Mahnoosh Farsaii and Victoria P. Connaughton 1. Introduction. The AII amacrine cell is characterized by a multifaceted connectivity and physiology. It is unique among amacrine cells in that it participates predominantly in the vertical flow of information though the inner retina, contributing to center mechanisms, rather than in lateral inhibitory pathways. As its multilayer …
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Helga Kolb 1. General characteristics. Amacrine cells of the vertebrate retina are interneurons that interact at the second synaptic level of the vertically direct pathways consisting of the photoreceptor-bipolar-ganglion cell chain. They are synaptically active in the inner plexiform layer (IPL) and serve to integrate, modulate and interpose a temporal domain to the …
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Helga Kolb 1. Rods. Rod photoreceptors and rod-connected nerve cells through the retina are responsible for pathways concerned with night vision and increased sensitivity of our visual system under what is called scotopic conditions (conditions of very little ambient light). Most vertebrates have a preponderance of rod photoreceptors in their retinas and such …
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Helga Kolb Three basic types of glial cell are found in the human retina, Muller cells, astroglia and microglia. All were described for the retina by Cajal more than one hundred years ago (1892). 1. Muller cells. Muller cells are the principal glial cell of the retina. They form architectural support structures stretching …
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1Dustin M. Graham and 2,3Kwoon Y. Wong 1Nature Publishing Group, New York, NY. 2Department of Ophthalmology & Visual Sciences, Department of Molecular, Cellular & Developmental Biology, University of Michigan, Ann Arbor, MI 48105. 3Correspondence: kwoon@umich.edu 1. Introduction. For the greater part of 150 years it was assumed that the mammalian retina contained only …
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Helga Kolb 1. General morphology. Ganglion cells are the final output neurons of the vertebrate retina. The ganglion cell collects the electrical messages concerning the visual signal from the two layers of nerve cells preceding it in the retinal wiring scheme. A great deal of preprocessing has been accomplished by the neurons of …
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Ido Perlman, Helga Kolb and Ralph Nelson 1. Introduction Horizontal cells are the interneurons of distal vertebrate retina. They provide the pathways for both local and long range interactions between photoreceptors. These interactions are called feedback signals. Feedback signals adjust the gain of photoreceptor synaptic output, both as seen in the horizontal cells themselves …
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Olaf Strauss 1. Introduction. The simplest light detecting organs are composed of two cell types: the light sensitive photoreceptor cell and the pigmented cell. Both cell types appear in conjunction in every eye of the animal kingdom from insects, mollusca to higher vertebrates [1]. Interactions between both the pigmented cells and the photoreceptor cells are …
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Use/Permissions: For non-commercial, academic purposes, images and content from the chapters portion of Webvision may be used with a non-exclusive rights under a Attribution, Noncommercial 4.0 International (CC BY-NC) Creative Commons license. Cite Webvision, http://webvision.med.utah.edu/ as the source. About the Authors: Dr. Helga Kolb was born and educated in England receiving B.Sc., M.Sc. and Ph.D. …
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1. Size of the retina. 32 mm from ora to ora along the horizontal meridian (Van Buren, 1963; Kolb, unpublished measurements). Area of the human retina is 1094 square mm (Bernstein, personal communication) calculated from the expectations that the average dimension of the human eye is 22 mm from anterior to posterior poles, and …
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Helga Kolb 1. General characteristics. Todays research on the retina focuses a great deal of attention on neurotransmission between the neurons of the retina. Varous techniques using autoradiography, immunocytochemistry and molecular biology are being used to mark neurons for neurochemicals, their synthesizing enzymes, calcium binding proteins and receptors and transporters of these neurochemicals. …
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