Visual neurobiology: Colouring the cortex

At the neural level, our perception of colour is due to a group of so-called ‘colour-opponent’ neurons, which receive inputs from the three different classes of cone photoreceptors that are found in the eye. These neurons were thought to operate during the first stages of visual processing but, using functional magnetic resonance imaging (fMRI), they have now been shown to be active at higher levels of the visual cortex.