"Note that we have two diametrically opposite points of view here: Penrose takes a more conservative position, saying that an individual microtubule undergoes some conformational change which decoheres a superposed state. Stapp takes a much more radical view, saying that the entire brain performs a quantum measurement and somehow adopts its overall configuration in response to a single quantum measurement. The question is, is such a thing possible, and how could this produce consciousness?"
Not diametrically opposed so far as I can see. Stapp reaches for the totalized state of consciousness as that which undergoes a shift with q collapse or decoherence; Penrose and Hameroff contemplate it as involving less than the whole brain. No one knows at present which is more likely to be accurate.