The post-potential excitability modulation of alpha nerve and muscle fibers in human newborn and adult.
In order to assess indirectly the excitability of human motor units, the absolute refractory period of the ulnar nerve alpha motor fibers and the absolute irresponsive period of the abductor digiti minimi fibers were measured in 8 premature, 10 fullterm newborns and 10 adults. Results indicate that absolute refractory period of alpha motor nerve fibers appears to be a specific functional property of the membrane, independent of postnatal development. Moreover the maturation of muscle membrane seems slightly delayed in comparison to that of nerve fibers. Indeed the absolute irresponsive period of muscle fibers is slightly higher in premature in comparison with fullterm newborn and adult.
Duron
B
B
Laboratoire de Neurophysiologie, URA 1331 CNRS, Faculté de Médecine, Amiens, France.
Khater-Boidin
J
J
D000328:Adult; D000367:Age Factors; D005385:Fingers / Q000294:innervation; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D007234:Infant, Premature / Q000502:physiology; D024510:Muscle Development; D009132:Muscles / Q000502:physiology*; D012032:Refractory Period, Electrophysiological / Q000502:physiology*; D012508:Sarcolemma / Q000648:ultrastructure; D014459:Ulnar Nerve / Q000254:growth & development / Q000502:physiology*