Even if we're talking about visual and auditory hallucinations in a person who is shut off from all light and sound stimulation, say in a sensory deprivation tank, I'm still certain the experience is a result of the normal visual and auditory neural systems functioning abnormally for whatever reason. There is not some "not normally used" separate brain area dedicated to hallucinations. But if you find any research that makes a different claim, and it's from a credible source, please do share.
My education is in physics, but I read this book called "The Minds of Men and Machines" that explained the architecture of the brain in terms of a computer. It basically said there's three types of brain function (input, computation, output). Equivalently (sensory, cognitive, muscles) I think.
Anyway, in these terms (If I have the theory right here) is hallucination a malfunction in sensory (input) or cognitive (computation) or both? Or do different types occur in different functions?
You may have answered this, but I don't understand a lot of the biological terms.