The Organization of the Retina and Visual System
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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By Helga Kolb, Ralph Nelson, Peter Ahnelt, Isabel Ortuño-Lizarán and Nicolas Cuenca Abstract We summarize the development, structure, different neural types and neural circuitry in the human fovea. The foveal pit is devoid of rod photoreceptors and of secondary and tertiary neurons, allowing light to directly stimulate cones and give us maximal visual acuity. The …
Stuart Trenholm1 and Gautam B. Awatramani2 1Assistant Professor, Montreal Neurological Institute, McGill University, Montreal, Canada: stuart.trenholm@mcgill.ca 2Associate Professor, Department of Biology, University of Victoria, Victoria, Canada: gautam@uvic.ca Abstract Gap junctions are recognized in the electron microscope as dense starchy areas of opposed membrane between two cells. Small tracer molecules such as Neurobiotin pass through the …
1. Introduction The ability to detect moving objects in the visual scene is fundamental to our daily survival. It originates within the sensory organ, the retina, where a significant proportion of retinal ganglion cell (RGC) responses is dedicated to detecting motion in different directions (Fig.1). The first evidence for such retinal computation …
Bryan William Jones, Robert E. Marc and Rebecca L. Pfeiffer 1. Introduction Retinal degeneration and remodeling encompasses a group of pathologies at the molecular, cellular and tissue levels that are initiated by inherited retinal diseases like retinitis pigmentosa (RP), genetic and environmental diseases like age-related macular degeneration (AMD) and other insults to the eye/retina …
1 Introduction “Nothing in biology makes sense except in the light of evolution” (1). Theodosius Dobzhansky’s insight is especially apposite in trying to comprehend the nature of our rod and cone photoreceptors, and the organization of our retina. Unless we understand how these cells and structures arose, through hundreds of millions of years of evolution, …
Ning Tian Introduction The neuronal information of the visual scene that is processed by the retina is conducted to the brain by a set of separate spatio-temporal synaptic pathways. The morphological basis for the formation of these parallel synaptic pathways is the laminar-specific structure of the retina, in which specific subtypes of retinal neurons …
Steve Fisher, Geoffrey P. Lewis, Kenneth A Linberg, Edward Barawid and Mark V. Verardo 1. Introduction. What is retinal detachment? The retina is firmly attached to the apical surface of the retinal pigmented epithelium, or RPE (see earlier retinal anatomy sections). When the retina is separated from its normal position apposed to the …
Frederic Gaillard and Yves Sauve 1. Introduction Injury to the brain areas concerned with vision can cause a variety of disorders ranging from visual field defects to much more complex deficits like visual agnosia. It all depends on the location and the extent of the damage. Injury to the occipital striate cortex results in corresponding …
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, …
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 …
Ralph Nelson and Victoria Connaughton 1. Introduction. Retinal ganglion cells are typically only two synapses distant from retinal photoreceptors, yet ganglion cell responses are far more diverse than those of photoreceptors. The most direct pathway from photoreceptors to ganglion cells is through retinal bipolar cells. Thus, it is of great interest to understand how bipolar …
Helga Kolb 1. General characteristics. The specialized cone pathways of the central fovea of human and monkey retinas have the least convergence and the greatest resolution capabilities of the visual system. This is accomplished by making the connections as “private” as possible and narrowing them to a one to one relationship in the …
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 …