Abstract
We examined color contrast adaptation to see if the chromatic pattern-onset VEP reflects either narrowly tuned, color processing or lower level, broad-band color tuning. Chromatic contrast adaptation was assessed by measuring changes in the VEP response following patterned adaptation along cardinal and intermediate axes in MBDKL color space. Isoluminant settings were found for each participant through a minimum motion paradigm. Individual contrast thresholds were measured psychophysically along cardinal axes and all VEP stimulus contrasts were equated to be equal multiples of threshold for each subject. Results were consistent with psychophysical data and showed evidence for selective adaptation to both cardinal and orthogonal chromatic axes. There were individual differences in the degree to selectivity. Results suggest that the chromatic VEP reflects more narrowly tuned, higher-order color processing, beyond that of the opponent mechanisms.