Isabelline (colour) form of leucism caused by a uniform reduction in the production and expression of melanin resulting in areas of plumage on the back of the bird, normally black, being strongly faded, or isabelline, in appearance. Isabellinism has been reported in several species of penguin. Isabelline and isabella are terms applied in Europe to very pale palomino or cremello horses, animals with a coat colour that is variously described as cream, pale gold or almost white; this is the primary usage of the French ("isabelle") and German ("Isabella") versions of the word. In horses, this colour is created by the action
Colour centre the recognition of shapes, motion, and colour. V1 has multiple areas that are colour-sensitive, which indicates that colour processing is not limited to one area. According to a paper by Dr Robert Shapley, V1 has an important role in colour perception. fMRI experimental results showed that V1 has two kinds of colour sensitive neurons: single-opponent and double-opponent cells. These cells are integral in the opponent process of interpreting colour signals. Single-opponent neurons respond to large areas of colour. This is advantageous for recognizing large colour scenes and atmospheres. In comparison, double opponent cells respond to patterns, textures, and colour boundaries.