A group of European researchers has developed a spinal cord model of the salamander and implemented it in a novel amphibious salamander-like robot. The robot changes its speed and gait in response to simple electrical signals, suggesting that the distributed neural system in the spinal cord holds the key to vertebrates complex locomotor capabilities.
In a paper appearing in the March 9, 2007 issue of the journal Science, scientists from the EPFL in Switzerland and the INSERM research center/University of Bordeaux in France introduce their robot, Salamandra Robotica. This four-legged yellow creature reveals a great deal about the evolution of vertebrate locomotion. Its also a vivid demonstration that robots can be used to test and verify biological concepts, and that very often nature herself offers ideal solutions for robotics design.
The researchers used a numerical model of the salamanders spinal cord to explore three fundamental issues related to this vertebrates movement: what were the changes in the spinal cord that made it possible to evolve from aquatic to terrestrial locomotion? How are the limb and axial movements coordinated? And how is a simple electrical signal from the brain stem translated by the spinal cord into a change in gait?
Once they thought they had answers to these questions, the team implemented the model a system of coupled oscillators representing the neural networks in the spinal cord on a primitive salamander-like robot. Simple electrical signals, like the signals sent from the upper brain to the spinal cord, were sent wirelessly from a laptop to the robot. These signals were enough to cause the robot to change its speed and direction and change from walking to swimming. The model therefore provides a potential explanation relevant for all four-legged organisms of how agile locomotion is controlled by distributed neural mechanisms located in the spinal cord.