This relates a lot to philosophy of mind and dualism vs physicalism. There are a lot of arguments for dualism (that you are immaterial and are not the same as your brain), for example, the indivisibility argument which goes:
1) Humans are all or nothing concepts: either you exist or you don't exist there's no such thing as 50% of a person.
2) However, on naturalism you are your brain so you are a dividable concept.
3) However people can lose parts of there brain, take the case of Phineas Gage and the French guy on infographics that had 10% of a brain due to problems.
Therefore there's an immaterial part to you, this can be backed further with intentionality, the "aboutness" or ofness about thoughts. When Ur leg hurts for example it's not the brain that's in pain! Even if it's involved in the process it's got a certain density, mass, volume and thoughts could be about vacations, you can have true thoughts, nothing about the brain states you have are true or false..Someone analysing your brain while Ur thinking will not be able to say "see that brain state right there, that's true!" Because thoughts can be true and false but brain states can't be. What this goes to reinforce is that there is a dualism interactionism between the brain and mind.
When the brain dies this immaterial part could continue to live, Paul describes this as a state of "nakedness" in the Bible, but eventually everyone in heaven gets a ressurection body.
Now I don't personally think I'm wrong however if I am wrong and there is no God then why couldn't people create an artificial heaven? If you are your brain, then couldn't you preserve the part of it that's "you", don't you think with all this technology we'd be working on an artificial afterlife project. Has anyone even ever proposed an idea like this before and if so why not.
Again the problem would seem to be due to the existence of the soul therefore you can't artificially store there intelligence in a computerised heaven, but if you're an atheist or a naturalist or both this seems like something that should be researched