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 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 not unprecedented to have a stable system independently controlled by two or more masters. In fact, this is a common pattern known as a complex adaptive system. Scientists use an approach called network dynamics to study these systems in biology, ecology, economics, computer science, sociology and other disciplines.
As another example of a complex adaptive system, Petersen cites body temperature, which is regulated by several independent factors including sweat glands, metabolism and activity level. When one controlling factor goes awry, others can try to compensate for it.