Evolution of human colour vision that are found between 450 and 625. Individuals with various forms of colour blindness such as deuteranopia and protanopia are missing human middle wavelength sensitive or long wavelength sensitive opsins. Their minimum wavelength differences are <5 but only at around 500. Protanopes, who are missing long wavelength sensitive cones, are unable to distinguish between colours in the green-yellow-red section of the electromagnetic spectrum. They find yellow, red and orange colours to have much lower brightness when compared to a trichromat. The dimming of these colours can result in confusion in many cases, such as when attempting to identify red traffic
Colour centre colour centre begins in V1 and sends signals to extrastriate areas V2 and V4 for further processing. V4 in particular is an area of interest because of the strength of the colour receptive fields in its neurons. V4 was initially identified in macaque monkey visual cortex experiments. Originally, it was proposed that colour was selectively processed in V4. However, this hypothesis was later rejected in favour of another hypothesis which suggested that V4 and other areas around V4 work together to process colour in the form of multiple colour selective regions. After identification of V4 as the colour-selective region in