  We criticize the Hameroff Penrose model in the context of quantum brain model
by gravitational collapse orchestrated objective reduction, orch. OR, assumed
by Penrose, and we propose instead that the decoherence process is caused by
interaction with the environment. We consider it useful to exploit this
possibility because of the growing importance of decoherence theory in quantum
measurement, and also because quantum mechanics can be applied to brain study
independently of the Hameroff Penrose model for mind and consciousness. Our
conclusion is that the Hameroff Penrose model is not compatible with
decoherence, but nevertheless quantum brain can still be considered if we
replace gravitational collapse orch .OR with decoherence.

Quantum Physics