A maelstrom of neural connections develop in a child’s brain during the first five years of life. Understanding how interconnected circuits develop, and how babies think, could lead to a host of new insights into everything from autism to language acquisition. But gathering such information has been tricky: infants can’t be ordered to stay motionless, which is required for most advanced neuroimaging techniques. Now a system that works in concert with existing imaging machinery can account for head movement and, for the first time, let researchers see detailed activity in an active baby’s brain.
Magnetoencephalography (MEG), a technology used to study brain function and to pinpoint diseased areas of the brain, capitalizes on the very weak magnetic fields created whenever a cluster of neurons fires at once. A helmet, resembling a salon hair dryer, with 306 sensors hovers over the subject’s head and detects where the magnetic pulses are occurring. Unlike magnetic resonance imaging (MRI) machines–which only show snapshots of data and require people to lie still inside a noisy, narrow tunnel while subjected to a powerful, rotating magnetic field–the MEG is pin-drop quiet and open, allowing subjects to interact with their surroundings. The resulting data can show researchers precisely where activity is occurring in the brain in real time.
Use of the technology in infants and young children has been limited because they typically need to be sedated to stay motionless long enough for traditional MEG machines to collect the necessary data. “The enemy for any kind of imaging, especially brain imaging, is movement,” says Sylvain Baillet, director of the MEG program at the Medical College of Wisconsin in Milwaukee. “It’s a bit like trying to take a picture of a child who’s constantly moving with a camera with a very slow aperture–the picture will be fuzzy.”
In order to study babies that were wide awake and socially engaged, researchers at the University of Washington’s Institute for Learning and Brain Studies (I-LABS) worked with Helsinki-based medical device company Elekta to create a “head-positioning” system remarkably similar to GPS. Scientists strap a soft nylon cap to the baby’s head. The cap has four embedded coils, each of which emits a high-frequency wavelength indicating its relative position at all times. As the hardware system tracks the skull’s movement, the software interprets the results and merges them with MEG-sensor data.
“For the first time, we can put babies and young children in this device while they’re engaged in a cognitive test,” says I-LABS codirector Patricia Kuhl. “Then, because you’re looking at the whole brain, you have the chance to look at interactions between various areas.” Some things stimulate neurons to fire in just a single region, while others trigger more complex neural responses across multiple locations of the brain–in children, this distinction is particularly important for understanding processes like language acquisition and potentially for diagnosing autism and other conditions.