Interpersonal gargalesthesia.

When someone touches, say, your upper arm, mirror neurons in your brain's area S2 fire. These neurons also fire when you merely watch another person being touched. However, you do not literally feel the touch from his arm on your own skin. Consistent with this view, we find when someone's arm is removed, he does start experiencing another's sensations [Ramachandran, V. S., & Brang, D. (2009)]. A congenital variant of this syndrome also exists, as in our subject TC. TC experienced referred touch, referred tickle in her axilla, and was able to tickle herself.