Mismatches between peripheral receptor type and central projections after peripheral nerve regeneration

The central projections of axotomized fibers were assessed to investigate how well these matched the modality of the reinnervated receptor. Our results using intrafiber injection of horseradish peroxidase (HRP) and cord dorsum potentials evoked by intracellular stimulation of single afferents indicate that regenerating fibers can innervate inappropriate receptors. Mismatches included: (i) reinnervation of muscle receptors by cutaneous afferents, and vice versa; (ii) reinnervation of low threshold cutaneous receptors by nociceptive afferents; and (iii) reinnervation of slowly adapting receptors by fibers normally supplying rapidly adapting receptors.