Researchers intend to capture the complexity of brain signaling during face-to-face interactions
Credit: Clayton Metz/Virginia Tech
As you read, your brain’s cells are generating electrical currents that emit infinitesimally small magnetic fields. Now, Virginia Tech scientists can measure them using a new brain imaging technique called optically pumped magnetometry.
Researchers at the Fralin Biomedical Research Institute at VTC have received a $2.4 million grant from the National Institute of Biomedical Imaging and Bioengineering, part of the National Institutes of Health, to measure the brain’s subtle magnetic signals in two research volunteers simultaneously as they interact, capturing the rich complexity of the brain’s signaling during face-to-face social interactions in real-time.
Optically pumped magnetometry devices are wearable, lightweight headsets that measure brain activity while research volunteers can move around, interact with others, and sit upright. The device, which looks like a hat with wires connected to it, uses quantum sensor chips to measure the strength and originating location of magnetic fields produced by the human brain.
Unlike noisy, cramped MRIs, which require participants to lie down and stay still, the new headset allows for movement. This opens up new doors to study babies and children while they’re awake and in motion, as well as research volunteers who have movement disorders.
“We’re giddy to get people outside of magnets and into a setting where we can study social interactions, humans of all ages and sizes, and people in motion with fewer environmental limitations,” said Read Montague, principal investigator on the grant, professor with the Fralin Biomedical Research Institute and Virginia Tech College of Science’s Department of Physics, and director of the institute’s Center for Human Neuroscience Research. “We’ve never had the ability to make such sensitive direct magnetic measurements, and now we’re applying this transformative technology in the social domain.”
Over the past three years, Montague and his team have established one of the nation’s first optically pumped magnetometry laboratories in Roanoke, Virginia, at the Fralin Biomedical Research Institute.
Co-principal investigator Stephen LaConte, associate professor and an expert in advanced neuroimaging at the Fralin Biomedical Research Institute, said they aim to use optically pumped magnetometry sensors to conduct movement-tolerant brain imaging simultaneously with two research volunteers.
“It is difficult to overstate the importance of face-to-face interactions for human neuroscience. Face perception is one of the most critical functions in social interactions and is one of the most vital human perceptual skills,” said LaConte, who is also an associate professor of biomechanical engineering and mechanics in the College of Engineering.
Montague has been interested in optically pumped magnetometry for over a decade. In 2010, the researchers at the National Institute for Standards and Technology who developed the technology published the first study describing the use of miniaturized atomic magnetometers to measure biological activity in the brain and heart.
The technology was further refined by a company that engineers the sensors, QuSpin, led by Vishal Shah, a consultant for the new grant. Montague’s collaborators at the University of Nottingham in the U.K. were among the first to evaluate the new technology. They published a pivotal proof-of-concept Nature paper in 2018.
Building on that research, Montague, LaConte, and their collaborators at the University of Nottingham will be the first to use optically pumped magnetometry to observe two brains simultaneously.
Optically pumped magnetometers are incredibly sensitive — picking up subtle magnetic fields on the quantum scale of femtoteslas, about a billion times smaller than the Earth’s magnetic field. The optically pumped magnetometry sensors work by passing a laser beam through a glass cell filled with vapor. Magnetic fields generated by the brain shift the vapor’s atomic energy levels in the cell, either enhancing or fading the light current.
The cell’s sensor detects changes in the laser beam and produces an electric current proportional to the amount of light passing through it, converting a magnetic signal into an electric one.
The scientists use computational modeling to visualize which brain regions are most active during certain tasks, such as tapping a finger or playing a game with another participant.
But for the sensors to work, the researchers need to eliminate interfering signals that muddy the data. Nearby automobile traffic, a piece of misplaced metal, and even the Earth’s core all produce interfering magnetic signals. That’s why the new laboratory is set inside a magnetically shielded room made of mu-metal, a nickel-iron alloy. The researchers use additional coils to further shield remnant signals and help refine the data.
Montague expects the Human Magnetometry Laboratory to become a shared resource for neuroscientists at the Fralin Biomedical Research Institute.
“Here we have faculty with unique research strengths for the study of decision-making, social interactions, addiction, mother-baby interactions, and neuromotor rehabilitation. Our investment in human magnetometry positions Virginia Tech to unlock previously unrealized potential for gaining new insights into healthy brain function and a range of brain disorders that impact children and adults,” said Michael Friedlander, executive director of the Fralin Biomedical Research Institute and Virginia Tech’s vice president for health sciences and technology.
“Read Montague has always been at the very leading edge of brain research innovation. This exciting new approach taken by his team and the other groups at the research institute links technological innovation to solving problems of profound consequence for science and medicine,” Friedlander said.