The mind-body connection is built into the structure of the brain, study reveals

Calm body, calm mind, say mindfulness practitioners. A new study by researchers at Washington University School of Medicine in St. Louis indicates that the idea that body and mind are inextricably linked is more than just an abstraction. The study shows that the parts of the brain area that control movement are connected to networks involved in thinking and planning, and in controlling involuntary bodily functions such as blood pressure and heart rate. The results represent a literal connection of body and mind within the very structure of the brain.

The research, published April 19 in the journal Nature, could help explain some puzzling phenomena, such as why anxiety causes some people to pace; why stimulation of the vagus nerve, which regulates internal organ functions such as digestion and heart rate, can alleviate depression; and why people who exercise regularly report a more positive outlook on life.

People who meditate say that by calming your body with, for example, breathing exercises, you also calm your mind. These types of practices can be very helpful for people with anxiety, for example, but so far there hasn’t been much scientific evidence that they work. But now we have found a connection. We’ve found where the highly active, goal-oriented “go, go, go” part of your mind connects to the parts of the brain that control breathing and heart rate. If you calm one down, it should definitely have feedback effects on the other.”

Evan M. Gordon, PhD, first author, assistant professor of radiology at the School of Medicine’s Mallinckrodt Institute of Radiology

Gordon and lead author Nico Dosenbach, MD, PhD, associate professor of neurology, didn’t set out to answer age-old philosophical questions about the relationship between body and mind. They set out to verify the long-established map of brain areas that control movement, using modern brain imaging techniques.

In the 1930s, neurosurgeon Wilder Penfield, MD, mapped these motor areas of the brain by applying small electrical jolts to the exposed brains of people undergoing brain surgery and noting their responses. He discovered that stimulating a narrow strip of tissue on each half of the brain causes certain parts of the body to contract. Additionally, the control areas in the brain are arranged in the same order as the body parts they rule, with the toes at one end of each strip and the face at the other. Penfield map of motor regions of the brain -; represented as a homunculus, or “little man” -; has become a staple in neuroscience textbooks.

Gordon, Dosenbach and colleagues set out to replicate Penfield’s work with functional magnetic resonance imaging (fMRI). They recruited seven healthy adults to undergo hours of fMRI brain imaging while resting or performing tasks. From this high-density dataset, they constructed individualized brain maps for each participant. Next, they validated their findings using three large, publicly available fMRI datasets; the Human Connectome Project, the Adolescent Brain Cognitive Development Study and the UK Biobank -; which together contain brain scans of approximately 50,000 people.

To their surprise, they discovered that Penfield’s map was not quite correct. The foot control was where Penfield had identified. Same for hands and face. But interspersed with these three key areas were three other areas that didn’t seem to be directly involved in movement at all, even though they were in the motor area of ​​the brain.

Also, the non-movement zones looked different from the movement zones. They seemed thinner and were strongly connected to each other and to other parts of the brain involved in thinking, planning, mental arousal, pain, and controlling internal organs and functions such as blood pressure and heart rate. Other imaging experiments showed that while non-movement areas did not become active during movement, they did when the person was thinking about moving.

“All of these connections make sense if you think about what the brain is really for,” Dosenbach said. “The brain is for successfully behaving in the environment so that you can achieve your goals without injuring or killing yourself. You move your body for a reason. Of course, motor areas must be connected to executive function and control of basic bodily processes, like blood pressure and pain. Pain is the most powerful feedback, isn’t it? You do something, and it hurts, and you think, “I’m not going to do it again .””

Dosenbach and Gordon named their newly identified network the somato (body)-cognitive (mind) action network, or SCAN. To understand how the network has grown and evolved, they
scanned the brains of a newborn, a 1-year-old and a 9-year-old. They also analyzed data that had previously been collected on nine monkeys. The network was not detectable in the neonate, but was clearly evident in the 1-year-old and almost adult-like in the 9-year-old. Apes had a smaller, more rudimentary system without the extensive connections seen in humans.

“It may have started as a simpler system to integrate movement into physiology so that we don’t pass out, for example, when we stand up,” Gordon said. “But as we move into organisms that do much more complex thinking and planning, the system has been enhanced to incorporate many very complex cognitive elements.”

Clues to the existence of a mind-body network have been around for a long time, scattered in isolated papers and inexplicable sightings.

“Penfield was brilliant, and his ideas were dominant for 90 years, and that created a blind spot in the field,” said Dosenbach, who is also an associate professor of biomedical engineering, pediatrics, occupational therapy, radiology and psychological and brain sciences. “Once we started looking, we found a lot of published data that didn’t quite match his ideas, and alternative interpretations that had been overlooked. We gathered a lot of different data in addition to our own observations. , and zoomed out and synthesized it, and found a new way to think about how body and mind are connected.”