Summary
This paper describes the results of recordings from fusimotor and alphamotor axons of the cat masseter nerve and from muscle spindle afferents from the jaw closing muscles. Criteria are described for recognising fusimotor from alpha motor axons and their behaviour is examined during cyclic reflex jaw movements under light anaesthesia. Approximately one third of the fusimotor fibres showed an increased and ‘sustained’ discharge during a movement sequence. The rest showed strong modulation with maximum frequency during the muscle shortening phase and were referred to as ‘modulated’. By recording from primary and secondary spindle afferents during separate but very similar experiments it was deduced that the ‘sustained’ type of response was probably in dynamic fusimotor fibres and the ‘modulated’ type in static fusimotor fibres. New observations of jaw muscle spindle afferent discharge in freely moving alert cats indicated that the same sort of modulated static fusimotor drive may accompany masticatory movements but that this does not normally overcome the unloading effect of unobstructed shortening. Sometimes, when extra loading slows shortening, a considerable enhancement of spindle afferent firing is seen which could have a significant load compensating effect.
A general proposal is made that one control strategy which can be used is to set the dynamic fusimotor drive to give appropriate incremental sensitivity to stretch and to vary static fusimotor drive as a ‘temporal template’ of the intended movement.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Appelberg, B., Jeneskog, T. and Johansson, H. (1975). Rubrospinal control of static and dynamic fusimotor neurons, Acta physiol. scand., 95, 431–440
Appenteng, K., Morimoto, T. and Taylor, A. (1980). Fusimotor activity in masseter nerve of the cat during reflex jaw movements, J. Physiol., Lond., to be published
Cody, F. W. J., Harrison, L. M. and Taylor, A. (1975). Analysis of activity of muscle spindles of the jaw closing muscles during normal movements in the cat, J. Physiol., Lond., 253, 565–582
Cody, F. W. J., Lee, R. W. H. and Taylor, A. (1972). A functional analysis of the components of the mesencephalic nucleus of the fifth nerve in the cat, J. Physiol., Lond., 226, 249–261
Critchlow, V. and von Euler, C. (1963). Intercostal muscle spindle activity and its γ motor control, J. Physiol., Lond., 168, 820–847
Cussons, T. D., Hulliger, M. and Matthews, P. B. C. (1977). Effects of fusimotor stimulation on the response of the secondary ending of the muscle spindle to sinusoidal stretching, J. Physiol., Lond., 270, 835–850
Dellow, P. G. and Lund, J. P. (1971). Evidence for central timing of rhythmical mastication, J. Physiol., Lond., 215, 1–13
Eccles, J. C., Eccles, R. M., Iggo, A. and Lundberg, A. (1960). Electrophysiological studies on γ-motoneurones, Acta physiol. scand., 50, 32–40
Eklund, G., von Euler, C. and Rutkowski, S. (1964). Spontaneous and reflex activity of intercostal gamma motoneurones, J. Physiol., Lond., 171, 139–163
von Euler, C. and Peretti, G. (1966). Dynamic and static contributions to the rhythmic γ activation of primary and secondary spindle endings in external intercostal muscle, J. Physiol., Lond., 187, 501–516
Goodwin, G. M. and Luschei, E. S. (1975). Discharge of spindle afferents from jaw-closing muscles during chewing in alert monkeys, J. Neurophysiol., 38, 560–571
Granit, R. (1955). Receptors and Sensory Perception, New Haven, Yale University Press
Lennerstrand, G. and Thoden, U. (1968). Muscle spindle responses to concomitant variations in length and in fusimotor activation, Acta physiol. scand., 74, 153–165
Loeb, G. E. and Duysens, G. (1979). Activity patterns in individual hind-limb primary and secondary muscle spindle afferents during normal movement in unrestrained cats, J. Neurophysiol., 42, 420–440
Matthews, P. B. C. (1962). The differentiation of two types of fusimotor fibre by their effects on the dynamic response of muscle spindle primary endings, Q. Jl exp. Physiol., 47, 324–333
Matthews, P. B. C. (1964). Muscle spindles and their motor control, Physiol. Rev., 44, 219–288
Matthews, P. B. C. (1972). Mammalian Muscle Receptors and Their Central Actions, London, Arnold
Merton, P. A. (1953). Speculations on the servo-control of movement. In The Spinal Cord (ed. G. E. W. Wolstenholme), London, Churchill, 247–255
Prochazka, A., Stephens, J. A. and Wand, P. (1979). Muscle spindle discharge in normal and obstructed movements, J. Physiol., Lond., 287, 57–66
Prochazka, A., Westerman, R. A. and Ziccone, S. P. (1976). Discharges of single hind limb afferents in the freely moving cat, J. Neurophysiol., 39, 1090–1104
Prochazka, A., Westerman, R. A. and Ziccone, S. P. (1977). Ia afferent activity during a variety of voluntary movements in the cat, J. Physiol., Lond., 268, 423–448
Proske, U. and Lewis, D. M. (1972). The effects of muscle stretch and vibration on fusimotor activity in the lightly anaesthetised cat, Brain Res., 46, 55–69
Sears, T. A. (1964). Efferent discharges in alpha and fusimotor fibres of intercostal nerves of the cat, J. Physiol., Lond., 174, 295–315
Sears, T. A. (1973). Servo control of the intercostal muscles. In New Developments in Electromyography and Clinical Neurophysiology (ed. J. Desmedt), Vol. 3, Karger, Basel, 404–417
Taylor, A. (1969). A technique for recording normal jaw movements in conscious cats, Med. Biol. Eng., 7, 89–90
Taylor, A. (1972). Muscle receptors in the control of voluntary movement, Paraplegia, 9, 167–172
Taylor, A., Appenteng, K. and Morimoto, T. (1980). Proprioceptive input from the jaw muscles and its influence on lapping, chewing and posture, Can. J. Physiol., Pharmacol., to be published.
Taylor, A. and Cody, F. W. J. (1974). Jaw muscle spindle activity in the cat during normal movements of eating and drinking, Brain Res., 71, 523–530
Trott, J. R. (1976). The effect of low amplitude muscle vibration on the discharge of fusimotor neurones in the decerebrate cat, J. Physiol., Lond., 255, 635–649
Vallbo, Å. B., Hagbarth, K.-E., Torebjörk, H. E. and Wallin, B. G. (1979). Somatosensory, proprioceptive and sympathetic activity in human peripheral nerves, Physiol. Rev., 59, 919–957
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Copyright information
© 1981 The contributors
About this chapter
Cite this chapter
Taylor, A., Appenteng, K. (1981). Distinctive modes of static and dynamic fusimotor drive in jaw muscles. In: Taylor, A., Prochazka, A. (eds) Muscle Receptors and Movement. Palgrave Macmillan, London. https://doi.org/10.1007/978-1-349-06022-1_18
Download citation
DOI: https://doi.org/10.1007/978-1-349-06022-1_18
Publisher Name: Palgrave Macmillan, London
Print ISBN: 978-1-349-06024-5
Online ISBN: 978-1-349-06022-1
eBook Packages: Biomedical and Life SciencesBiomedical and Life Sciences (R0)