Facing colour engineers and support corps normally had a single branch colour, although exceptionally each regiment of Swedish artillery had its own facing colour until 1910. The United States regular army after the American Civil War adopted a universal dark and light blue uniform under which each regiment was distinguished only by numbers and other insignia, plus branch colors. The latter were yellow for Cavalry, red for Artillery and white (later light blue) for infantry. Combinations of colors such as scarlet piped with white for Engineers, orange piped with white for the Signal Corps and black piped with scarlet for Ordnance personnel
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