Colour vision: acting on an impulse.
D003118:Color Perception / Q000502:physiology*; D006801:Humans; D009900:Optic Nerve / Q000502:physiology; D010786:Photoreceptor Cells / Q000502:physiology; D012160:Retina / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology