The finger in flight: Real-time motor control by visually masked color stimuli

Current theories of dual visual systems suggest that color is processed in a ventral cortical stream that eventually gives rise to visual awareness but is only indirectly involved ill Visuomotor control mediated by the dorsal stream. If the dorsal stream is indeed less sensitive to color than the ventral stream, color stimuli blocked from awareness by visual masking should also be blocked from guiding fast motor responses. In this study, pointing movements to one of two isoluminant color targets were preceded by consistent or inconsistent color primes. Trajectories were strongly affected by printing, with kinematics implying a continuous flow of color information into executive brain areas while the finger was already, moving. Motor effects were more sensitive to color of the primes than were deliberate attempts to identify the primes ill forced-choice tasks based on visual awareness. Priming was observed even when masking was complete.