Reality is. Consciousness is.. questionable. I have one. You? I don't know, I'm experiencing reality and you seem to have one, but I can never know it.

Computations on the other hand describe reality. And unless human brains somehow escape the physical reality, this description about the latter should surely apply here as well. There are no stronger computational models than a Turing machine, ergo whatever the human brain does (regardless of implementation) should be describable by one.