The new technique starts with magnetoencephalography (MEG), which works by measuring the magnetic fields produced by electrical currents in the brain as neurons fire. Normally MEG requires big bulky machinery, or at least cumbersome helmets, but the team found that pairing it with new quantum sensors enabled much more compact equipment, and made the process simpler and more precise.
The quantum sensors are known as optically pumped magnetometers (OPMs), and they’re able to sit closer to a patient’s skull than other sensors. That lets them make more accurate measurements in both time and space – meaning they can measure changes that take place very quickly, and better pinpoint where signals originate within the brain.
“It’s the quantum technology which makes these sensors so accurate,” says Professor Peter Kruger, an author of the study. “The sensors contain a gas of rubidium atoms. Beams of laser light are shone at the atoms, and when the atoms experience changes in a magnetic field, they emit light differently. Fluctuations in the emitted light reveal changes in the magnetic activity in the brain. The quantum sensors are accurate within milliseconds, and within several millimeters.”
The team tested the sensors on three patients as they underwent standard brain scans while watching visual stimuli. They found that they could measure how fast signals were moving across the brain, with a lag down to just 10 milliseconds.
This could make the quantum sensors potentially useful as a diagnostic tool for a range of neurodegenerative diseases. Patients could, for example, undergo a scan to measure the speed of their brain activity, and have follow-ups a few months later to see if that speed is decreasing over time. If so, it could be an early indicator of certain diseases.
“It’s our hope with this development that in discovering this enhanced function of quantum brain scanners the door is opened to further developments that could bring about a quantum revolution in neuroscience,” says Aikaterini Gialopsou, lead author of the study. “This matters because, although the scanners are in their infancy, it has implications for future developments that could lead to crucial early diagnosis of brain diseases, such as ALS, MS and even Alzheimer’s.”
The research was published in the journal Scientific Reports.