There is not a lot of literature about them, but from what i found their thalami are connected or fused together. Since thalamus is the crossroads for many sens

There is not a lot of literature about them, but from what i found their thalami are connected or fused together. Since thalamus is the crossroads for many sensory inputs the senses of one girl can pass on to further brain processing regions of both brains , e.g. their eye signals diverge and reach both girls' visual cortices. 1. Each brain controls more limbs than usual, but brains are plastic and can learn do that. It seems they have separate "personalities" however and they recognize themselves as different persons. So they don't "control" each other's consciousness although they seem to be able to communicate thoughts (not clear how) can control the limbs of the other, and can see what the other sees (e.g. with closed eyes, they can see what the other girl sees). Whats fascinating is how one of them can manage to override the movement signals coming from the other. Surely further examinations during their life will show how action initiation/inhibition happens in their brain. 3) It seems no, they dont control a limb simultaneously. They seem to be able to cancel the signals from the other person, presumably because their personal signals are much stronger (possibly because they have learned over time to do that ) or they have developed some mechanism to inhibit sensory signals from the opposite brain. This may be happening already at the level of thalamus where they are connected. Since their arms can possibly be controlled by both brains through the thalamic connection, i wonder if they can train themselves to use primarily the opposite person's limb, e.g. hand. It might be possible since the wiring is already there - it seems to only require sensorymotor traning. 2) I suppose you mean they have some kind of learning problems. But not really, people can learn and have normal IQ with much much less brain than what they may be allocating to the opposite body. And it's not even clear that they do that. They essentially share a thalamus but not much else , and even so, they dont seem to have less total thalamic mass than they would have separated . Also , thalamus being a relay rather than a decision taking region, it doesnt seem it would affect their intelligence too much. - http://ojs.library.ubc.ca/index.php/ubcujp/article/view/2521/182422 http://ojs.library.ubc.ca/index.php/ubcujp/article/view/2521...