Modulating Processes of Single Fusimotor Fibre Discharge in Man

  • J. P. Vedel
  • J. P. Roll


Experiments were performed on awake human subjects in which single nerve fibre activity was recorded in the lateral peroneal nerve using tungsten microelectrodes as described by Hagbarth & Vallbo (1967).

This discharge of thirteen single efferent fibres innervating the tibialis anterior muscle (TA) or the extensor digitorum longus muscle (EDL) was recorded. On the basis of their functional activity, seven fibres were identified as fusimotor fibres.

Their efferent nature was demonstrated by the fact that the various tests used to identify afferent fibres elicited no response of these fibres. These efferent fibres were considered as fusimotor because their discharges were uncorrected with any activation of extrafusal muscle fibres. Several means were used to detect activation of extrafusal fibres: surface EMG electrodes, tungsten electrodes deeply implanted in the muscle and especially the use of a high-sensitivity tension transducer (0.1 mN) placed on muscle tendons. Fusimotor fibres were generally spontaneously active with some fluctuation in the discharge frequency.

The activity in fusimotor fibres could be either elicited or modulated under the following conditions: clenching of the fists, pinna twisting, voluntary isometric contraction, passive phasic stretch of the muscle, mental computation, environmental disturbances, subject laughing, the sound of hand clapping, and subject listening to manoeuvre instructions. Moreover, during spontaneous fusimotor fiber activity two subjects were able to voluntarily stop the unit discharge.

The results are compared to those obtained in animal studies and discussed with reference to the notion of alpha-gamma linkage, static and dynamic gamma motoneuron activities, and to another available data concerning the effects of various stimulations on muscle spindle afferent activities in man.


