Colour centre in humans as an area specialized for colour vision. V2, also called the prestriate cortex, is believed to have a small role in colour processing by projecting signals from V1 to the V4-complex. Whether or not colour selective cells are present in V2 is still being investigated. Some optical imaging studies have found small clusters of red-green colour selective cells in V1 and V2, but not any blue-yellow colour selective cells. Other studies have shown that V2 is activated by colour stimuli, but not colour after images.[8] V4 also has feedback on V2, suggesting that there is a defined network
Colour recovery frequency, known as the "colour subcarrier". Black and white televisions do not decode this extra colour information in the subcarrier, using only the luminance to provide a monochrome picture. However, due to limited bandwidth in the video channel, the chrominance and luminance signals bleed into each other considerably, resulting in the colour information showing up visibly as Chroma Crawl, or Chroma dots on black & white TV sets. This is normally considered a nuisance in analogue broadcasting. However, since telerecordings were made from black & white TV screens and technicians at the time often decided not to apply a filter