The team is collaborating with experts at the Italian Institute of Technology, Harvard Medical School, and UC Irvine to gain a better understanding of the human brain.
“We are working toward fused human-technology systems that work synergistically to not only impact perceptions, decisions and actions of the soldier, but also to enhance the hybrid human system’s capabilities for rapid and adaptive decision making,” said Dr. Javier Garcia, an Army neuroscientist.
The researchers used transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging on volunteers as they executed a difficult attention tracking task.
“TMS is the type of neurostimulation that is simply an electromagnet that you put on your head and as you quickly send pulses through the electromagnetic, it induces current into whatever conductive body is next to it will, modifying neural activity – and sometimes behavior,” said Dr. Garcia. “We are stimulating the brain, except in this stimulation protocol, we use very rapid and consecutive pulses to the brain to inhibit a part of the brain.”
After a specific region of the brain was inhibited, the experts used a stroke model to examine neural changes and monitor the brain’s recovery. They wanted to track how long the changes would last, which brain networks would undergo changes from the stimulation, and the behavioral consequences.
“Noninvasive brain stimulation is a tool that allows neuroscientists to gain insight into disease spreading and compensatory reorganization following stroke,” said Professor Emily Grossman. “We know from patient and brain imaging work that brain injury to a focal, or localized, brain site has a spreading effect that destabilizes connected circuits far from the actual site of impact.”
Professor Grossman explained that in many cases the downstream effects are significant, but also difficult to predict due to the complicated nature of brain organization, which can be best described as a set of large-scale networks that have various points of connection.
“In this study, we target the attention network of the brain, which consists of a specialized set of brain regions involved in controlling where and when we best encode information about the world around us. Visual attention is essential for everything we do in daily life, including tasks like monitoring streams of visual information when driving, engaging in conversation and tracking our children on a busy soccer field.”
When individuals experience an injury to the attention network, tracking skills become impaired and it is more difficult to maintain focus on individual items embedded in a cluttered environment, said Professor Grossman.
“This study suggests that recovery may depend, in part, on the compensatory reorganization of brain networks downstream and connected to the site of impact. These downstream networks experienced a brief interval of dynamic reorganization after stimulation, and are known to be important for manipulating information that we are attending to and are using to make decisions about events in the visual environment.”
The experts in the U.S. Army Research Laboratory are investing in a variety of techniques and methods to further advance neuroimaging capabilities.
“This unique collaboration brings cognitive, clinical, and army researchers together from across the globe to probe the dynamic network changes as a consequence of neurostimulation,” said Dr. Garcia. “While we provided the innovative methods and analysis to this research – others brought the clinical and cognitive aspects.”
The international team plans to explore more neurostimulation protocols and apply this technology to a human-autonomy teaming perspective, building upon evidence that the brain can be prompted or manipulated to enhance decision-making and performance.
The study is published in the journal Scientific Reports.