Implicit online corrections of reaching movements.

Many neuroscience studies of arm control have attempted to explain how aimed movements are planned, generated, and corrected. The mechanisms of subconscious online reaching correction to a target shift are now being widely examined from computational, physiological, and pathological viewpoints. Recent evidence of a quick manual response to surrounding visual motion suggests an additional online compensatory mechanism in reaching movements for bodily and/or external environmental changes, although the computational principle underlying this process remains controversial. Together with preprogrammed voluntary motor command generation, it appears that multiple online visually guided correction mechanisms implicitly govern reaching control to bring the hand to the goal. It is important to reveal unknown mechanisms and underlying neural substrates of generating the response to visual motion, which is additionally modulated by action contexts.