Independent Online Visuomotor Control to Cursor and Target Motion

Skilled control of visually-guided reaching is fundamental for many daily activities. Visual information about hand and target position are used for movement planning and online corrections through rapid visuomotor feedback responses. Such feedback control is generally believed to implicate a single error signal, representing a difference vector between hand and target position. Here, we directly assess whether shared or independent systems serve visually-guided feedback control. We tested whether feedback gains can be independently modulated by hand/cursor and target motion through manipulating the task-relevance of each signal during goal-directed reaching. Our results demonstrate that the gains of visuomotor feedback responses to perturbed hand and target motion can be set independently of one another, at the same time, as a function of task-relevance. By dissociating feedback control of cursor and target signals, our findings support the existence of two independent visuomotor feedback pathways, revealing a more flexible neural architecture for goal-directed action.