Illusory perception of arm movement induced by visuo-proprioceptive sensory stimulation and controlled by motor imagery

This paper investigates the illusory perception of movement induced through visuo-proprioceptive signals and the possibility of control the illusory movement itself through motor imagery. In particular we evaluated the cross-modal integration of the proprioceptive illusion, induced through vibro-mechanical stimuli, with visual feedback provided by means of a virtual avatar body. The visuo-proprioceptive signals were then integrated as an enhanced feedback for a motor imagery Brain Computer Interface, with the final aim of providing to the user both the perception and mental control of the illusory movement. For this purpose it was specifically developed a system capable of applying vibration stimuli in proximity of the biceps and triceps brachi muscle tendons, and so eliciting the illusory perception of a movement as the vibrated muscle is elongated. We report that the multimodal integration of the proprioceptive illusion with the visual feedback can be successfully induced, though it depends on the subjective perception of speed and onset time of the illusory movement. Moreover we show how it is possible to both perceive and control the avatar body by mental motor imagery through a brain-computer-interface.