It is well known that visual information is necessary to execute accurate goal-directed tasks. Other sensory inputs as proprioception and vestibular information contribute as well, elaborating the initial state of the sensorimotor system during motor planning and keeping the on-line control of execution. The relative roles of vision and proprioceptive inputs, however, have still to be quantified. To this aim we investigate the influence of visual feedback on action planning by means of a visuo - motor conflict.
Visuo motor conflicts presented in the experiment: A) Horizontal arm motion (black arrow) with vertical visual feedback (white arrow) B) Vertical arm motion (black arrow) with vertical visual feedback in opposite direction (white arrow) C) Vertical arm motion with horizontal visual feedback (white arrow) .
We ask subjects to perform vertical and horizontal single-joint arm pointing movements, while they visually perceive either congruently or incongruently (e.g. orthogonally) directed movements. The changes in the arm velocity profiles produced by this visual feedback manipulation represent a good measure of the effect of a conflicting visual information on motion. This will allow us to check whether visual information can reorganize motor planning and change motion kinematics.