We are interested in animal locomotion and would like to make robots to study
animal locomotion. Because animal locomotion is a very interesting interplay between the
body, the spinal cord and the environment. But to understand this interaction, we
really need a body and that's where the robot is a key tool. So we designed a
salamander robot that very closely mimics the real motion of the real
salamander, and it can both walk and swim
exactly like the real salamander. It's a very old animal, it's an amphibian and
it's almost a living fossil of the first terrestrial vertebrates,
so the ancestor of vertebrates like us, mammals. So by studying the salamander we
can study this key moment in evolution, the switch from swimming to walking,
and especially how the spinal cord has
reorganized itself to allow a new mode of locomotion.
So the novelty of this work is really the approach we took two to try to be
as close as possible to the real physics of the body.
The species is called Pleurodeles. We looked at detailed
x-ray recordings from the animals so we could track the bones in 3d space and
that enabled us to create a very detailed model of the movements of the
bones of the animal.
Neurobiologists have shown that if you electrically stimulate the spinal cord,
at low level of stimulation, it will induce a walking like gait. If you stimulate a bit
more, this gate accelerates, and at some point there's a threshold and it switches to
swimming so just changing the global drive that the brain sends to the spinal
cord makes a complete switch between different modes of the locomotion.
So understanding this is very important, for instance, for neuroprosthetics.
Being able to re-stimulate those circuits in humans in the long term is
something very important and for that you need to understand how the spinal
cord works.