Tubular-dorsal nervous system of chordates

Question

Is tubular-dorsal nervous system of chordates related to lateral or radial symmetry? How does that elucidate the complexity level of nervous system reached by the vertebrate evolutionary branch?

Answer 1

The dorsal and tubular nervous system of chordates is associated to the cephalization in such animals and to bilateral symmetry. The existence of neural integrating centers with concentration of neurons in the brains and spinal cord (that is, central nervous system, CNS) permitted the raise of the interaction complexity among such animals and the environment. Receptor (that is, afferent conduction) and efferent (or motor, regulatory and behavioral reactions) functions come out more sophisticated in the chordates due to presence of more well-developed neural networks. Such features have been preserved by the evolution as they give adaptive benefit to their owners.