We have now investigated the hind-limb reflex trajectory structure and motor pattern organization in the wiping reflex of more than 50 spinal frogs.
Individual frogs are very consistent.
However, frogs show significant inter-individual variation in trajectory straightness and motor program structure. Similarly the alterations following deafferentation vary. Our analysis shows all these individual variations can be accounted for by simple variations in a pattern generator and the afferent control of three force-field primitives. The force-field primitives encapsulate the behavior of specific synergies, their afferents and their heteronymous control patterns as a functional unit. We suggest such primitives are not part of, but are recruited by, the rhythm generator.