Tetrachromacy class eventually lose two of their four cones. The normal explanation of tetrachromacy is that the organism's retina contains four types of higher-intensity light receptor (called cone cells in vertebrates as opposed to rod cells, which are lower intensity light receptors) with different absorption spectra. This means that the animal may see wavelengths beyond those of a typical human being's eyesight, and may be able to distinguish between colors that, to a normal human, appear to be identical. Species with tetrachromatic color vision may have an unknown physiological advantage over rival species. The goldfish ("Carassius auratus auratus") and zebrafish ("Danio
AII amacrine cells AII amacrine cells AII amacrine cells are a subtype of amacrine cells present in the retina of mammals. AII amacrine cell serve the critical role of transferring light signals from rod photoreceptors to the retinal ganglion cells (which contain the axons of the optic nerve) The Classical Rod Pathway described the role of AII amacrine cells in the mammalian retina. This can be summarised as follows: (Once activated, the AII amacrine cell then modulates the cone ON and OFF channels): The ON- and OFF- cone bipolar cells in turn contact the ON- and OFF-centre retinal ganglion cells, respectively. "Note: A