There is still so much humans don't know about their own brains, and probably never will.
Professor Eccles said that "the brain is messenger to consciousness". Among other brain specialists he said the brain appears to process rather than produce consciousness.

Consciousness, the subjective experience of an inner self, could be a phenomenon forever beyond the reach of neuroscience. Even a detailed knowledge of the brain's workings and the neural correlates of consciousness may fail to explain how or why human beings have self-aware minds. - David Chalmers