The Quantum Brain
Prof Michael Crawford at Nutritious Minds launch
Professor Michael Crawford

An introduction to a theory on the role of π-electrons of docosahexaenoic acid in brain function” – The 2015 Chevreul Medal lecture, Lipids and Brain III Conference

By M.A. Crawford  M. Thabet and Y. Wang

Published June 2018

If what we conclude in this paper is correct – and I believe it is – it is a game changer, as it establishes the reason why DHA is of such critical importance for the brain.


In Part I, we discuss the background to views on brain function and our thesis that it is conducted by π-electrons which perform sensory reception, memory, action, cognition and consciousness. Our thesis is consistent with the classical views of ion movement and synaptic protein strengthening. However, protein based views contain no element of precision for the signal. Precision is essential for true signal transduction of sensory input and the faithful execution of learnt neural pathways.

In Part II, we incorporate these principles to discuss the mechanism whereby electron function adds precision of signal energy to the process through the Pauli Exclusion Principle. The Huxley-Hodgkin (HH) account of neural function describes the movement of sodium, potassium and calcium ions to create electrochemical potentials across membranes with well-established mathematical and experimental support.

To explain learning, consciousness and perception, others have claimed brain function depends on protein synthesis or RNA coding. Some consider super position and collapse as the computational mechanism. This however is fragile with no mechanism described to protect from natural collapse and decoherence at the temperatures of the brain.

A novel approach was adopted by Penrose and Hammeroff who describe consciousness as a function of ʻobjective reduction’ (ʻOR’) of the quantum state. This orchestrated OR activity (ʻOrch OR’) is taken to result in moments of conscious awareness and/or choice (Hameroff S, Penrose R. 2014 Consciousness in the universe: a review of the ʻOrch OR’ theory. Phys Life Rev11(1): 39–78. Doi: 10.1016/j.plrev.2013.08.002. Epub 2013 Aug 20). Orch-OR operates in principle in protein tubules of neurons.

This concept is non-computational and has received much attention with a convincing advocacy and its share of criticism. The advocacy includes the fossil record of organisms that emerged throughout the first Cambrian period with onset roughly 540 million years ago (mya). They had essential degrees of microtubular arrays in skeletal size, complexity and capability for quantum isolation.

Attractive as this hypothesis may be, we point out that the brain is predominantly made of lipid, not protein. We suggest that both protein and RNA in the brain would more likely have been required to serve the extraordinary energy requirements for the brain. Early photosynthetic systems such as the dinoflagellates are rich in docosahexaenoic acid (DHA) including di-DHA phosphoglycerides as also in contemporary mammalian photoreceptors.

We wish to discuss in Part II, quantum mechanical properties of the π-electrons of DHA suggestive of a mechanism for the depolarization of the receptor membrane at a precise energy levels as required for vision and neural signalling (Crawford MA, Broadhurst CL, Guest M et al., 2013. A quantum theory for the irreplaceable role of docosahexaenoic acid in neural cell signalling throughout evolution. Prostaglandins Leukot Essent Fatty Acids (PLEFA) 88(1): 5–13. Doi: 10.1016/j.plefa.2012.08.005. PMID: 23206328). We wish to extend this principle to a concept of brain function in learning, recall, perception and cognition.