Color Information Processing in Higher Brain Areas

Significant color signal transformation occurs in the primary visual cortex and neurons tuned to various direction in the color space are generated. The resulting multi-axes color representation appears to be the basic principle of color representation throughout the visual cortex. Color signal is conveyed through the ventral stream of cortical visual pathway and finally reaches to the inferior temporal (IT) cortex. Lesion studies have shown that IT cortex plays critical role in color vision. Color discrimination is accomplished by using the activities of a large number of color selective IT neurons with various properties. Both discrimination and categorization are important aspects of our color vision, and we can switch between these two modes depending on the task demand. IT cortex receives top-down signal coding the task and this signal adaptively modulates the color selective responses in IT cortex such that neural signals useful for the ongoing task is efficiently selected.