The “Two-Commander” Brain

Scientists have probed the upper echelons of the human brain's chain-of-command and have found that there are likely not one, but two complementary commanders in charge of the brain.

It is being compared to having Captains James T. Kirk and Jean-Luc Picard both “on the bridge and in command of the same starship Enterprise."

"This was a big surprise,” says senior author Steven Petersen, Ph.D., James S. McDonnell Professor of Cognitive Neuroscience and professor of neurology and psychology. “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."

Yeah professor, that’s what we all thought. How can one brain have two top dogs if there’s only one me? The scientists say that these two captains are networks of brain regions that do not consult each other, but work separately towards a common purpose. Together they control our voluntary, goal-oriented behavior. I guess they’re co-captains who don’t talk much, but have the same goals.

Nico Dosenbach, an M.D./Ph.D. student says they were surprised to find that while brain regions had multiple connections to other regions on their same side, they never connected to regions on the opposite side.

While seemingly strange, it is not unprecedented to have a stable system independently controlled by two or more masters. It is actually a common pattern known as a complex adaptive system. Scientists have long used network dynamics to study these systems in many disciplines including biology, ecology, economics, and computer science.

"This maps very nicely onto another idea that's common in network dynamics and adaptive systems," Dosenbach says. "This is the idea that the factors controlling adaptive systems often act on different time scales. We think the frontoparietal network may be the more online, rapid-adapting controller, while the cinguloopercular network is the more stable, set, in-the-background controller."

Dosenbach also points out why the “two commander” brain may have evolved. "It's amazing: on the one hand, the brain can be very flexible and rapidly adapt to changing feedback, but it can also lock in on something and tune out distractions until the task is finished. And these two separate control systems that work toward the same goal without actually talking to each other likely help create this powerful flexibility."

Posted by Rebecca Sato

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