Changes in the central projection pattern of vibrissae innervating primary sensory neurons after peripheral nerve injury in the rat.

The central representation of a normal vibrissa nerve and the corresponding nerve after transection and regeneration of the infraorbital nerve has been studied by the use of transganglionic transport of horseradish peroxidase in the adult rat. The normal vibrissa nerve terminated in a well-defined area within nucleus caudalis and C1 dorsal horn. In contrast, the regenerated vibrissa nerve showed a widespread central termination pattern indicating a pronounced loss of somatotopic organization. These changes in somatotopic organization could contribute to an inability to correctly localize a sensory stimulus; this is a common clinical finding after peripheral nerve injury and regeneration.