Abstract
Galvanic Vestibular Stimulation(GVS) affects a sense of equilibrium and produces vestibulo-ocular reflex(VOR). The VOR produces torsional impressions and eye movements. However, which does electrical current pathway produces VOR? How does GVS effects to VOR? These questions are unclear. As the cause of these, the vestibular system is formed by semicircular canals and otolith organs, and it has not been determined which of these two organs the GVS affects. In this report, we hypothesize that the electrical current through the otolith organ is an effective factor for eye torsion, and propose the electrical current path model as a resistance network. The model assumes three paths: horizontal left-right, horizontal front-back, and vertical, since electrical current in low frequency band pass only through foramen in the cranium. In this electrical current path model, the differential electrical current vertically penetrating the left and right otolith organs is an effective factor for eye torsion, and the phase of eye torsion changes depend on the direction of the electrical current. To verify the validity of this model, the amount of electrical current following each pathway is suppressed by adding percutaneous short-circuits to the otolith organs, and the mechanism of each electrical current pathway and its contribution to the amount of visual torsion is clarified, under 0.1~1Hz GVS condition. The results show that the transcranially connected short circuit changed the subjective report and behavior of eye torsion. These results support the hypothesis of our proposal. The electrical current path model is expected to improve the controllability of eye movements by GVS.