DARPA to Use Electrical Stimulation to Enhance Military Training

U.S. Department of Defense backs peripheral nerve stimulation as a tool to improve learning and military skills

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Emily Waltz is the power and energy editor at IEEE Spectrum.

US Department of Defense announces program to fund research that aims to improve learning peripheral nerve stimulation
Illustration: Science Photo Library/Getty Images

It takes years to learn some of the most important national security skills, such as speaking foreign languages, analyzing surveillance images, and marksmanship. The U.S. Department of Defense (DoD) wants to speed up that training process using electrical stimulation to enhance the brain’s ability to learn. The Defense Department’s research arm, the Defense Advanced Research Projects Agency (DARPA), today announced it had awarded multimillion-dollar contracts to eight university groups that will study and develop such technologies. 

DARPA wants to see a 30 percent improvement in learning rates by the end of the four-year program. Studies will be conducted on human volunteers and animals. DARPA did not disclose the total value of the research contracts. 

This isn’t DARPA’s first foray into electrical and other kinds of nerve stimulation. In 2014, it sponsored direct brain stimulation research in a project called RAM that aims to restore memory in people with traumatic brain injuries. Scientists last week published the first major results of that program. And in 2015, the agency bet on electrical stimulation as a therapeutic technique for treating disease, awarding contracts through its ElectRx project.  

For the new stimulation project, dubbed targeted neuroplasticity training, or TNT, research teams will focus on peripheral nerves that project into the brain and tug at memories. By delivering electrical pulses into the body’s nervous system, the scientists aim to modulate the brain’s neural connectivity and production of key chemicals. That kind of neural tuning can “influence cognitive state—how awake you are, or how much attention you’re paying to something you’re viewing or performing,” says Doug Weber, a bioengineer at DARPA who heads up the TNT project.

If it works—if researchers can improve a person’s ability to learn—the DoD could reduce the amount of time spent training soldiers and intelligence agents. “Foreign language training is one of our primary application areas because it’s very time intensive,” says Weber. Language courses last more than a year, and only about 10 percent of trainees reach the level of proficiency needed for their jobs, he says. 

Weber says he envisions intelligence agents or soldiers wearing some kind of noninvasive stimulation device that delivers precise electrical pulses as they practice their skills. And unlike caffeine or energy drinks, the stimulation can be turned off and, hopefully, causes fewer side effects.

But before DARPA can sharpen its sharpshooters, it must figure out exactly where and how to stimulate the body’s nervous system. That’s the charge to the university groups—to understand the anatomy and function of neural circuits associated with learning. 

The brain may seem like the obvious place to start, but DARPA has asked researchers to focus instead on the peripheral nervous system—nerves outside the brain and spinal cord. Peripheral nerve circuits are simpler and easier to map than those of the brain. And they tend to be more accessible than those in the brain, making surgical implantation of electrodes less invasive. “It would be impossible to justify a brain implant for someone who is otherwise healthy,” says Weber.

The teams awarded the research contracts will start with the vagus and trigeminal nerves. A team headed up by Stephen Helms Tillery, a neuroscientist at Arizona State University, for example, will study the anatomy and role of the trigeminal nerve—a cranial nerve responsible for sensations and motor function in the face.

Evidence suggests that this nerve complex has access to areas of the brain stem that release norepinephrine, a chemical associated with attention, and dopamine, a chemical linked to the brain’s ability to adapt. Helms Tillery’s team will study the anatomy and function of the trigeminal nerve in rhesus macaques.

Tillery’s team will also stimulate the trigeminal nerve in human volunteers to see how it affects behavior. In one experiment, with help from the U.S. Air Force Research Laboratory, volunteers will watch surveillance video and try to identify a person carrying a weapon. In another experiment, in partnership with a military research laboratory called USARIEM, volunteers will fire rifles at long ranges in a virtual shooting range while their behavior and performance are quantified. 

Other TNT awardees are focusing on the vagus nerve—a major neural throughway that connects most of the body’s key organs. Researchers in 2011 reported in Nature that stimulating the vagus nerve enabled rats to better recognize auditory cues. That report, in part, inspired DARPA’s TNT program, Weber says.  

TNT researchers will likely face some ethical questions, such as the ethics of using enhancement on war fighters, says Helms Tillery. And if electrical stimulation proves effective at enhancing learning, how pervasive and mandatory it would become in the military is unclear.  

Weber says he envisions electrical stimulation being a choice—one that enlisted soldiers will want. “There are elite performers who are eager for anything and everything that would give them an additional boost or benefit. For these individuals, I think it would be fantastic if we can help,” he says. But “it’s likely that the initial users won’t be enlisted folks. They’ll be civilians working for the DoD. They have a bit more autonomy than some enlisted folks,” he says.

DARPA is funding an ethics workshop to be hosted by Arizona State University within the first year of the TNT program. 

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