[Neuronal regeneration and functional recovery following peripheral nervous system lesions]

The complete traumatic sectioning of peripheral nerves start subcellular and molecular processes in the involved sensory and motor neurons that ends, in many cases, with a complete reinnervation of the sensory or muscular target. Nevertheless, the process is frequently disturbed, from a functional point of view, by the improper reinnervation of targets different from the original ones, a fact implying a partial or total lost of the involved sensory or motor function.

Results obtained with several types of axotomy and of experimental anastomosis carried out with the different brainstem motor nerves are shown. The aim was to analyze the capabilities of the different brainstem centers to adapt their physiology to the functional characteristics of a new motor target, with respect to their affinity with the motor tasks carried out by the new target.

It is concluded that there is a gradient of functional adaptability in motoneurons to the role of new motor targets depending on their affinity in embryologic origins and functional properties. It is remarked the importance that, for a proper recovery of the lost function, have the compensatory processes started by synergistic motor systems not affected directly by the lesion.