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. 1980 Aug;305:415–431. doi: 10.1113/jphysiol.1980.sp013373

Fusimotor activity in masseter nerve of the cat during reflex jaw movements.

K Appenteng, T Morimoto, A Taylor
PMCID: PMC1282982  PMID: 6449592

Abstract

1. Unit recordings have been made from the central ends of filaments of the masseter nerve in lightly anaesthetized cats. Evidence is presented to show that fusimotor activity may be distinguished from alpha motor activity. 2. During reflex cyclic movements induced by intra-oral stimulation, two distinct patterns of fusimotor firing emerged. One type of unit increased firing at the beginning and sustained this with little modulation throughout the movements. The other type was strongly modulated approximately in parallel with the alpha motor activity. 3. By comparison with records of jaw elevator spindle afferents under similar conditions, it was deduced that the sustained type of action was due to dynamic fusimotor neurones while the modulated type was due to static fusimotor neurones. 4. The patterns of fusimotor activity seen in these rhythmic movements under light anaesthesia agree well with the patterns deduced from spindle recordings in the conscious cat during mastication. 5. The results emphasize the importance of looking beyond a simple hypothesis of 'alpha-gamma co-activation' to explain fusimotor function. It is proposed that tonic dynamic fusimotor activity is set at the beginning of a movement to determine the incremental sensitivity of primary endings to stretch. The static fusimotor fibres are activated principally during shortening to help keep both primary and secondary endings active.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. ALNAES E., JANSEN J. K., RUDJORD T. FUSIMOTOR ACTIVITY IN THE SPINAL CAT. Acta Physiol Scand. 1965 Mar;63:197–212. doi: 10.1111/j.1748-1716.1965.tb04060.x. [DOI] [PubMed] [Google Scholar]
  2. Appenteng K., Morimoto T., Taylor A. Different behaviour of fast and slow efferents to masseter muscle in reflex movements in the cat [proceedings]. J Physiol. 1979 Aug;293:44P–44P. [PubMed] [Google Scholar]
  3. Appenteng K., O'Donovan M. J., Somjen G., Stephens J. A., Taylor A. The projection of jaw elevator muscle spindle afferents to fifth nerve motoneurones in the cat. J Physiol. 1978 Jun;279:409–423. doi: 10.1113/jphysiol.1978.sp012353. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Bergmans J., Grillner S. Changes in dynamic sensitivity of primary endings of muscle spindle afferents induced by DOPA. Acta Physiol Scand. 1968 Dec;74(4):629–636. doi: 10.1111/j.1748-1716.1968.tb04273.x. [DOI] [PubMed] [Google Scholar]
  5. Bergmans J., Grillner S. Reciprocal control of spontaneous activity and reflex effects in static and dynamic flexor gamma-motoneurones revealed by an injection of DOPA. Acta Physiol Scand. 1969 Sep-Oct;77(1):106–124. doi: 10.1111/j.1748-1716.1969.tb04557.x. [DOI] [PubMed] [Google Scholar]
  6. Burke D., Hagbarth K. E., Löfstedt L. Muscle spindle responses in man to changes in load during accurate position maintenance. J Physiol. 1978 Mar;276:159–164. doi: 10.1113/jphysiol.1978.sp012225. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Burke R. E., Tsairis P. Histochemical and physiological profile of a skeletofusimotor (beta) unit in cat soleus muscle. Brain Res. 1977 Jul 1;129(2):341–345. doi: 10.1016/0006-8993(77)90013-0. [DOI] [PubMed] [Google Scholar]
  8. Cody F. W., Harrison L. M., Taylor A. Analysis of activity of muscle spindles of the jaw-closing muscles during normal movements in the cat. J Physiol. 1975 Dec;253(2):565–582. doi: 10.1113/jphysiol.1975.sp011207. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Cody F. W., Lee R. W., Taylor A. A functional analysis of the components of the mesencephalic nucleus of the fifth nerve in the cat. J Physiol. 1972 Oct;226(1):249–261. doi: 10.1113/jphysiol.1972.sp009983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Corda M., von Euler C., Lennerstrand G. Reflex and cerebellar influences on alpha and on 'rhythmic' and 'tonic' gamma activity in the intercostal muscle. J Physiol. 1966 Jun;184(4):898–923. doi: 10.1113/jphysiol.1966.sp007956. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. EKLUND G., VON EULER, RUTKOWSKI S. SPONTANEOUS AND REFLEX ACTIVITY OF INTERCOSTAL GAMMA MOTONEURONES. J Physiol. 1964 May;171:139–163. doi: 10.1113/jphysiol.1964.sp007368. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Gladden M. H., McWilliam P. N. The activity of intrafusal muscle fibres in anaesthetized, decerebrate and spinal cats [proceedings]. J Physiol. 1977 Dec;273(2):49P–50P. [PubMed] [Google Scholar]
