A probe of the upper echelons of the human brain's chain-of-command has found strong evidence that there are not one but two complementary commanders in charge of the brain, according to neuroscientists at Washington University School of Medicine in St. Louis.
Scientists exploring the upper reaches of the brain's command hierarchy were astonished to find not one but two brain networks in charge, represented by the differently-colored spheres on the brain image above. Starting with a group of several brain regions.
Scientists exploring the upper reaches of the brain's command hierarchy were astonished to find not one but two brain networks in charge, represented by the differently-colored spheres on the brain image above. Starting with a group of several brain regions implicated in top-down control (the spheres on the brain), they used a new brain-scanning technique to identify which of those regions work with each other. When they graphed their results (bottom half), using shapes to represent different brain regions and connecting brain regions that work with each other with lines, they found the regions grouped together into two networks. The regions in each network talked to each other often but never talked to brain regions in the other network.
It's as if Captains James T. Kirk and Jean-Luc Picard were both on the bridge and in command of the same starship Enterprise.
In reality, these two captains are networks of brain regions that do not consult each other but still work toward a common purpose — control of voluntary, goal-oriented behavior. This includes a vast range of activities from reading a word to searching for a star to singing a song, but likely does not include involuntary behaviors such as control of the pulse rate or digestion.
"This was a big surprise. We knew several brain regions contribute to top-down control, but most of us thought we'd eventually show all those regions linking together in one system, one little guy up top telling everyone else what to do," says senior author Steven Petersen, Ph.D., James S. McDonnell Professor of Cognitive Neuroscience and professor of neurology and psychology.
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