or it is a characteristic possessed by very few mammals. K. Tansely in one of his books on the visual system and vision in vertebrates commented that "On the whole mammals appear to have no color vision, except in primates where it is well developed and almost certainly trichomatic". The word trichomatic derives from a theory formulated by the French physiologist Palmer in 1777 which stated the presence of three different types of an infinite number of molecules present in the human retina. These types are for detecting colors such as red, blue and yellow. A few years later Thomas Young postulated the presence of three types of cones responsible for detecting these primary colors or metamers and their concept was demonstrated empirically by Maxwell in 1860. This trichomatic nature of human retinal perception seemed like a limitation as the eye human can perceive millions of colors. These millions of colors are limited to Grassman's laws which explain the additive, scalar and associative properties of metamers to demonstrate the different color combinations perceived by the visual system. The human range of light perception is from 380 nm to 760 nm. Color perception depends on the ability of photoreceptors to separate different wavelengths. Bowmaker et al in 1979 were able to identify the cone using microspectrometry by observing the absorption spectrum of the cone. The cones were in the blue, green and red spectrum with a wavelength of 420 nm, 534 nm and 564 nm. The identified rod absorbed the spectrum at 498 nm. The results on the absorption spectrum were quite similar to the results found on the rhesus monkey by the same author.*Bowmaker et al. The names given to the cones on the absorption spectrum are S (short), L (long), and (M) moderate. T...... middle of paper ...... cells of the gnocellular pathway are shown by the gray cells. (Martin 2004) The third and smallest layer is koniocellular which is present between the parvocellular and magnocellular and consists mainly of inter-neurons. Blue-ON cells form a connection with small bistratified ganglion cells and ends in Koniocellular cells. These small neurons project to supragranular layers 2, 3, and upper 4, including the cytochrome oxidase-rich “blob” region of the visual cortex.*The sampling density of blue-ON cells relative to the S-cone matrix is shown by white circles.( *Martin 2004) There is an unknown pathway starting from yellow-ON ganglion cells with large receptive field and ending with an unknown destination in the lateral geniculate nucleus. *The small white circle at the S cone location represents the postulated blue-OFF dwarf ganglion cells. . (Martin 2004)

Topic > or it is a characteristic possessed by very few mammals. K. Tansely in one of his books on the visual system and vision in vertebrates commented that "On the whole mammals appear to have no color vision, except in primates where it is well developed and almost certainly trichomatic". The word trichomatic derives from a theory formulated by the French physiologist Palmer in 1777 which stated the presence of three different types of an infinite number of molecules present in the human retina. These types are for detecting colors such as red, blue and yellow. A few years later Thomas Young postulated the presence of three types of cones responsible for detecting these primary colors or metamers and their concept was demonstrated empirically by Maxwell in 1860. This trichomatic nature of human retinal perception seemed like a limitation as the eye human can perceive millions of colors. These millions of colors are limited to Grassman's laws which explain the additive, scalar and associative properties of metamers to demonstrate the different color combinations perceived by the visual system. The human range of light perception is from 380 nm to 760 nm. Color perception depends on the ability of photoreceptors to separate different wavelengths. Bowmaker et al in 1979 were able to identify the cone using microspectrometry by observing the absorption spectrum of the cone. The cones were in the blue, green and red spectrum with a wavelength of 420 nm, 534 nm and 564 nm. The identified rod absorbed the spectrum at 498 nm. The results on the absorption spectrum were quite similar to the results found on the rhesus monkey by the same author.*Bowmaker et al. The names given to the cones on the absorption spectrum are S (short), L (long), and (M) moderate. T...... middle of paper ...... cells of the gnocellular pathway are shown by the gray cells. (Martin 2004) The third and smallest layer is koniocellular which is present between the parvocellular and magnocellular and consists mainly of inter-neurons. Blue-ON cells form a connection with small bistratified ganglion cells and ends in Koniocellular cells. These small neurons project to supragranular layers 2, 3, and upper 4, including the cytochrome oxidase-rich “blob” region of the visual cortex.*The sampling density of blue-ON cells relative to the S-cone matrix is shown by white circles.( *Martin 2004) There is an unknown pathway starting from yellow-ON ganglion cells with large receptive field and ending with an unknown destination in the lateral geniculate nucleus. *The small white circle at the S cone location represents the postulated blue-OFF dwarf ganglion cells. . (Martin 2004)