Tibialis Anterior Extensor Digitorum Longus Muscle Spindle Muscle Nerve Sympathetic Activity Mental Computation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Appelberg, B., Hulliger, M., Johansson, H., and Sojka, P. C., 1983, Actions on gamma-motoneurons elicited by electrical stimulation of muscle group I afferent fibres in the hindlimb of the cat, J. Physiol., 335: 237–253.PubMedGoogle Scholar
  2. Appenteg, K., Hulliger, M., Prochazka, A., and Zangger, P., 1983, Fusimotor action during movement, deduced by matching the pattern of afferent discharge in freely moving and anaesthetized cats, J. Physiol., 334: 29–30.Google Scholar
  3. Boyd, I. A., 1981, The action of the three types of intrafusal fibres in isolated cat muscle spindle on the dynamic and length sensitivities of primary and secondary sensory endings, in: Taylor, A., Prochazka, A, Eds., “Muscle receptors and movement”, MacMillan, London, pp. 17–32.Google Scholar
  4. Boyd, I. A., Gladden, M. H., McWilliam, P. N., and Ward, J., 1977, Control of dynamic and static nuclear bag fibres and nuclear chain fibres by gamma and beta axons in isolated cat muscle spindles, J. Physiol. 265: 133–162.PubMedGoogle Scholar
  5. Brown, M. C., and Matthews, P. B. C., 1966, On the subdivision of efferent fibres to muscle spindle into static and dynamic fusimotor fibres, in: Andrew, B.L., Ed., “Control and innervation of skeletal muscle”, Truex, Oxford, pp. 18–31.Google Scholar
  6. Burke, D., 1981, The activity of human muscle spindle endings in normal behaviour, Int. Rev. Physiol., 20: 91–136.Google Scholar
  7. Burke, D., Hagbarth, K. E., and Lofstedt, L., 1978a, Muscle spindle responses in man to changes in load during accurate position maintenance, J. Physiol., 276: 159–164.PubMedGoogle Scholar
  8. Burke, D., Hagbarth, K. E., and Lofstedt, L., 1978b, Muscle spindle activity in man during shortening and lengthening contractions, J. Physiol., 277: 131–142.PubMedGoogle Scholar
  9. Burke, D., Hagbarth, K. E., and Skuse, N., 1979, Voluntary activation of spindle endings in human temporarily paralysed by nerve pressure, J. Physiol., 287: 329–336.PubMedGoogle Scholar
  10. Burke, D., MacKeon, B., and Westerman, R. A., 1980, Induced changes in the threshold for activity in preparation for a voluntary contraction, J. Physiol., 302: 171–181.PubMedGoogle Scholar
  11. Burke, D., Sundlof, G., and Wallin, G., 1977; Postural effects on muscle nerve sympathetic activity in man, J. Physiol., 272: 399–414.PubMedGoogle Scholar
  12. Burke, D., Hagbarth, K. E., Lofstedt, L., and Wallin, B. G., 1976a, The response of human muscle spindle endings to vibration of non-contracting muscles, J. Physiol., 261: 673–693.PubMedGoogle Scholar
  13. Burke, D., Hagbarth, K. E., Lofstedt, L., and Wallin, B. G., 1976b, The response of human spindle endings to vibration during isometric contraction, J. Physiol., 277: 131–142.Google Scholar
  14. Burke, D., McKeon, B., Skuse, N.F., and Westerman, R. A., 1980, Anticipation and fusimotor activity in preparation for a voluntary movement, J. Physiol., 306: 337–348.PubMedGoogle Scholar
  15. Crowe, A., and Matthews, P. B. C., 1964, The effects of stimulation of static and dynamic fusimotor fibres on the response to stretching of the primary endings of muscle spindles, J. Physiol., 174: 109–131.PubMedGoogle Scholar
  16. Delius, W., Hagbarth, K. E., Hongell, A., and Wallin, B. G., 1972a, General characteristics of sympathetic activity in human nerves, Acta Physiol. Scand., 84: 65–81.PubMedCrossRefGoogle Scholar
  17. Delius, W., Hagbarth, K. E., Hongell, A. and Wallin, B. G., 1972b, Manoeuvres affecting sympathetic outflow in human skin nerves, Acta Physiol. Scand., 84: 177–186.PubMedCrossRefGoogle Scholar
  18. Ellaway, P. H., and Trott, J. R., 1976, Reflex connections from muscle stretch receptors to their own fusimotor neurons, Prog. Brain Res., 44: 113–122.PubMedCrossRefGoogle Scholar
  19. Ellaway, P. H., and Trott, J. R., 1978, Autogenic reflex action onto gamma motoneurons by stretch of triceps surae in the decerebrate cat, J. Physiol., 276: 49–66.PubMedGoogle Scholar
  20. Ellaway, P. H., Pascoe, J. E., and Trott, J. R., 1976, The effects upon fusimotor neurons on small, brief stretches of their muscles, J. Physiol., 258: 48–49.Google Scholar
