Quantum sensors for biophysical modelling of brain function

Brain disorders represent the biggest challenge for 21st century healthcare. 14.7M people in the UK live with a neurological condition whilst around 10M Canadians have a neurological or psychiatric disorder. These problems come at a significant cost: brain disorders cost the UK ~£100 billion per year; mental health issues alone cost Canada ~$50 billion per year. A barrier to effective management of brain disorders is the lack of technologies to objectively assess brain health. Whilst techniques like MRI have revolutionised diagnosis of disorders relating to structural abnormalities (e.g. tumours), for many conditions the underlying pathology relates to function - meaning either a change in brain chemistry (i.e. the chemicals that control electrical activity in cells) or the electrical activity itself. These are harder to measure and much of what we understand comes from research involving animals. Whilst it is possible to measure brain electrophysiology in humans (and to use these methods to infer underlying neurochemistry), the gold-standard is to place electrodes in the brain, which is highly invasive. Non-invasive techniques exist, which rely on measuring either electrical signals from the scalp surface (EEG) or magnetic fields generated by neural currents (MEG). EEG is limited in spatial resolution and sensitivity, particularly to ‘high-frequency’ signals which are markers of healthy brain function. MEG is more robust and has good spatial precision, yet classic MEG instrumentation lacks sensitivity and practicality, with scanners being costly and not well suited to many patient groups, particularly infants. Quantum sensors promise game-changing advancements in the assessment of human brain function. Quantum enabled magnetic field sensors – called OPMs – can lift the restrictions surrounding MEG recordings and recent simulations suggest that an appropriately constructed OPM-MEG device could even rival invasive measures of brain function in terms of sensitivity. This dramatic increase in sensitivity also comes at a low cost. In addition, OPM-MEG devices are much more practical, adapting to scan anyone (even babies) and enabling free movement whilst scanning. This could prove disruptive in the quest for cheap, accurate and non-invasive assessment of brain health. Here, our vision is to develop a quantum sensor-based imaging system for biophysical modelling of brain data. Specifically, our system will enable measurements of brain electrophysiology with a precision and sensitivity that has never previously been possible using non-invasive imaging. This, in turn, will permit mathematical models of brain circuits to be fitted to the data, elucidating the neuro-chemical pathways that underly the electrical function. Enabling this key advance will allow us to track how our brains change, for example over time, or following treatment. In our programme we will build the first quantum enabled scanner tailored to biophysical modelling and develop algorithms to exploit this increased sensitivity. We will test our new system in two ways: First, we will undertake a neuropharmacological study – exploring how brain chemistry and electrophysiology change with alcohol administration. Second, we will measure how brain networks alter with maturation, across the intense developmental period of adolescence. These studies will prove the principle, and the value, of biophysical modelling. Moreover, they will exploit the unique capabilities of quantum sensors for monitoring brain health. Ultimately, this will be transformative in human neuroscience and the technology we develop will find use in drug development, improving success rates in clinical trials, and moving the needle on precision medicine.