You put so much stock into the "old" brain. I find this curious, namely becuase your faith and belief in God seems important to you. Your pondering, your beliefs, your certainty that God exists, your soul searching to find your own faith, my decision to reject my faith, this all comes form our "new" brain.
How is it that you put so much more emphasis on the biological parts, and so little emphasis on what makes us human, essentially our "new" brain?