In January 2009, a documentary was filmed which reported on the twins, and followed their progress up to their third birthday. This documentary was released and aired in October, 2010. In this documentary, it was confirmed that though each girl has her own thalamus, there is a connector piece, a “thalamus bridge”, which connects the two thalami together. Through this shared brain tissue structure and the interconnected neurons, one brain receives signals from the other brain and vice versa. This documentary also reported on experiments that were carried out that confirmed that visual cortex signals based on what one girl saw, were received by both girls’ brains. So in effect, one twin could see what the other twin was seeing, making them unique even among craniopagus twins.
Extraordinary People Stories - Twin Life Sharing Mind and Body - YouTube
As craniopagus twins, 7 year old Tatiana and Krista are the only people in the world known to share a neural bridge between their thalamus - a part of the brain involved in the regulation of consciousness along with sensory and motor signals.