Reply to your edit:
I know it would be ideal if there was a simple, short answer, but this question is nearly the equivalent of "please explain all the core ideas of neuroscience/neurology/neuropsychology to me". It's a good question, but it's a big question. This is why in the other thread [1] I've tried to point you in the direction where you will find the answers you are looking for: the answers exist and are for the most part known, but you have a lot of reading ahead of you, and there's no way around that.