Induction of illusory limb movement as a means of studying sensorimotor interactions in the eye-arm system

In the present study, illusory movements were used as a means of investigating certain sensorimotor interactions: it was proposed to describe the effects produced on the oculomotor system when muscular proprioceptive afferents in the arm were artificially activated by tendon vibration. The gaze displacements induced by these vibratory stimuli were analyzed in terms of the instructions to subjects (i.e., 'simple fixation', allowing the possibility of ocular tracking, or 'obligatory fixation', not allowing any eye movements) and the points in space on which the subject's gaze was required to be fixed (on the hand or elsewhere). The results show that, whatever the experimental conditions applied, the oculomotor system always reacted to vibratory stimulation of proprioceptive afferents, even though no corresponding visual stimulus was present.