You only point to your head due to modern science; Aristotle thought the brain was for cooling the blood as the ancient Greeks thought the soul was in the liver, hence Prometheus' punishment (although ψυχή was literally "breath" -- cf "atman"). Plenty of cultures thought it in the heart, as do we talk of the heart or gut or generative organs making decisions -- certainly we feel the tough decisions there.
Could it be those with extensive amputations of gut and an articial heart could be "less human" in a broader sense than just mass?
But you seem awfully sure there is consciousness. Perhaps there is no such thing and you only think there is? It seems like a handy mechanism for your genes to use to propagate themselves.
The homunculus model, while popular, isn't particularly insightful and is, recursively, useless.