Neuroscience, Deployed: An Intellectual Arms Race

by Tressel Holton

art by Vivian Yang

“The arms race is a race between nuclear weapons and ourselves.”

- Martin Amis, in his 1987 book Einstein’s Monsters

The history of warfare has been accompanied by several arms races, by which nations or other militarized groups challenge each other to develop the most devastating weaponry possible. Arms races drive innovation, epitomizing the relationship between war and the scientific community. Perhaps the most infamous example is the race for nuclear power that arose during the Second World War and continued throughout the U.S.-Soviet Union Cold War. Before the end of 1945, the nuclear arms race claimed between 110,000 and 200,000 lives in Hiroshima and Nagasaki [1]. Yet within the broader history of global war lies a quieter scientific struggle, an entirely different kind of arms race driven by humanity’s growing ambition to understand and influence the brain.

For as long as medics have found themselves on the battlefield, physicians have been concerned with treating injured soldiers. As early as the year 1600 BCE, Ancient Egyptian surgeons began to visualize the connections between the mind and the nervous system by observing neurological symptoms in tandem with traumatic brain injury [2]. However, it wasn’t until the 1860s that the American Civil War brought about the official dawn of neurology, the branch of medicine that specializes in treating the brain and nervous system. By the 20th century, war stopped merely shaping neuroscience as neuroscience began to reshape war. Thus, a scientific arms race began: the nations of the world as its sprinters, neuroscience as the track, and warfare as the finish line.

The Dawn of Neurology During the Civil War, budding medics relied on the teachings of Thomas Willis, a 17th-century English anatomist and physician who published the foundational neuroanatomy textbook Cerebri anatome [3]. The research conducted by Willis introduced an empirical approach to medicine, encouraging doctors to support treatment decisions with scientific evidence rather than popular assumptions like the reliance of health on “humours,” bodily fluids that were believed to control one’s emotional state [4]. 

Willis’s fundamental principle guided the decision-making of Civil War-era physicians like Silas Weir Mitchell and George Morehouse. Mitchell and Morehouse established the first neurological clinical ward in Philadelphia in 1862 in response to a steadily increasing number of soldiers who were left with neurological disorders and injuries [5]. These neurological pioneers were left baffled—what made these gunshot wounds to the head different from those previously seen? More critically, what could we learn about the brain from these patients? The answer to these questions lies in the relationship between anatomy and brain function.

Historian Earl J. Hess addresses the first of these questions by explaining that the American Civil War introduced the single-shot, muzzle-loading rifled musket, which rendered its predecessor, the smoothbore musket, entirely obsolete [6]. The improved range and accuracy of the single-shot musket led to a significant increase in gunshot wounds and, to neurologists’ benefit, an increase in survivors of gunshot wounds. In other words, this technological development gave neurologists a small cohort of patients who had miraculously survived precise shots to the head, reinforcing the idea that a person could live even with significant brain damage. Each new survivor provided neurologists with further ammunition for localization, the belief that certain brain functions could be tied to particular regions of the brain.

Neurologist and Surgeon-General William Hammond sought to learn from these earlier wartime injuries by observing the postwar civilian patients under his care [7]. He noted that several patients exhibited writhing motions of the hands and feet and named these phenomena athetosis. Many patients with athetosis also seemed to frequently slur their speech, inspiring Hammond to consult existing records on neuroanatomy, such as Willis’s Cerebri anatome. He noticed that for each patient with athetosis, the arteries routing through the center of the skull were abnormal or damaged [7].

Previous neurological theories suggested that certain functions of the central nervous system are unique to specific areas of the brain. This rationale allowed Hammond to argue that patients with athetosis were sharing symptoms for a seemingly simple reason. Fine motor control, among other traits, is partially localized to the center of the brain, an area that Willis had christened the corpus striatum [4]. Neurologists still employ some of Hammond’s discoveries today; for example, the corpus striatum is known to regulate motor processes by inhibiting unnecessary motor signals[8].

