Erika Hayasaki writes: No one, it seemed, knew what the patient clutching the stuffed blue bunny was feeling. At 33, he looked like a bewildered boy, staring at the doctors who crowded into his room in Massachusetts General Hospital. Lumpy oyster-sized growths shrouded his face, the result of a genetic condition that causes benign tumors to develop on the skin, in the brain, and on organs, hindering the patient’s ability to walk, talk, and feel normally. He looked like he was grimacing in pain, but his mother explained that her son, Josh, did not have a clear threshold for pain or other sensations. If Josh felt any discomfort at all, he was nearly incapable of expressing it.
“Any numbness?” asked Joel Salinas, a soft-spoken doctor in the Harvard Neurology Residency Program, a red-tipped reflex hammer in his doctor’s coat pocket. “Like it feels funny?” Josh did not answer. Salinas pulled up a blanket, revealing Josh’s atrophied legs. He thumped Josh’s left leg with the reflex hammer. Again, Josh barely reacted. But Salinas felt something: The thump against Josh’s left knee registered on Salinas’s own left knee as a tingly tap. Not just a thought of what the thump might feel like, but a distinct physical sensation.
That’s because Salinas himself has a rare medical condition, one that stands in marked contrast to his patients’: While Josh appeared unresponsive even to his own sensations, Salinas is peculiarly attuned to the sensations of others. If he sees someone slapped across the cheek, Salinas feels a hint of the slap against his own cheek. A pinch on a stranger’s right arm might become a tickle on his own. “If a person is touched, I feel it, and then I recognize that it’s touch,” Salinas says.
The condition is called mirror-touch synesthesia, and it has aroused significant interest among neuroscientists in recent years because it appears to be an extreme form of a basic human trait. In all of us, mirror neurons in the premotor cortex and other areas of the brain activate when we watch someone else’s behaviors and actions. Our brains map the regions of the body where we see someone else caressed, jabbed, or whacked, and they mimic just a shade of that feeling on the same spots on our own bodies. For mirror-touch synesthetes like Salinas, that mental simulacrum is so strong that it crosses a threshold into near-tactile sensation, sometimes indistinguishable from one’s own. Neuroscientists regard the condition as a state of “heightened empathic ability.” [Continue reading…]