  13. Goodwin G. M., Luschei E. S. Discharge of spindle afferents from jaw-closing muscles during chewing in alert monkeys. J Neurophysiol. 1975 May;38(3):560–571. doi: 10.1152/jn.1975.38.3.560. [DOI] [PubMed] [Google Scholar]
  14. Grillner S. The influence of DOPA on the static and the dynamic fusimotor activity to the triceps surae of the spinal cat. Acta Physiol Scand. 1969 Dec;77(4):490–509. doi: 10.1111/j.1748-1716.1969.tb04592.x. [DOI] [PubMed] [Google Scholar]
  15. Hagbarth K. E., Vallbo A. B. Single unit recordings from muscle nerves in human subjects. Acta Physiol Scand. 1969 Jul;76(3):321–334. doi: 10.1111/j.1748-1716.1969.tb04475.x. [DOI] [PubMed] [Google Scholar]
  16. Hulliger M., Matthews P. B., Noth J. Effects of combining static and dynamic fusimotor stimulation on the response of the muscle spindle primary ending to sinusoidal stretching. J Physiol. 1977 Jun;267(3):839–856. doi: 10.1113/jphysiol.1977.sp011840. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Kirkwood P. A., Sears T. A. Monosynaptic excitation of motoneurones from muscle spindle secondary endings of intercostal and triceps surae muscles in the cat. J Physiol. 1975 Feb;245(2):64P–66P. [PubMed] [Google Scholar]
  18. Kirkwood P. A., Sears T. A. Spike triggered averaging for the measurement of single unit conduction velocities. J Physiol. 1975 Feb;245(2):58P–59P. [PubMed] [Google Scholar]
  19. Loeb G. E., Duysens J. Activity patterns in individual hindlimb primary and secondary muscle spindle afferents during normal movements in unrestrained cats. J Neurophysiol. 1979 Mar;42(2):420–440. doi: 10.1152/jn.1979.42.2.420. [DOI] [PubMed] [Google Scholar]
  20. Lund J. P., Richmond F. J., Touloumis C., Patry Y., Lamarre Y. The distribution of Golgi tendon organs and muscle spindles in masseter and temporalis muscles of the cat. Neuroscience. 1978;3(2):259–270. doi: 10.1016/0306-4522(78)90107-0. [DOI] [PubMed] [Google Scholar]
  21. Lund J. P., Smith A. M., Sessle B. J., Murakami T. Activity of trigeminal alpha- and gamma-motoneurons and muscle afferents during performance of a biting task. J Neurophysiol. 1979 May;42(3):710–725. doi: 10.1152/jn.1979.42.3.710. [DOI] [PubMed] [Google Scholar]
  22. Prochazka A., Stephens J. A., Wand P. Muscle spindle discharge in normal and obstructed movements. J Physiol. 1979 Feb;287:57–66. doi: 10.1113/jphysiol.1979.sp012645. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Prochazka A., Westerman R. A., Ziccone S. P. Ia afferent activity during a variety of voluntary movements in the cat. J Physiol. 1977 Jun;268(2):423–448. doi: 10.1113/jphysiol.1977.sp011864. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. SEARS T. A. EFFERENT DISCHARGES IN ALPHA AND FUSIMOTOR FIBRES OF INTERCOSTAL NERVES OF THE CAT. J Physiol. 1964 Nov;174:295–315. doi: 10.1113/jphysiol.1964.sp007488. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Sessle B. J. Identification of alpha and gamma trigeminal motoneurons and effects of stimulation of amygdala, cerebellum, and cerebral cortex. Exp Neurol. 1977 Feb;54(2):303–322. doi: 10.1016/0014-4886(77)90272-2. [DOI] [PubMed] [Google Scholar]
  26. Sjöström A., Zangger P. Muscle spindle control during locomotor movements generated by the deafferented spinal cord. Acta Physiol Scand. 1976 Jul;97(3):281–291. doi: 10.1111/j.1748-1716.1976.tb10265.x. [DOI] [PubMed] [Google Scholar]
  27. Taylor A. A technique for recording normal jaw movements in conscious cats. Med Biol Eng. 1969 Jan;7(1):89–90. doi: 10.1007/BF02474674. [DOI] [PubMed] [Google Scholar]
  28. Taylor A., Cody F. W. Jaw muscle spindle activity in the cat during normal movements of eating and drinking. Brain Res. 1974 May 17;71(2-3):523–530. doi: 10.1016/0006-8993(74)90996-2. [DOI] [PubMed] [Google Scholar]
  29. Taylor A., Davey M. R. Behaviour of jaw muscle stretch receptors during active and passive movements in the cat. Nature. 1968 Oct 19;220(5164):301–302. doi: 10.1038/220301a0. [DOI] [PubMed] [Google Scholar]
  30. Vallbo A. B. Human muscle spindle discharge during isometric voluntary contractions. Amplitude relations between spindle frequency and torque. Acta Physiol Scand. 1974 Feb;90(2):319–336. doi: 10.1111/j.1748-1716.1974.tb05594.x. [DOI] [PubMed] [Google Scholar]

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