Neural activity originating from a neuroma in the baboon

Single nerve fiber recordings were obtained from traumatically induced neuromas of the superficial radial nerve in baboons 1-7 months after injury. Eight to 18% of the fibers had spontaneous activity, and 67% of these were unmyelinated. Myelinated as well as unmyelinated fibers responded to mechanical stimulation of the neuroma whereas no fibers responded to similar stimulation of the normal nerve. Apparent crosstalk of action potential activity between fibers at the neuroma was observed which could be due to electrical coupling, though retrograde sprouting is another possible explanation. These abnormalities in neural activity originating from a neuroma in the primate are qualitatively similar to those noted in other species and may provide an explanation for certain abnormal sensory phenomena associated with peripheral nerve injury.