  21. Emonet-Dénand, F., Hunt, C. C., and Laporte, Y., 1985a, Fusimotor after-effects on responses of primary endings to test dynamic stimuli in cat muscle spindles, J. Physiol., 360: 187–200.PubMedGoogle Scholar
  22. Emonet-Dénand, F., Hunt, C. C., and Laporte, Y., 1985b, Effects of stretch on dynamic fusimotor after-effects in cat muscle spindles, J. Physiol., 360: 201–223.PubMedGoogle Scholar
  23. Fromm, C., and Noth, J., 1974, Autogenetic inhibition of gamma motoneurons in the spinal cat uncovered by DOPA injection, Pflügers Archiv für die ges. Physiol., 349: 247–256.CrossRefGoogle Scholar
  24. Fromm, C., Haase, J., and Noth, J., 1974, Length-dependent autogenetic inhibition of extensor gamma motoneurons in the decerebrate cat, Pflügers Archiv für die ges. Physiol., 363: 81–86.CrossRefGoogle Scholar
  25. Granit, R., Job, C., and Kaada, B. R., 1952, Activation of muscle spindle in pinna reflex, Acta Physiol Scand., 27: 161–168.PubMedCrossRefGoogle Scholar
  26. Hagbarth, K. E., 1952, Excitatory and inhibitory skin area for flexor and extensor motoneurons, Acta Physiol Scand. (suppl. 94), 26: 1–58.CrossRefGoogle Scholar
  27. Hagbarth, K. E., 1979, Exteroceptive, proprioceptive and sympathetic activity recorded with microelectrodes from human peripheral nerves, Mayo Clinic Proc, 54: 353–365.Google Scholar
  28. Hagbarth, K. E., and Vallbo, A. B., 1967, Mechanoreceptor activity recorded percutaneously with semimicroelectrodes in human peripheral nerves, Acta Physiol Scand., 69: 121–122.PubMedCrossRefGoogle Scholar
  29. Hagbarth, K. E., and Vallbo, A. B., 1968, Pulse and respiratory grouping of sympathetic impulses in human muscle nerves, Acta Physiol Scand., 74: 96–108.PubMedCrossRefGoogle Scholar
  30. Hagbarth, K. E., Wallin, G., and Lofstedt, L., 1975, Muscle spindle activity in man during voluntary fast alternating movements, J. Neurol. Neurosurg. and Psvchiat, 38: 1143–1153.CrossRefGoogle Scholar
  31. Hallin, R. G., and Torebjork, H. E., 1974, Single unit sympathetic activity in human skin nerves during rest various manoeuvres, Acta Physiol. Scand., 92: 303–317.PubMedCrossRefGoogle Scholar
  32. Henneman, E., Somjen, G., and Carpenter, P. O., 1965a, Functional significance of cell size in spinal motoneurons, J. Neurophys., 28: 560–580.Google Scholar
  33. Henneman, E., Somjen, G., and Carpenter, P. O., 1965b, Excitability and inhibitibility of motoneurons of different sizes, J. Neurophys., 28: 599–620.Google Scholar
  34. Henneman, E., and Mendell, L. M., 1981, Functional organization of motoneuron pool and its inputs, in.: Brookhart, J.M., Mountcastle, V.B., and Brooks, V.B., Eds., “Motor control (part 1), Handbook of Physiology”, sect. 1, vol. 2, American Physiological Society, Bethesda, pp 423–507.Google Scholar
  35. Hulliger, M., 1984, The mammalian muscle spindle and its central control Rev. Physiol. Bioch. Pharmacol., 101: 110 pp.Google Scholar
  36. Jendrassik, E., 1883, Beiträge zur Lehre von den Sehnenreflexen, Statist Archiv für Klin. Med., 33: 177–199.Google Scholar
  37. Laporte, Y., 1978, The motor innervation of the mammalian muscle spindle, in: Porter R., Ed., Studies in Neurophysiology presented to McIntyre A.K., Cambridge University Press, pp 45–59.Google Scholar
  38. Laporte, Y., 1979, Innervation of cat muscle spindles by fast-conducting skeletomotor fibres, in: Asanuma H., Wilson V.J., Eds., “Integration in the nervous system”, Igaku-Shoin, Tokyo, pp 3–12.Google Scholar
  39. Lundberg, A., Winsbury, G., 1960, Selective adequate activation of large afferents of muscle spindles and golgi tendon organs, Acta Physiol Scand., 49: 155–164.PubMedCrossRefGoogle Scholar
  40. McCloskey, D. I., 1978, Kinesthetic sensibility, Physiol Rev., 58: 768–820.Google Scholar
  41. Matthews, P. B. C. 1972, Mammalian muscle receptors and their central action, Monographs of the Physiological Society, Edward Arnold Ldt., London, 630 pp.Google Scholar
  42. Matthews, P. B. C., 1977, Muscle afferents and kinaesthesia, British Med. Bull 33: 137–142.Google Scholar
  43. Matthews, P. B. C., 1981a, Evolving views on the internal operation and functional role of the muscle spindle, J. Physiol., 320: 1–30.PubMedGoogle Scholar
