Conjoined twins Tatiana and Krista has unique abilities to see through the other's eyes. Recent functional MRIs demonstrate that physical sensation can be a shared experience too: one can feel the touch of a hand on the other’s kneecap, identify a particular toe being tugged, laugh when her twin is being tickled. They also may share some motor function.
They are conjoined not just by flesh and bone. Their brains are zippered together by a neural bridge between the thalami, the sensory processing hubs of their brains. This bridge, which the girls can flitter across at will, has raised questions and inspired a sense of wonder among even the most seasoned specialists.
How does it work? What are its limits? What could it mean to our understanding of the ability of the brain to change and adapt? What does it mean in terms of how we understand the development of personality, empathy and consciousness?
Doug Cochrane, a neurosurgeon at B.C. Children’s Hospital, was part of a multi-disciplinary team assembled to attend the birth and followup care of the girls in 2006. He had never worked with a set of craniopagus twins; conjoined twins are extremely rare and those joined at the head are the rarest, with an occurrence rate estimated at one in 2.5 million births. Few survive.
Via Dr. Stefan Gruenwald, Kimmy S