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

描述(申请人提供)：项目摘要：我研究的长期目标是了解在许多视网膜神经节细胞的整体活动中，视网膜如何将视觉信息传递到大脑，以及在健康和疾病中，这种信号如何影响视觉感知和行为。一个尚未解决的主要问题是，灵长类视网膜中数量上占主导地位的细胞类型--侏儒、遮阳伞和小型双层细胞--是如何在空间上组织起来的，以代表视觉场景。具体地说，在我们对视觉空间感受野的镶嵌覆盖、感受野的精细结构和局部组织以及每种细胞类型内反应特性的同质性的理解上存在重大差距。我们最近完成了一种独特的512电极记录系统的合作开发，该系统能够同时测量数百个遮阳伞、侏儒和小的双层RGC在1x2 mm的视网膜区域的响应特性，使我们能够首次探索这些主要细胞类型的马赛克射频组织。我们还开发了在视网膜的基本分辨率下探测RFS结构的技术：单个视锥细胞。我们将使用这种独特的方法组合来：(1)测试侏儒和阳伞细胞RF是否以相等和独立的覆盖对视觉场景进行采样；(2)测试单个RF是否表现出交错的精细结构，从而产生更均匀的视野覆盖；以及(3)测试是否每种细胞类型都是不可还原的，或者生理亚型是否在每个马赛克中交错。 相关性：侏儒、遮阳伞和小的双层细胞约占灵长类视网膜神经节细胞的80%，它们向大脑传达了迄今为止最高敏锐度的视觉场景。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马赛克的视网膜，或者在马赛克中表现出异常可变的光反应，预计会产生退化的视觉功能。因此，了解正常的功能组织结构将有助于视力疾病的诊断。此外，目前正在人体上测试的替代视网膜功能的假体设备，最终将需要重现正常的规律性和细胞类型之间的协调，以便向大脑提供自然的视觉信号。我们最近利用多电极阵列的电刺激进行假体设计的实验，将对理解灵长类视网膜主要RGC类型的功能组织有很大帮助。总而言之，了解遮阳伞、侏儒和小双层细胞的功能组织是了解健康的视觉系统和设计因疾病损害的视网膜假体治疗的关键因素。

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.