  44. Matthews, P. B. C., 1981b, Muscles spindles: their messages and their motor supply, in: Brookhart, J.M., Mountcastle, V.B., and Brooks, Y.B., Eds., “Motor control, part 1, Handbook of Physiology”, sect 1, vol. 2, American Physiological Society, Bethesda, pp 189–228.Google Scholar
  45. Murthy, K. S. K., 1978, Vertebrate fusimotor neurons and their influences on motor behavior, Prog. in Neurobiol, 11: 249–307.CrossRefGoogle Scholar
  46. Normell, L. A., and Wallin, B. G., 1974, Sympathetic skin nerve activity and skin temperature changes in man, Acta Physiol. Scand., 91: 417–426.PubMedCrossRefGoogle Scholar
  47. Paillard, J., 1955, Réflexes et régulations d’origine proprioceptive chez l’Homme, Etude neurophysiologique et psychophysiologique, Thèse de Doctorat d’Etat, Arnette, Paris, 293 pp.Google Scholar
  48. Paillard, J., 1959, Functional organization of afferent innervation studies in man by monosynaptic testing, Am. J. Phys. Med., 38: 239–247.PubMedGoogle Scholar
  49. Prochazka, A., and Wand, P., 1981, Independence of fusimotor and skeletomotor systems during voluntary movement, in.: Taylor, A., and Prochazka, A., Eds., “Muscle receptors and movement”, McMillan Ldt., London, pp 229–243.Google Scholar
  50. Prochazka, A., and Hulliger, M., 1983, Muscle afferent function and its significance for motor control mechanisms during voluntary movement in cat, monkey and man, in: Desmedt, J.E., Ed., “Motor control mechanisms in health and disease”, Raven Press, New York, pp 93–132.Google Scholar
  51. Ribot, E., Roll, J. P., and Vedel, J. P., 1986, Efferent discharges recorded from single skeletomotor and fusimotor in man, J. Physiol., 375: 251–268.PubMedGoogle Scholar
  52. Roll, J. P., and Vedel, J. P., 1982, Kinaesthetic role of muscle afferents in man, studied by tendon vibration and microneurography, Exp. Brain Res., 47: 177–190.PubMedCrossRefGoogle Scholar
  53. Ruffini, A., 1898, On the minute anatomy of the neuromuscular spindles of the cat, and on their physiological significance, J. Physiol., 23: 190–208.PubMedGoogle Scholar
  54. Stuart, D. G., Mosher, C. G., Gerlach, R. L., and Reinking, R. M., 1970, Selective activation of la afferents by transient muscle stretch, Exp. Brain Res., 10: 177–187.Google Scholar
  55. Sundlof, G., and Wallin, B. G., 1977, The variability of muscle nerve sympathetic activity in resting recumbent man, J. Physiol. 272: 383–397.PubMedGoogle Scholar
  56. Taylor, A., and Appenteg, A., 1981, Distinctive modes of static and dynamic fusimotor drive in jaw muscles, in: Taylor, A., Prochazka, A., Eds., “Muscle receptors and movement”, McMillan, London, pp 179–192.Google Scholar
  57. Trott, J. R., 1976, The effect of low amplitude vibration on the discharge of fusimotor neurons in the decerebrate cat, J. Physiol., 255: 635–650.PubMedGoogle Scholar
  58. Vallbo, A. B., 1971, Muscle spindle response at the onset of voluntary isometric contractions in man, Time difference between fusimotor and skeletomotor effects, J. Physiol., 218: 405–431.PubMedGoogle Scholar
  59. Vallbo, A. B., 1974, Human muscle spindle discharge during isometric voluntary contractions, Amplitude relations between spindle frequency and torque, Acta Physiol Scand., 90: 303–318.PubMedCrossRefGoogle Scholar
  60. Vallbo, A. B., and Hulliger, M., 1981, Independence of skeletomotor and fusimotor activity in man, Brain Res., 223: 176–180.PubMedCrossRefGoogle Scholar
  61. Vallbo, A. B., Hagbarth, K. E., Torebjork, H. E., and Wallin, B. G., 1979, Somatosensory, proprioceptive and sympathetic activity in human peripheral nerves, Physiol. Rev., 59: 919–957.PubMedGoogle Scholar
  62. Vedel, J. P., and Roll, J. P., 1983, Muscle spindle contribution to the coding of motor activities in man, in: Massion, J., Paillard, J., Schultz, W., and Wiesendanger, M., Eds., “Neural coding of motor performance”, Springer Verlag, Berlin, Heidelberg, New York, Exp. Brain Res., Suppl. 7, pp 253–265.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1988

Authors and Affiliations

  • J. P. Vedel
    • 1
  • J. P. Roll
    • 2
  1. 1.Laboratoire de Neurosciences FonctionnellesCNRSMarseille Cedex 9France
  2. 2.Département de Psychophysiologie, Laboratoire de Neurobiologie Humaine, UA CNRS 372Université d’Aix-MarseilleMarseille Cedex 13France

Personalised recommendations