Mind and Muscles in Constant Dialogue

Walking and chewing gum at the same time is more complex than it seems

PHOTO: Mike Scott

Hillel Chiel

You're walking on a sidewalk with muscles and nervous system working together seamlesslyuntil an unseen patch of ice nearly sends you careening to the ground. But most of the time, it doesn't.

Without conscious thought, you instantly adjustthen keep walking. What just happened?

The short answer is your body engaged in "adaptive behavior," or what Hillel Chiel, PhD, a Case Western Reserve biology professor, said is "making the right move at the right time."

He's focused on better understanding the precise brain-muscle interactions that swiftly occur to adjust to unexpected changesand then applying that knowledge to aid a range of developments, from more adaptive and flexible robots to more responsive prosthetic devices to brain-computer interfaces that create communications pathways between a brain and an electronic device.

To understand more complex neural-muscular connections, Chiel studies simpler interactions in the Aplysia californica sea slugspecifically the way it changes its chewing movements before each swallow to adapt to the varying toughness, size and texture of seaweed.

PHOTO: Joel Sartore/ National Geographic Photo Ark

Aplysia californica

Chiel's team has used MRI technology to watch the muscles in action. Now it's using electrodes to observe changing nerve-cell activity as sea slugs bite, swallow and reject food.

Chiel shares his know-how in multiple collaborative projects. He's working with CWRU engineering colleagues to develop soft-bodied robots that flexibly adapt to changing environments and could be used for search-and-rescue missions inside a pile of rubble after a fire, or to examine water mains for leaks.

He's also working with researchers on campus and at Vanderbilt University on using infrared laser light to switch off activity in axons, which are the threadlike parts of nerve cells that, among other things, carry pain signals. Halting the signals could potentially provide a treatment alternative to opioids.

"Research on adaptive behavior is actually a deep, fundamental, scientific quest to understand the behavior and abilities we absolutely take for granted," Chiel said. "You often don't realize how amazing they are until you lose themor if you're trying to program that kind of ability into a robot, for example."

— Andrew Faught