Figure 1. General experimental set-up.

The subjects were exposed to a counterclockwise rotation of a textured tactile disk under their right hands (upper right) and/or a counterclockwise rotation of a visual scene projected via a video projector (bottom right) and/or a vibratory stimulation applied to the tendons of the pollicis longus muscle of their right wrists. The subjects held a potentiometer in their left hands to copy any illusory sensation perceived in their right hands. Potentiometric traces and EMG signals from the right extensor carpi ulnaris and pollicis longus muscles were recorded.