Researchers Produce a Computational Model of Swimming Fish to FurtherDevelop Prostheses for Humans

Researchers at the University of Maryland created a computational model
of a swimming fish by using the central nervous system of a lamprey. In order
to understand how internal and external forces affect locomotion, researchers
studied and simulated how a lamprey contorts and moves with the water around

According to Eric D. Tytell, PhD, postdoctoral researcher in the
department of biology at the University of Maryland, studying the muscles of a
lamprey as they swim through the water may help researchers develop prosthetic
designs in the long term. The computational model was created in order to
develop prostheses that work more smoothly in conjunction with the human
body’s natural movements.

But why fish? While unique, this type of research is not that novel,
according to Tytell. Tytell’s supervisor at the time of the research, Avis
Cohen, PhD, has worked with lampreys and neural prosthetic designs in the past.

“The reason why she got started is that they are vertebrates like
you and me but with a simpler nervous system,” Tytell explained.

The ultimate goal of this research is to understand how the nervous
system interacts with a mechanical system, the body and the external

“That is just easier to do in an animal that has a central nervous
system,” Tytell said. “But unlike researchers who work with something
like a fly that also has a simple central nervous system, lampreys have the
same basic structure as a human’s nervous system.”

One of the most interesting aspects of the study, according to Tytell,
is that the movement of an animal is really interplay between the nervous
system and the body.

“You kind of think your brain is in control of what your body does,
but in fact we found that if the mechanics of the body change — even not
much — that our simulated fish can do fairly different things,”
Tytell explained. “It can go from accelerating rapidly to accelerating
slowly but swimming efficiently with exactly the same output from the nervous

The long-term goal of this research is to eventually develop prostheses
that are more fluid and realistic for the amputee.

“It is thinking about these questions of the interactions between
ctions in an intelligent way.
That’s sort of our long-term goal. In the short term, do not forget about
mechanics.” — by Anthony Calabro


Lampreys, if you look at the evolution of vertebrates, are at the bottom
of the vertebrate tree. But it has all of the characteristics of a good
vertebrate. Next to it is the hagfish, but hagfish are quite different. From
the lamprey, one can get evolutionarily up to humans, so to speak. The motor
control issues are pretty much indistinguishable. One could look for principals
of motor control that will hold by working with lampreys. I look for principals
and systems … which are going to hold more complex answers. Tytell takes
the principals and puts it all together.

Although this type of research can not be used for the limb, it provides
insight into coordination and the interrelation of motor output mechanics in an
environment. It is not a direct type of relation, but this type of research
does provide insight and testable hypotheses which then could be used for more
research in prosthetics.

— Avis H. Cohen, PhD
Director, ADVANCE
program for inclusive excellence, department of biology and institute for
systems research, University of Maryland

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