Colour contrast is detected much earlier in the brain than previously thought, a new study shows. Scientists at Durham University have confirmed that colour contrast is first detected by part of the brain called primary visual cortex, which is located at the very back of the head where visual information first enters the cortex of the brain.
This was recently discovered to be the case in animals but has not been tested on human beings until now.
The research also confirms that the brain does most of the work in seeing the difference between colours, rather than the eye.
The team of neuropsychologists identified a patient with damage to this specific part of the brain. They showed the patient visual illusions in which the contrast between the coloured spots in the foreground and their background colour affected the way the spots looked. People with this part of the brain intact would see the spots as different as they look different on varying backgrounds. The patient was not able to detect that difference.
The research, which is published in the Proceedings of the National Academy of Sciences this week, makes a significant contribution to the understanding of how the brain functions.