The 86 billion neurons of the human brain represent humankind’s primary evolutionary advantage and, perhaps, an area of untapped potential. Currently, our brains interact with the world through our bodies, sending electrical currents through the nervous system to vocalize with our mouths, to type—or swipe—with our fingers, or to move bipedally through space. Neurotechnological advances have already given quadriplegics the ability to perform basic operations in an F-35 simulator with their thoughts1 and have given scientists the ability to decode speech that subjects are imagining in their minds—albeit imperfectly. Eventually, our physical

Brain-computer interface (BCI) represents an emerging and potentially disruptive area of technology that, to date, has received minimal public discussion in the defense and national security policy communities. The U.S. Department of Defense (DoD) has invested in the development of technologies that allow the human brain to communicate directly with machines, including the development of implantable neural interfaces able to transfer data between the human brain and the digital world. This technology may eventually be used to monitor a soldier’s cognitive workload, control a drone swarm, or link with a prosthetic, among other examples. However, there is a sense of skepticism on numerous policy, safety, legal, and ethical fronts that need to be evaluated and answered before the technology can be assumed to its full potential.

Brain-computer interface (BCI) is a collaboration between a brain and a device that enables signals from the brain to direct external activity, the interface enables a direct communications pathway between the brain and the object to be controlled.

the Defense Advanced Research Projects Agency has suggested that “smart systems will significantly impact how our troops operate in the future, and now is the time to be thinking about what human-machine teaming will actually look like and how it might be accomplished. . .”

Work with BCI tends to fall into the following categories, which provide a framework for our investigations of operational relevance and applied capabilities in subsequent sections:

• data transfer from the brain
• direct system control
• prosthetics and paralysis treatment
• cortically coupled AI (for training or running AI systems)
• data transfer to the brain, and brain-to-brain communication.

these can be segmented further into work involving invasive systems and noninvasive systems. Invasive systems involve implanting electronic devices beneath the human skull, inside the brain. The surgery allows practitioners to place the implant exactly where desired to monitor precise sets of neurons that govern specific neurological functions, but it carries health risks. Alternatively, noninvasive systems sit outside the skull. While this reduces risk to the user, the skull essentially acts as a filter and muffles the electrical signal.