We presently lack a broad comparative understanding of the neuromuscular basis of lower vertebrate locomotor behavior. Notably, no previous study has quantitatively measured axial muscle activity in salamanders which are the most primitive extant tetrapodal vertebrates. The proposed research on fish and salamander locomotor behavior will simultaneously examine axial movements and the underlying patterns of muscle activity (the motor pattern). By comparing taxa with different shapes, numbers of body segments and limbed versus limbless animals, the influence of morphology on motor pattern will be assessed. By altering viscosity and determining the motor pattern for terrestrial and aquatic locomotion, the influence of the environment on the motor pattern will be determined. Comparisons of axial motor patterns over a wide range of speeds, taxa, and environmental conditions will allow examination of the plasticity of neural control in locomotor behaviors.
