Recent work by Bradley L. Schlaggar and Steven Peterson of the Washington University School of Medicine in St. Louis suggests that two independent control centers manage our voluntary, goal-oriented behavior. One is flexible and rapidly adapts to changing feedback. The other can focus in on something and tune out distractions until the task is finished.

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.

This is seen as an example of a class of systems known as complex adaptive systems, common both in nature and even other bodily systems such as temperature control.

Subsequent research now indicates that these two systems begin as one system in children and only differentiate into two independent systems as we mature. This suggests, among other things, why children are unable to resist impulse behaviors that hurt their long-term goals. The longer term network is “clamped” inside the network that rapidly adapts and is only able to fully express itself once it effectively separates out.

Links:

Brain’s voluntary chain-of-command ruled by not one but two captains

Brain’s control network splits in two as children approach adulthood