Receptive field mosaics of midget, parasol, and small bistratified ganglion cells

描述（由申请人提供）：项目摘要：我的研究的长期目标是了解视网膜如何在许多视网膜神经节细胞的整体活动中向大脑传达视觉信息，以及这种信号传导如何影响健康和疾病中的视觉感知和行为。一个主要的未解决的问题是，灵长类动物视网膜中数量占主导地位的细胞类型-侏儒，阳伞和小型双层细胞-如何在空间上组织起来代表视觉场景。具体而言，有主要差距，我们的理解马赛克覆盖的视觉空间，其感受野（RF），精细结构和局部组织的RF，以及均匀性的响应特性内的每种细胞类型。我们最近完成了一个独特的512电极记录系统的合作开发，该系统能够同时在视网膜的1x 2 mm区域中测量数百个遮阳伞，侏儒和小型双层RGC的响应特性，使我们能够首次探测这些主要细胞类型的马赛克RF组织。我们还开发了技术，以探测视网膜的基本分辨率的RF结构：单锥。我们将使用这种独特的方法组合：（1）测试侏儒和阳伞细胞RF是否以相等和独立的覆盖范围对视觉场景进行采样;（2）测试单个RF是否表现出交叉指状精细结构，从而产生更均匀的视野覆盖范围;（3）测试每种细胞类型是否不可约，或者生理亚型是否在每个马赛克中交织。 相关性：侏儒细胞、阳伞细胞和小的双层细胞构成灵长类视网膜中约80%的神经节细胞，并且迄今为止将视觉场景的最高敏锐度表征传达给大脑。它们的功能组织对健康的视觉功能至关重要。具有退化的RF马赛克或在马赛克内显示异常可变的光响应的视网膜将预期产生退化的视觉功能。因此，了解正常的功能组织将有助于视觉疾病的诊断。此外，替代视网膜功能的假体装置目前正在人类身上进行测试，最终需要重现细胞类型之间的正常规律性和协调性，以便为大脑提供自然的视觉信号。我们最近的实验使用多电极阵列的电刺激假体设计将大大受益于了解灵长类动物视网膜中主要RGC类型的功能组织。总之，了解遮阳伞，侏儒和小型双层细胞的功能组织是了解健康视觉系统和设计疾病损伤视网膜修复治疗的关键因素。

DESCRIPTION (provided by applicant): Project Summary: The long range objective of my research is to understand how the retina conveys visual information to the brain in the ensemble activity of many retinal ganglion cells, and how this signaling influences visual perception and behavior, in health and in disease. A major unsolved problem is how the numerically dominant cell types in the primate retina - midget, parasol and small bistratified cells - are spatially organized to represent the visual scene. Specifically, there are major gaps in our understanding of the mosaic coverage of visual space by their receptive fields (RFs), the fine structure and local organization of RFs, and the homogeneity of response properties within each cell type. We have recently completed collaborative development of a unique 512-electrode recording system capable of surveying the response properties of several hundred parasol, midget and small bistratified RGCs simultaneously in a 1x2 mm region of retina, allowing us to probe the mosaic RF organization of these major cell types for the first time. We have also developed techniques to probe the structure of RFs at the elementary resolution of the retina: single cones. We will use this unique combination of approaches to: (1) test whether midget and parasol cell RFs sample the visual scene with equal and independent coverage; (2) test whether individual RFs exhibit interdigitated fine structure that produces more uniform coverage of the visual field; and (3) test whether each cell type is irreducible or whether physiological subtypes are interleaved in each mosaic. Relevance: The midget, parasol and small bistratified cells constitute ~80%of ganglion cells in the primate retina and convey by far the highest acuity representation of the visual scene to the brain. Their functional organization is crucial for healthy visual function. Retinas with degraded RF mosaics, or displaying unusually variable light responses within a mosaic, would be expected to produce degraded visual function. Therefore, understanding the normal functional organization will be useful in diagnosis of visual disease. Furthermore, prosthetic devices to replace retinal function, which are now being tested in humans, will eventually need to reproduce the normal regularity and coordination between cell types in order to provide natural visual signals to the brain. Our recent experiments using electrical stimulation with multi-electrode arrays for prosthetic design will benefit greatly from understanding the functional organization of the major RGC types in primate retina. In summary, knowing the functional organization of parasol, midget and small bistratified cells is a key element in understanding the healthy visual system and designing prosthetic treatments for retinas damaged by disease.