A high-tech way to help the brain adapt to stressful conditions—and to normal life
Beach landings are a well-known specialty of the U.S. Marine Corps. But Marines are only human—even if they don't like to admit it—and like anyone else, they can't operate at their very best if they spend too much time in cold water. “Even after a few minutes, they'll perform tasks more slowly," says Weimin Zheng, Ph.D.
Zheng, a Leidos senior neuroscientist, has learned quite a bit about the effects of cold water on warfighter performance. That's thanks to a deceptively simple-seeming experiment he conducted with Marines in a high-altitude cold weather environment.
In the experiment, Marines spend several minutes in an icy pond, as part of their routine training courses, while performing cognitive tasks testing their response times and working memories. But they do it while wearing an unusual piece of gear: a headset that measures their brains' electrical activity.
The results should point the way to techniques for preserving a warfighter's ability to stay sharp even when the mission runs through the wetter side of the shoreline. But perhaps more importantly, the experiment could illuminate an entirely new—and potentially uniquely effective—approach to addressing a wide range of brain-related problems, including post-traumatic stress disorder, mild traumatic brain injury, depression, and more. And it could even open the door to improvements in how warfighters are trained for maximum performance in almost any austere condition.
Decoding brain activity
But the experiment's first and most important goal, notes Zheng, is simply learning some of the brain's most basic operating principles. “To solve problems with the brain, we need to know more about how the normal brain works," he explains. “And that means we need to learn its patterns of electrical activity, the main communication signal of the brain networks."
The cold-water experiments are already yielding crucial insights. After several minutes in the water, subjects' response times slow by about half a second. “After many years of research, the most prevalent view is that the slowdown is from muscles becoming rigid in the cold," says Zheng. “But we found that about two-thirds of the delay is from the brain slowing down. That's because the brain is conserving or reallocating energy to the most important tasks for the individual—namely, surviving the challenging of fatal cold exposure." He adds that the slowdown can be manifested with distinct changes in the patterns of brain waves—that is, the many different oscillation patterns in electrical signals that together underlie brain network functions.
Zheng is experimenting with simple changes, such as manipulating the sensory inputs to the brain, to see if the brain can be “tricked," as Zheng puts it, into more normal activity patterns. “The brain gets millions of signals per second from everything it sees and feels," he says. “Changing that input is sort of like negotiating with the brain."
But Zheng also has a more ambitious scheme in mind: applying mild electrical stimulation to help directly guide the brain activity toward normal patterns, which might in turn keep performance closer to peak levels. “That's my next step," he says.
If the results of those planned experiments in the thermal chamber prove promising, then the hope would be that other types of abnormal brain activity, such as those associated with almost any sort of mental health disorder or injury, might also be steered back toward normal patterns by stimulation in ways that alleviate symptoms. “The idea is to directly modify the brain's network by increasing some oscillations and damping others," he says. “Then we can observe any changes in behavior to see if we're on the right track."
Changing the brain's activity patterns may simply be a matter of modulating a natural process the brain undergoes when it's coping with some type of trauma or injury. “The brain isn't really hardware, it's very plastic, and it's constantly adapting to whatever daily life experience it's exposed to," notes Zheng. “If it's exposed to combat or other extremely stressful conditions, it adapts to that. Then, when the service member comes home, it can take a long time for the brain to readapt to more normal situations." Electrical stimulation, he adds, may be able to lend a helping hand by speeding up the process. And it might work just as well in addressing problems such as difficulty sleeping or anxiety.
But for the technique to work, Zheng will first have to develop a catalog of different patterns of brain activity across different regions of the brain to know exactly what type of electrical stimulation to apply and exactly where to apply it. “If we can do it in a targeted way, we may be able to make service members' brains more adaptive both to stressful conditions and to normal human experience," he says. The approach might eventually be useful in training, he adds, by learning how to achieve brain activity patterns associated with higher performance.
Of course, Zheng's research currently requires cumbersome, expensive equipment that wouldn't be practical outside a state-of-the-art neurolab. Eventually, if the exploratory work in the neurolab proves promising, he hopes to develop light, ultra-portable headsets that could be deployed in the field to measure brain activity and even apply any stimulation that might be helpful. “That's something I'll be working on for the next few years," he says. “There are still a lot of details to work out."
A state-of-the-art climate chamber, located at a Navy laboratory where Zheng has been leading a variety of brain research projects with both healthy and wounded warriors, provides an ideal laboratory to work out the details in different extreme climate conditions under which military missions are often conducted. For example, a newly launched project examining the effect of cold exposure on marksmanship could yield new strategies to enhance marksmanship in extremely cold environments.
Zheng asserts that investments in understanding how the brain works in both normal and austere conditions will be a key to success in modern warfare—and to protecting warfighters' well-being. "The more we know about how our brain works," he says, "the more we'll be able to enhance its performance, and to repair it when damage occurs."