The neurophysiological bases of undulatory locomotion in vertebrates

As a fish swims forwards, an, undulatory wave is transmitted along the body, pushing the animal forwards through the water. The underlying motor pattern consists of a consecutive activation of the muscle fibres in each segment along the body, forming an electromyographical travelling wave. The intersegemental coordination for both forward and backward swimming can be generated by neural circuitry in the brainstem-spinal cord and has already been identified experimentall. The evidence for two alternative hypotheses about the function of this circuitry is scrutinized.