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Color vision, a feature of visual ... Color perception is a part of the larger visual system and is mediated by a complex process between neurons that begins with ...
Trichromatic color vision is the ability of humans and some other animals to see different colors, mediated by interactions among three types of color-sensing cone cells. The trichromatic color theory began in the 18th century, when Thomas Young proposed that color vision was a result of three different photoreceptor cells.
While color vision is dependent on many factors, discussion of the evolution of color vision is typically simplified to two factors: the breadth of the visible spectrum (which wavelengths of light can be detected), and; the dimensionality of the color gamut (e.g. dichromacy vs. tetrachromacy).
The rate of firing of the ganglion cells is increased when it is signaled by one cone and decreased (inhibited) when it is signaled by the other cone. The first color in the name of the ganglion cell is the color that excites it and the second is the color that inhibits it. i.e.:
Researchers studying the opsin genes responsible for colour-vision pigments have long known that four photopigment opsins exist in birds, reptiles and teleost fish. [3] This indicates that the common ancestor of amphibians and amniotes (≈350 million years ago) had tetrachromatic vision — the ability to see four dimensions of colour.
As opsin molecules were tuned to detect different wavelengths of light, at some point color vision developed when the photoreceptor cells used differently tuned opsins. [29] This may have happened at any of the early stages of the eye's evolution, and may have disappeared and reevolved as relative selective pressures on the lineage varied.
Finally, a person with hemiachromatopsia see half of their field of vision in colour, and the other half in grey. The visual hemifield contralateral to a lesion in the lingual or fusiform gyrus is the one that appears grey, while the ipsilateral visual hemifield appears in colour. [ 13 ]
Opponent-process theory is a psychological and neurological model that accounts for a wide range of behaviors, including color vision. This model was first proposed in 1878 by Ewald Hering , a German physiologist, and later expanded by Richard Solomon , a 20th-century psychologist.