Abstract
It is known that the interaction between brightness and color generates different color appearance for the same object. For example, an object is most colorful when its brightness is the same as the brightness of its surroundings. As the brightness difference between object and surround increases, the color appearance of the object weakens. However, it is not clear yet where in the cerebral cortex brightness-color interaction takes place. One possibility is that brightness and color signals are processed separately within V1 and only interact in higher visual cortex beyond the primary visual cortex (V1). Another possibility is that color and brightness contrast interact within V1. We localized the brightness-color interaction in V1 by means of recording the human chromatic visual evoked potential, the cVEP. We found that the cVEP was maximal when brightness contrast between color target and surround was zero. The behavior of cVEP from V1 decisively supports the idea that brightness-color interaction arises in a recurrent network in V1 in a winner-take-all manner. Furthermore, we also found that the color and brightness contrast at the edges between color target and surroundings are powerful determinants of perceived color as well as the cVEP. Recurrent inhibition in local cortical circuits has been called a canonical cortical computation and we show that this canonical computation implemented in V1 cortex has a strong influence on color perception.
Meeting abstract presented at VSS 2014