The effects of target tissues on the outgrowth of chick cutaneous and muscle sensory neurons

A study of the presence and specificity of attraction between sensory axons and target tissues from chick hindlimbs during early development through retrograde labeling of muscle or cutaneous sensory neurons before three-dimensional collagen gel coculturing reveals that sensory neurons are attracted by the target cells, without any specificity. Diffusible factors secreted by muscle and dermis cells stimulate the sensory axons to migrate away from the plexus toward the target cells, forming discrete peripheral nerves.