Fraying Nerves: What Global War Taught Us About the Brain

Tragically, the bond between neuroscience and war began to yield disturbing and frequently unscientific results by eroding the ethical standards that guide medical research. In the midst of the Second World War, Nazi scientists at the Dachau concentration camp exploited political prisoners under the guise of medical research [9]. The most famous of these experiments is the Dachau Hypothermia Study, in which civilian prisoners were immersed in ice water until they lost consciousness at temperatures ranging from 2—12 ℃. Dachau researchers claimed that this study was conducted to better understand the biological impact of hypothermia, a condition characterized by a core body temperature of less than 35 ℃, on the hearts of German pilots who had fallen into the frigid waters of northern Europe [10]. 

Although this study did not explicitly examine brain response to low temperatures, it did attempt to understand the impact of extreme cold on the heart. Due to the brain’s reliance on oxygenation from the bloodstream, a loss of circulation causes rapid injury to the nervous system. The Dachau studies represent a significant failure of both ethics and science: the significant risk of this study to patients is compounded by a failure to satisfy the basic principles of medical research, neglecting, for example, to record all of the variations in cardiac activity prior to and following hypothermic treatment [10]. Due to the profane treatment of human beings, the Dachau Hypothermia study has since been named a war crime and a crime against humanity.

Occasionally, such medical atrocities and war crimes did produce scientific discovery. One gripping case study describes four-year-old Valentina Zacchini, who suffered from a loss of vision due to bilateral damage to her occipital lobe, which is the vision control center of the cerebral cortex [11]. Valentina experienced tremendous physical and psychological abuse at the hands of pediatrician Gerhardt Kujath, who recorded her progressively failing movement patterns, like—in the words of journalist Ernst Klee—a mere “research object” [12]. After her death at age nine, a research team autopsied Valentina’s brain and confirmed that her blindness was attributed to a damaged striate cortex [13]. This striate cortex, now referred to as the primary visual cortex, is known as the first division of the cerebral cortex to receive sensory input from the eyes [14]. Tragedies like Valentina’s story serve as a potent reminder that science can harm or heal, and it is up to us to utilize knowledge wisely and ethically.

Unfortunately, even after World War II, ethical principles have not always walked hand-in-hand with neuroscience. As the world shifted into the technological revolution of the mid 1900s, the United States and the Soviet Union entered into the geopolitical stalemate known as the Cold War. The U.S. found itself in a unique position following the Second World War: the conflict left our economy booming and our actual country largely untouched. The Soviets, on the other hand, suffered ninety times as many casualties as the Americans amid the remnants of a ravaged homeland [15]. 

Locked in bitter ideological opposition to one another, the U.S. and the U.S.S.R. sought out a means of securing victory without the vicious bloodshed of World War II: espionage. As the American government realized the potential for neuroscience to aid in espionage, the Central Intelligence Agency (CIA) initiated the highly illegal Project MKUltra, which was an experimental program that used neuroscience for the development of “mind control” techniques [16]. To satisfy this vision, the CIA tested a wide assortment of supposed interrogation techniques, the most notable being the powerful hallucinogenic drug LSD [17]. 

While MKUltra’s use of LSD did not produce the desired “mind control” effect, LSD remains one of the most potent psychedelic drugs known to modern science. It has earned this title by mimicking serotonin, a neurotransmitter that regulates mood and mental stability. In the MKUltra study, LSD bound to subjects’ central serotonin receptors and induced powerful hallucinations by overwhelming the brain’s normal signalling pathways [18]. The researchers then administered intense electroshock therapy while playing a constantly repeating sequence of recorded messages in a process known as psychic driving. The total ramifications of Project MKUltra on the individuals involved are still unknown today, but survivors have described their experience as being “mentally raped” without any “sense of solidarity”[17]. For America at large, this project represented a step forward in the relationship between the federal government, the military, and the scientific industries of war—a trio known as the military-industrial complex.

