A new atom-based magnetic sensor could help scientists get a clearer look at how children’s brains work.
Magnetoencephalography, or MEG, is an imaging method that uses magnets to measure the magnetic fields created by electrical activity when different parts of the brain are activated. It is frequently used to map the areas of the brain associated with different cognitive functions, as well as identify specific signatures related to conditions such as autism and epilepsy.
Yet MEG is notoriously difficult to use with wriggly infants and young children; the scanners use bulky, helmet-shaped arrays of supercooled sensors called SQUIDs—superconducting quantum interference devices—and children often become frightened of the enclosed space or find it difficult to stay still. Only a few research centers in the country have the capacity to use MEG for children’s brain imaging, and only one, the Institute for Learning and Brain Sciences at the University of Washington in Seattle, has the capacity to study infants in this way. That has meant that much of what we know from brain research on cognition and sensory perception comes from studies of adults, whose mature brains may respond very differently from those of still-developing children and adolescents.
That’s why a new sugar-cube-sized sensor being tested by the National Institute of Standards and Technology in Boulder, Colo., has such promise.
The tiny senor, which successfully measured brain activity in a series of experiments in Berlin last week, uses an infrared laser and fiber optics to measure the light absorbed by 100 billion rubidium atoms contained in a gas. The rubidium absorbs light in proportion to a magnetic field, and can operate at room temperature.
That means such sensors could someday lead to light, flexible MEG helmets that would give children the ability to move around while wearing them, according to Svenja Knappe, a co-developer of the sensor and a physicist with the atomic devices and instruments group at the National Institute of Standards and Technology in Boulder, Colo.
“It will take several years to develop a prototype system that can be used for actual clinical studies, but we are excited about the first steps we made in this direction and the encouraging results that make us believe that our mini-magnetometers can become an alternative to SQUIDs in certain biomedical applications,” Knappe said.
The research team still has a ways to go to develop more sensitive measuring devices to use with the sensors. Yet if the mini-sensor matures, it could go a long way toward making brain research more relevant to education.
Photo: The mini-sensor’s tiny lens, visible in the sensor, allows a low-energy infrared beam to measure magnetic fields created by human brain activity. Photo courtesy of Svenja Knappe and NIST.