Two silver lampreys, Ichthyomyzon unicuspis, some of the most primitive existing vertebrates. The lamprey nervous system is being used as a model to develop prosthetic devices for people with spinal cord injuries. Image courtesy of Eric D. Tytell and Avis Cohen.
Scientists at the University of Maryland (UMD), College Park, and Tulane University (Tulane), New Orleans, Louisiana, have developed a computational model of a swimming fish that is the first to address the interaction of both internal and external forces on locomotion. According to a UMD press release, the interdisciplinary research team simulated how the fish’s flexible body bends, depending on both the forces from the fluid moving around it as well as the muscles inside. The researchers say that understanding these interactions and general principles of animal movement, even in fish, could help design and inspire robots and medical prostheses for humans that work with the body’s natural mechanics, rather than against them.
Eric D. Tytell, PhD, a UMD post-doctoral researcher, conducted this research in the UMD laboratory of Avis Cohen, PhD, a Department of Biology and Institute for Systems Research professor. Chia-yu Hsu, PhD, a Tulane postdoctoral researcher, and Tytell performed simulations with different values for various body and fluid properties, using the lamprey, a primitive vertebrate whose nervous system Cohen and colleagues are using as a model to develop prosthetic devices for people with spinal cord injuries.
“The devices may one day help people regain control over their legs and walk again,” Cohen said. “We understand to first order the neural circuit that controls the muscles for swimming or walking. Now, for neuroprosthetics, we need to understand how the muscles interact with the body and the environment-our model helps us do that.”
Tytell’s and Hsu’s research also provides biologists with quantitative information that can be applied to understand the biodiversity and evolution of fishes. The team plans to continue working with the model, using it to examine why different fishes are shaped differently and to also simulate sensory systems to try to figure out how fish maneuver so agilely through turbulent water.
“The first line of defense against external perturbations such as eddies in the water for fishes, or tripping on a rock for humans, isn’t the nervous system, but rather the body’s mechanics, kind of like the shocks on a car,” Tytell said. “If we can translate the mechanical stability that living organisms exhibit into the design of robots or prosthetics, we could really advance the technology.”
This research was published in the October 18, 2010, online early edition of the Proceedings of the National Academy of Sciences.