The Most Intimate Battlefield: The Brain and Modern Warfare

The modern era has seen the continued advancement of neurotechnology in warfare like never before. Few devices exemplify this trend more effectively than the Brain-Machine Interface (BMI, also known as Brain–Computer Interface, BCI), a union of hardware and software that allows the human brain to interact with a digital program at the speed of thought [19]. In 1973, Jacques Vidal published a landmark paper establishing the possibility of reading electrical biosignals from the brain as an indicator of predictive or responsive thought patterns [20]. Although methods of reading electrical thought patterns had been prominent for decades, Vidal’s genius laid the groundwork for a computerized BMI system that could actually identify these signals and translate them into commands in real time.

BMI truly found its place in the military-industrial complex in 2002, when the Defense Advanced Research Projects Agency (DARPA) began providing grants to a prosthetics development program at Duke University [21]. The Department of Defense hoped that BMI could be used to improve the quality of life for amputee soldiers (potentially enabling them to return to service) and that the findings might also be transferable to wearable combat weaponry [21]. The prosthetics division aimed to isolate electrical signals from the sensorimotor cortex, a brain tissue structure that maps and controls conscious bodily movement [22]. 

To understand how such a device works, one can imagine a person who has had their left hand amputated below the elbow and replaced with a mechanical prosthetic. If that person wishes to grasp a pencil, the designated “hand” area of the sensorimotor cortex would then fire an electrical signal, which could then be read by an electrode implanted in the brain. The electrode would recognize what this biological signal encodes and translate it into a digital signal, which the prosthetic hand reacts to by closing around the pencil [23]. BMI technology is one of the most significant products of neuroscience and war, as it has enormous potential today in both medical and military environments.

A perfect example of BMI application in warfare is the unmanned aerial vehicle (UAV), better known as the combat drone. UAVs have made an enormous impact on our society by revolutionizing shipping, communications, research, and warfare [24]. When drones were first introduced into war zones, they reduced the number of soldiers placed into immediate danger and solved a key concern of leading military thinkers. Even in modern conflicts such as the ongoing Russo-Ukrainian War, training soldiers as drone pilots has become a popular tactic for overpowering an enemy on the battlefield [25].

Yet this move towards drone warfare brings its own problems; namely, what does battle look like between two warring parties when each is armed with drones? This is where the BMI can come into play. By synchronizing drone flight and weaponry to the speed of instinct, pilots should bypass the time needed to physically maneuver their controllers and then can outpace any non-BMI drone pilot. In an era of drone warfare, this means that the combatant with a superior BMI system should outgun and defeat the combatant with an inferior BMI system. In some cases, having even a flawed BMI system may be enough to win a skirmish with opposing non-BMI drones [26]. Implicit in BMI drone conflict is a new kind of arms race, driven by intellect and complicit in warfare.

One way this neuroscientific arms race evolves is through electrode technology, as evidenced by neuromuscular electrical stimulation (NMES) nodes. The NMES transmits real-world drone-object collisions into electrical skin sensation via a force feedback mechanism, allowing pilots to subconsciously correct for flight errors on impulse [27]. Less nuanced force feedback mechanisms are common in video game controllers and in some commercial automobiles. The NMES is particularly interesting because it induces instinctive responses without putting additional stress on the pilot’s attention, enabling pilots to react to stimuli at an impressive speed.

In fact, speed is indeed the most important factor in improving survivability in warfare. Anna Gielas, an expert at the University of Oxford, praises BMI systems for reducing the critical life-threatening seconds that can stand between the brain and a computerized system [28]. However, she is also concerned by the looming ethical dilemmas at hand, namely, the issue of responsibility: if a traditional soldier fires a weapon and takes a life against orders, blame lies clearly with the soldier. If, however, a BMI misinterprets a subconscious electrical twitch or an imaginary, hypothetical strike as an attack command, then with whom does the fault lie? In other words, how responsible are we for our own thoughts?

Neuroethicists don’t have a complete answer to these questions right now, but what we can do is continue to learn about the past, present, and future of neuroscience in war. In his work The Life of Reason, philosopher George Santayana famously remarked that those “who cannot remember the past are condemned to repeat it” [29]. Historically, arms races have culminated in tragedy, frequently wrought with tension and strife. As this neuroscientific arms race picks up pace, we can continue digging for answers in research journals, medical records, and war reports. No one can say for certain what lies at the finish line—but we are running the race all the same.

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