Scientists find mind-body connection in the human brain – 04/21/2023 – Science

The relationship between the human mind and body is a subject that has challenged great thinkers for millennia, including the philosophers Aristotle and Descartes. The answer, however, seems to lie in the very structure of the brain.

Researchers said on Wednesday they found that parts of the brain region called the motor cortex, which governs body movement, are connected to a network involved in thinking, planning, mental alertness, pain and control of internal organs, as well as functions such as blood pressure and heart rate.

They identified a previously unknown system within the motor cortex manifested in several nodules located between areas of the brain already known to be responsible for the movement of specific parts of the body — hands, feet and face — and are triggered when several different body movements are performed at the same time. .

The researchers called this system the somatocognitive action network, or SCAN, and documented its connections to brain regions known to help set goals and plan actions.

It turned out that this network also corresponds to regions of the brain that, as shown in studies with monkeys, are linked to internal organs, including the stomach and adrenal glands, allowing these organs to change activity levels before performing certain actions. That could explain physical responses like sweating or an increased heart rate caused by the mere prospect of a difficult task, they said.

The motor cortex is a part of the outermost layer of the brain, the cerebral cortex.

“Basically, we’ve now shown that the human motor system is not unitary. Rather, we believe there are two separate systems that control movement,” said Evan Gordon, professor of radiology at Washington University School of Medicine in St. Louis. Louis, lead author of the study published in the journal Nature.

“One is for isolated movements of the hands, feet and face. This system is important, for example, for writing or speaking — movements that only need to involve one part of the body. A second system, the SCAN, is more important for body movements and is more linked to higher-level planning regions of the brain,” said Gordon.

“Modern neuroscience does not include any kind of mind-body dualism. It’s not compatible with being a serious neuroscientist today. I’m not a philosopher, but a succinct statement is like saying, ‘The mind is what the brain does. ‘ The sum of the brain’s bio-computational functions makes up ‘the mind,'” said study lead author Nico Dosenbach, professor of neurology at the University of Washington School of Medicine.

“Because this system, SCAN, appears to integrate abstract planes-thoughts-motivations with real movements and physiology, it offers an additional neuroanatomical explanation as to why ‘the body’ and ‘the mind’ are not separate or separable,” added Dosenbach.

The researchers decided to use modern brain imaging techniques to test an influential map laid out 90 years ago by neurosurgeon Wilder Penfield of the brain areas controlling movement. His discoveries showed that Penfield’s map, constrained by his time technologies, was in need of revisions.

SCAN was identified using precision imaging in seven adults to examine the brain’s organizational characteristics, then verified in larger datasets that, when combined, span thousands of adults. Additional imaging identified the SCAN circuit in an 11-month-old and a 9-year-old, while it was found that it had not yet formed in a newborn. These observations were validated against datasets of hundreds of newborns and thousands of 9-year-olds.

The research highlighted how there is more to learn about the human brain.

“Actually, the purpose of the brain is highly debated,” said Gordon. “Some neuroscientists think of the brain as an organ designed primarily to perceive and interpret the world around us. Others think of it as an organ designed to produce the best ‘outputs’ — usually a physical action — to optimize survival capacity and evolutionary fitness in any situation.”

“Probably both are correct,” added Gordon. “SCAN fits more clearly with the latter interpretation: it integrates goals and planning with full-body actions.”

Translated by Luiz Roberto M. Gonçalves