Just because certain parts of the brain cause particular emotions, behaviors, stimulus, etc. doesn't mean that the person in general doesn't have a soul. A soul is simply something that you need to believe in, it isn't something that can necessarily be proven. It's like God I guess. As much as you can show these "facts" and undeniable "proof", fact of the matter is, all of that stuff was passed down over thousands of years, so who really knows what did and didn't happen?

Its all about the faith man, either you got it, or you don't.