Final answer:
PNS neurons have their embryonic origin from the neural crest cells that migrate away from the central nervous system during embryonic development.
Step-by-step explanation:
PNS neurons have their embryonic origin from the neural crest, which is a group of cells that migrates away from the developing central nervous system (CNS). These cells originate from the edge of the neural groove during embryonic development. As the neural folds come together and form the neural tube, the neural crest cells separate from the ectoderm and migrate to different parts of the embryo. Some of these neural crest cells differentiate into PNS neurons, while others contribute to non-nervous tissues.