Quantum effects in the brain: A review
arXiv Preprint Archive October 17, 2019 Betony Adams, Francesco Petruccione
This review examines theories proposing that quantum effects contribute to neural processing and consciousness. It describes how the initial microtubule hypothesis from the mid-1990s was dismissed because quantum effects seemed unlikely in warm, wet biological systems, but developments in quantum biology—showing quantum effects in photosynthesis, avian migration, and olfaction—have revived interest. The review covers proposals that general anaesthetics act through quantum means via electron spin changes, that the tunnelling hypothesis from olfaction applies to neurotransmitters, and that phosphorus nuclear entanglement might influence neuron firing. It assesses the experimental evidence supporting these theories and clarifies the proposed biological sites of quantum effects in the brain.