cone

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cone In a vertebrate eye, the less common (compare ROD) of the two types of light-receptor cell, which is sensitive only to relatively high levels of stimulation. Many cones are connected each to a single bipolar cell and thence to a ganglion cell whose axon forms a nerve fibre in the optic tract. Since cones respond only to high levels of stimulation and since each stimulation produces an individual nerve impulse, cones provide sharp images.

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