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
Eye cells used for vision: the rods and the cones. Rods cannot distinguish colours, but are responsible for low-light (scotopic) monochrome (black-and-white) vision; they work well in dim light as they contain a pigment, rhodopsin (visual purple), which is sensitive at low light intensity, but saturates at higher (photopic) intensities. Rods are distributed throughout the retina but there are none at the fovea and none at the blind spot. Rod density is greater in the peripheral retina than in the central retina. Cones are responsible for colour vision. They require brighter light to function than rods require. In humans, there are