Cones and Color Vision

Cones and Color Vision - * Right geniculate body receives...

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Anatomy of the Eye Cones and Color Vision * Eachtype of cone contains retinene associated with photopsins. * Photopsin protein is unique for each of the 3 cone pigments. * Each cone absorbs different wavelengths of light. Visual Acuity and Sensitivity * Each eye oriented so that image falls within fovea centralis. * Fovea only contains cones. * Degree of convergence of cones is 1:1. * Peripheral regions contain both rods and cones. * Degree of convergence of rods is much lower. * Visual acuity greatest and sensitivity lowest when light falls on fovea. Neural Pathways from Retina * Right half of visual field project to left half of retina of both eyes. * Left half of visual field project to right half of retina of both eyes. * Left geniculate body receives input from both eyes from the right half of the visual field.
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Unformatted text preview: * Right geniculate body receives input from both eyes from left half of visual field. * Neurons project to striate cortex. Eye Movements * Superior colliculus coordinate: * Smooth pursuit movements: * Track moving objects. * Keep image focused on the fovea. * Saccadic eye movements: * Quick jerky movements. * Occur when eyes appear still. * Move image to different photoreceptors. Neural Processing of Visual Information * Receptive field: * Part of visual field that affects activity of particular ganglion cell. * On-center fields: * Responses produced by light in the center of visual fields. * Off-center fields: * Responses inhibited by light in the center and stimulated by light in the surround....
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