Quantum effects in the nerves and brain.

Abstract

Quantum biology is often referred to as an emerging field of research. In theory it shares its roots with the more general field of quantum physics. Many of the founding figures of quantum theory were intrigued as to whether its insights into the structure of matter might equally offer insights into living matter. Experimental evidence for quantum effects in biological systems took longer to emerge, with tunnelling in enzymes observed in the 1960s. More recently, advances in ultrafast experimental techniques have led to extensive investigation into the role of quantum coherence in energy and charge transfer in photosynthesis. Despite this long history, the role that quantum effects play in biological systems is still very much up for debate. Even more debatable is the role that quantum effects may play in that most complex biological system: the brain. Penrose and Hameroff, for example, have suggested that consciousness cannot be explained by classical processes, and their Orchestrated Objective Reduction theory has generated both interest and critique. Consciousness is the brain’s most profound secret and it remains to be seen whether quantum mechanics will prove a likely explanation. But, less ambitiously, the brain can also be described as a collection of nerve cells, whose function involves physiological processes similar to those in other cells. The aim of this thesis is to investigate how progress made in quantum biology might be applied to the specific context of neurology. To this end, the thesis revisits two of the models currently employed in quantum biological research. The first of these is the Posner molecule model of cognition, developed by Matthew Fisher. This hypothesis involves the entangled spins of phosphorus nuclei in calcium phosphate molecules, which have an influence on the balance of free calcium ions and thus neural activation. This original model is further developed here to investigate how entanglement and coherence are altered by the inclusion of lithium isotopes, and whether this might offer an explanation for the mode of action of lithium in treating bipolar disease. The second model investigated in this thesis is the vibration-assisted tunnelling model first developed in the context of olfaction. The hypothesis here is that olfactory receptors are potentially activated by an electron transfer that is facilitated by the vibrational modes of the olfactant. Ligand-receptor interactions are ubiquitous in biological systems and not least in the effective functioning of the nervous system. This thesis thus re-examines the vibration-assisted tunnelling model to determine how generalisable it might be, by taking the specific case of infection with the SARS-CoV-2 virus. While this virus-host interaction is not neurological, intriguing evidence that antidepressants can have antiviral effects as well as the profound effects that COVID-19 can have on the nervous system, suggests that this timely example might offer valuable neurological insights.