A lot of knowledge about what different bits of the brain do has come from people who have survived devastating brain injuries. (I remember that guy with the iron rod through his head from psychology 101.)
Well, my student managed to damage the 'pronoun' bit of his brain. He lost them in both English and Chinese (his mother tongue). So, that might prove something about the innateness of certain grammatical functions and the possibilty of the actual existance of a 'universal grammar'.

(Then again, it might not.)