattern of simultaneous firing in a large population of retinal ganglion cells in order to detect important features of our visual environment. Thus, the ultimate goal of the proposed work is to determine precisely how the retina encodes a visual scene by the patterns of electrical activity in the ganglion cell layer. The work focuses on the representation of visual information in a population of neurons, rather than individual cells. In these experiments, the isolated retina of a tiger salamander is placed on a glass surface with many embedded metal microelectrodes, covering an area of about 0.2mm(2). The retinal ganglion cells lie in close proximity to the electrode array, such that each site records extracellular action potentials generated by a few nearby neurons. Thus, one can monitor simultaneously the electrical signals from up to 100 ganglion cells. The retina is stimulated with sensory input by projecting an image from a computer monitor onto the photoreceptor layer. These methods will be used in the following specific projects: (1) A survey of the functional properties of ganglion cells in the retina. This study will determine the numerical proportions among cells of different response types, whether they are arranged in a spatially organized pattern, and how their distribution relates to the type of information they can extract from the visual stimulus. (2) A study of correlations between the firing patterns of different ganglion cells. These neurons are often strongly correlated in their activity, and participate in modes of concerted firing that can only be observed by multielectrode recording. Do these distributed firing patterns convey visual information? (3) An investigation of how features of the visual stimulus might be estimated from the recorded ganglion cell spike trains. The goal is to construct an algorithm that can interpret the retinal output to provide a reconstruction of the visual input. This will uncover the structure of the retinal code and suggest how circuits at subsequent visual centers might perform similar tasks of feature detection. These studies will reveal important aspects of collective function in the circuits of the retina. The results will provide a better understanding of how we see, and how the brain represents and processes information. Ultimately, this may lead to improvements in detecting and treating visual deficiencies, and, in the far future, to the development of visual prostheses that can emulate the function of the retina.