Cerebral lateralization and color perception: a transcranial Doppler study.

Eight normal subjects were examined in dark, light and color conditions. Mean cerebral blood flow velocity (MBFV) were recorded almost simultaneously from their posterior cerebral arteries (PCA) using transcranial Doppler (TCD) ultrasound. The side-to-side difference was significant during the dark (p = 0.0159) and color stimulation (p = 0.0001) but not in light condition. This side-to-side difference in MBFV was used to characterize lateralization of color perception. This showed that the right PCA was always greater than the left during the presentation of color stimuli. Primary psychological colors (blue, yellow, red and green) induced greater lateralization as compared with color resulting from a mixed blue-green wavelength. This suggests that the right visual cortex is selectively sensitive to wavelengths.