Attenuated Input to the Primary Somatosensory Cortex is Associated with the Occurrence of Rubber Hand Illusion

The neural representation of the body is easily altered by the integration of multiple sensory signals in the brain. The “rubber hand illusion” (RHI) is one of the most popular experimental paradigms to investigate this phenomenon. During this illusion, ownership of the rubber hand is created. Some studies have shown that somatosensory processing in the brain is attenuated when RHI occurs. However, it is unknown where attenuation of somatosensory inputs occurs. Here, we show that somatosensory input from the hand is attenuated at the primary somatosensory cortex. We found that the early response of somatosensory evoked potential, which is thought to originate from the primary somatosensory cortex, was attenuated during RHI. Furthermore, this attenuation was observed before the occurrence of the illusion. Our results suggest that attenuation of somatosensory inputs from the hand to the brain is one of the factors influencing the occurrence of the RHI.