Colour centre This is more important for perceiving the colour of objects and pictures. The double-opponent cells are receptive to opposite inputs from different cone cells in the retina. This is ideal for identifying contrasting colours, such as red and green. [1] Double-opponent cells are particularly important in computing local cone ratios from visual information from their receptive fields. Single opponent colour-sensitive neurons can be divided into two categories depending on the signals they receive from the cone cells: L-M neurons and S/(L+M) neurons. The three types of cone cells, small (S), medium (M), and long (L), detect different wavelengths across the
Helmethead gecko are flattened and spatulate. Helmethead geckos can be anywhere from light grey to dark brown, either uniform in color or with pale or dark blotches. The underside of the gecko is light-colored. This gecko is mainly nocturnal, and whereas most lizards are diurnal and have lost the rod structures in the retina that is typical of vertebrates, retaining only cones, this gecko has further adapted its eyes so that it has some degree of color vision at night. The gecko has developed a multifocal optical system which enables it to distinguish between light at different wavelengths. The pupils of this