Magnetoencephalography goes on the move

Roberto Saracco August 2, 2018 Blog 1,205 Views

A current stationary MEG scanner on the left, a bulky contraption. On the right the new wearable scanner allows patients to move around. Credit: National Institute of Mental Health and University of Nottingham

In the quest to unravel the working of the brain scientists are using several kind of “sensors” to see how the brain works.

Magnetoencephalography, an approach developed in the last century (1968), allows medical doctors and researchers to watch the brain electrical activity by sensing the magnetic field generated by the neuronal activity. Over the years more and more sensitive methods to capture these tiny magnetic fields have been found, like SQUID -Superconducting Quantum Interference devices. One of the problem with MEG is that the signals to be measured is some 10,000 to 1,000,000 times weaker (depending if we are looking at cortical activity or the alpha activity) than the ambient noise. Hence the challenge of keeping at bay the ambient noise.

This leads to the use of very bulky contraptions, see the image on the left, where there may be some 300 sensors shielded by the environment through a huge helmet.
Another problem with MEG is that the signals detected are greatly influenced by movement of the patient, like the blinking of eyelids or muscular contraction so the patient is asked to relax and be as still as possible.

Now researchers at the University of Nottingham have looked at this “negative” influence from an opposite view. Since any movement influences the MEG it means that the signals detected are showing the brain activity resulting from movement, hence looking at those signals would provide information on the brain workings when the body is engaged in specific activities, shedding light on its processing.

The problem, of course, is that you cannot really move when your head in constrained inside an helmet attached to a contraption weighting some 500kg!

Here is where the work of the researchers at Nottingham Universities shines: they have managed to develop a “wearable” MEG that allows the patient to move around and even play table tennis.

The hope is to harvest more and more information on what is going on in the brain and reverse engineer those data to understand how the brain works.