Abstract
In the rubber hand illusion, people feel the tactile sensation from the stimulation of a rubber hand placed in front of them, instead of from own hand, which is also stimulated but hidden under a table. This illusion suggests that the visual sense can control tactile sensation. However, it is unclear how we resolve the inconsistency between the visual and somatic senses when the two senses are mismatched. Here we show that, using a visual stimulus alone, participants felt as if the palm and the back of fifth finger of own hand was touched simultaneously when the palm of own hand and the back of rubber hand were facing upward while they observed that the back of first finger of rubber hand was stimulated. In our rubber hand illusion, we found that two tactile sensations can be induced by one visual stimulus. When the visual and somatic senses are mismatched, only the visual sense regarding the spatial location and the somatic sense regarding the direction of the hand are integrated. This illusion suggests that somatic senses contribute to tactile sensation as well as visual senses, and that the visuo-somatic integration is modulated in part by a neural mechanism with low spatial resolution in multi-sensory area.
This work was supported by the “Open Research Centre” Project for Private Universities: Matching fund subsidy from MEXT (Ministry of Education, Culture, Sports, Science and Technology), 2005–2009.