Does vibration-induced kinesthetic illusion accompany motor responses in agonistic and antagonistic muscles?

The technique of vibration-induced illusory movement has been used to study the mechanisms of perception and the brain network responsible for eliciting kinesthesia since it was first reported by Goodwin and colleagues in 1972. Vibration applied to the skin surface over the tendon of limb muscles excites primary afferent spindles, and subjects experience movement sensations as if the vibrated muscle were stretched, despite the limb being immobile. In addition, tendon vibration can induce tonic muscle activities in both the vibrated muscle and its antagonistic muscles. It was formerly believed that these motor responses accompanied the kinesthetic illusion of the vibrated limb. However, if subjects relax their limb completely and focus their attention on the movement sensed during vibration, a movement illusion can be elicited without any motor responses. This review focuses on the relationship between the elicitation of vibration-induced kinesthetic illusions and experimental conditions, and may provide insight into differences among studies of kinesthetic illusion.