Brain imaging studies in humans have revealed the existence of a visuo-tactile system, which matches observed touch with felttouch. In this system, the primary somatosensory cortex (SI) appears to play a causal role in the visual processing of tactile events.Whether this visuo-tactile mechanism for touch in SI applies to the sight of ‘any’ touch, or whether it is restricted to the domain ofbody-related tactile experiences remains unresolved. To address this issue, repetitive transcranial magnetic stimulation (rTMS) wasused to determine whether activity in SI is strictly related to the visual processing of human body-part interactions, or is also involvedin processing the contact between inanimate objects, or between human body-parts and objects. The results show that rTMS over SIselectively impaired the processing of a contralateral visual stimulus depicting a human body-part being touched by a human agent,while it did not affect the visual perception of contact between objects, or between human body-parts and objects. Correlationanalysis shows that this effect was associated with the intensity and embodiment of the observed touched. This result suggests thatSI is more suited to represent social touch, contributing to our understanding of the effect of interpersonal tactile interactions betweenpeople.
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