Relationship between kinesthetic illusion induced by vibration stimulation and muscle discharge activity and changes induced by touching

Abstract

We investigated the relationship between muscle discharge and kinesthetic illusion caused by vibration stimulation of tendons and the effects of touching. To 12 healthy adult subjects under blinded condition, vibration stimulation was given at the distal portion of an extensor muscle of the right forearm；and the kinesthetic illusion expressed as changes in the left wrist joint angle and the electromyograms of the flexor and extensor muscles of the right forearm were recorded. We also investigated the correlation with their emotion and interoception characteristics when touching was performed with the application of vibration stimulation. Kinesthetic illusion triggered by vibration stimulation was observed at the wrist joint. Muscle discharges from the flexor and extensor muscles of the forearm increased, but a positive correlation with kinetic illusion was observed only for the flexor muscles. Touching caused the kinetic illusion to disappear；but it increased muscle discharges from flexor muscles, showing a correlation with interoception characteristics. Muscle discharge activity in the flexor muscles may be involved in the perceptual to motor transformation of proprioceptive information via the cerebral cortex. Psychosomatic correlation through sensory-motor integration at the cerebral cortex level was clarified from the degree of kinesthetic illusion caused by vibration stimulation, its correlation with muscle discharge, and the effects of touching on the phenomena.