The Organization of the Retina and Visual System
Yves Sauve and Frederic Gallard 1. Introduction “…once development was ended, the founts of growth and regeneration of the axons and dendrites dried up irrevocably. In adult centres the nerve paths are something fixed, ended, immutable. Everything may die, nothing may be regenerated. It is for the science of the future to change, if possible, …
Sam Nona 1. Overview. The visual system of the goldfish has been the subject of intensive studies for over a quarter of a century. It differs from the visual system of most other vertebrates, including mammals, in that it continues to grow by the addition of new neurons throughout much of the animal’s …
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Matthew Schmolesky The human visual system can detect and discriminate between an incredibly diverse assortment of stimuli that may be chromatic or achromatic, in motion or not, pattered or unpatterned, two-dimensional or three. Remarkably, the neural end-product of visual stimuli impacting upon the retina is, in one sense, always the same. After the complexities …
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Michael Kalloniatis and Charles Luu Dark Adaptation. The eye operates over a large range of light levels. The sensitivity of our eye can be measured by determining the absolute intensity threshold, that is, the minimum luminance of a test spot required to produce a visual sensation. This can be measured by placing a …
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The eye can function over a large range of luminance levels; it must also be able to handle the different rates of change in luminance. Our eyes are constantly sampling information of images projected onto the retina in a periodic manner. Information is then integrated so objects around us appear to be stable or move …
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Peter Gouras 1. Introduction. Color vision is an illusion created by the interactions of billions of neurons in our brain. There is no color in the external world; it is created by neural programs and projected onto the outer world we see. It is intimately linked to the perception of form where color …
Kevin J. Ford and Marla Feller Introduction The mammalian retina has long been a model system for study of development of neural circuits in the CNS because the adult network is well organized into cell-type specific layers, and the anatomy, physiology and function of many of the retinal cell types is well characterized. A …
Josh Morgan and Rachel Wong 1. Introduction. Synaptic connections of the vertebrate retina are organized into distinct laminae (Figure 1). In the outer retina, photoreceptors contact horizontal cells and bipolar cells within a single lamina, the outer plexiform layer (OPL). Within the inner retina, synapses between retinal ganglion cells and their presynaptic partners, the …
Haohua Qian Properties of GABA receptors GABA (g-aminobutyric acid) is the main inhibitory neurotransmitter in the central nervous system. The inhibitory action of GABA is mediated by the receptors present on the cell membrane, and results in a reduction of neuronal excitablity. At least three types of GABA receptors have been characterized. Table 1 summarizes …
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Victoria Connaughton 1. General overview of synaptic transmission. Cells communicate with each other electrically, through gap junctions, and chemically, using neurotransmitters. Chemical synaptic transmission allows nerve signals to be exchanged between cells which are electrically isolated from each other. The chemical messenger, or neurotransmitter, provides a way to send the signal across the extracellular space, …
Helga Kolb 1. General characteristics. At every level of the retina there are reciprocal or feed-back loops in the circuitry so that certain neurons can interact laterally within the same layer, vertically from one layer to the other and indeed from the brain to the retina. The intra-layer feed-back loops are typically provided …
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 …
Ralph Nelson 1. Overview. Ganglion cells are the final output neurons of the vertebrate retina. Ganglion cells collect information about the visual world from bipolar cells and amacrine cells (retinal interneurons). This information is in the form of chemical messages sensed by receptors on the ganglion cell membrane. Transmembrane receptors, in turn, transform …
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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Helga Kolb 1. Bipolar, amacrine and ganglion cells interact in the inner plexiform layer. The axonal endings of bipolar cells bring information from the outer plexiform layer (OPL) to the neuropil of the inner plexiform layer (IPL). Here bipolar cells talk to different varieties of functionally specialized amacrine cells and to dendrites of …