Implicit visuomotor processing for quick online reactions is robust against aging.

It is well established that humans can react more quickly to a visual stimulus in the visual field center than to one in the visual periphery and that the reaction to a stimulus in the visual periphery markedly deteriorates with aging. These tendencies are true in conventional discrimination-reaction tasks. Surprisingly, however, we found that they are entirely different when reactions are induced by the same visual stimuli during reaching movements. The reaction time for a stimulus in the visual periphery was significantly faster than in the central vision, and age-related slowing of reactions to the stimulus in the visual periphery were quite small, compared to that observed in the conventional reaction tasks. This inconsistent slowing of reactions in different motor conditions underscores a distinctive visuomotor pathway for online control, which is more robust against age-related deterioration.