It's clear from some of your comments, that this is a subject people are thinking about. How about this: The mind is something that does not age. Those little old ladies you see walking with their walkers - are thinking the same way you are. At least, they are thinking the same way they always thought. The mind does not have a "little old lady" version of itself. It was the same as a child, as it is as a retiree. I don't know about you, but that came as a shock to me. As a young woman, I viewed aging as something that happened to every part of self. It is true of the brain, and all other bodily parts. But the mind stays the same.
Think about it. Do you "think" any different now then you did ten years ago? (I know you are probably wiser, and more mature, but I'm talking about the "voice" in your head - is it ten years older?)
So if the mind is an interaction of the brain and the spirit - is it our soul?