Calm body, calm mind, say the practitioners of mindfulness. A new study by researchers at Washington University School of Medicine in St. Louis indicates that the idea that the body and mind are inextricably intertwined is more than just an abstraction. The study shows that parts of the brain area that control movement are plugged into networks involved in thinking and planning, and in control of involuntary bodily functions such as blood pressure and heartbeat. The findings represent a literal linkage of body and mind in the very structure of the brain.
The research, published April 19 in the journal Nature, could help explain some baffling phenomena, such as why anxiety makes some people want to pace back and forth; why stimulating the vagus nerve, which regulates internal organ functions such as digestion and heart rate, may 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, say, breathing exercises, you also calm your mind,” said first author Evan M. Gordon, PhD, an assistant professor of radiology at the School of Medicine’s Mallinckrodt Institute of Radiology. “Those sorts of practices can be really helpful for people with anxiety, for example, but so far, there hasn’t been much scientific evidence for how it works. But now we’ve found a connection. We’ve found the place 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 absolutely should have feedback effects on the other.”
Gordon and senior author Nico Dosenbach, MD, PhD, an associate professor of neurology, did not set out to answer age-old philosophical questions about the relationship between the body and the mind. They set out to verify the long-established map of the areas of the brain that control movement, using modern brain-imaging techniques.
In the 1930s, neurosurgeon Wilder Penfield, MD, mapped such motor areas of the brain by applying small jolts of electricity 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 specific body parts to twitch. Moreover, the control areas in the brain are arranged in the same order as the body parts they direct, with the toes at one end of each strip and the face at the other. Penfield’s map of the motor regions of the brain — depicted as a homunculus, or “little man” — has become a staple of neuroscience textbooks.
Gordon, Dosenbach and colleagues set about replicating Penfield’s work with functional magnetic resonance imaging (fMRI). They recruited seven healthy adults to undergo hours of fMRI brain scanning while resting or performing tasks. From this high-density dataset, they built individualized brain maps for each participant. Then, they validated their results 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 from about 50,000 people.