Abstract
SINCE Lloyd's original work on the myotatic unit more than 30 yr ago1, it has been assumed that the monosynaptic excitation of motoneurones from receptor nerve fibres derives entirely from the Group Ia afferents, which terminate as primary endings in the muscle spindles. Group Ib afferents from tendon organs are thought to exert their inhibitory actions2 over di- or trisynaptic pathways3, while Group II and III fibres, which include those from the secondary endings of muscle spindles, form part of the flexor reflex afferent (FRA) system4, the synaptic actions of which are thought also to be mediated polysynaptically5. Whereas the monosynaptic excitation of motoneurones by Group Ia fibres has been directly confirmed in terms of unitary synaptic potentials evoked by single, stretch excited primary endings6, knowledge of the synaptic actions of fibres innervating secondary endings is known only indirectly from electrical stimulation of Group II fibres and is not without controversy7.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Lloyd, D. P. C., J. Neurophysiol., 6, 293–315 (1943).
Laporte, Y., and Lloyd, D. P. C., Am. J. Physiol., 169, 609–621 (1952).
Eccles, J. C., Eccles, R. M., and Lundberg, A., J. Physiol., Lond., 138, 227–252 (1957).
Holmqvist, B., and Lundberg, A., Acta physiol. Scand., 54, supplement 186, 51 (1961).
Eccles, R. M., and Lundberg, A., Archs Ital. Biol., 97, 199–221 (1959).
Mendell, L. M., and Henneman, E., J. Neurophysiol., 34, 171–187 (1971).
Matthews, P. B. C., Mammalian Muscle Receptors and their Central Actions (Edward Arnold, London, 1972).
Sears, T. A. J. Physiol., Lond., 175, 386–403 (1964).
Sears, T. A., and Stagg, D., J. Physiol., Lond., 191, 108–109P (1967).
Kirkwood, P. A., and Sears, T. A., J. Physiol., Lond., 234, 87–89P (1973).
Andersson, B. F., Lennerstrand, G., and Thoden, U., Acta physiol. Scand., 74, 301–318 (1968).
Fu, T. C., and Schomburg, E. D., Acta physiol. Scand., 91, 314–329 (1974).
Cooper, S., Q. Jl exp. Physiol., 46, 389–398 (1961).
Matthews, P. B. C., and Stein, R. B., J. Physiol., Lond., 202, 59–82 (1969).
Sears, T. A., in New Developments in Electromyography and Clinical Neurophysiology, 3, (edit. by Desmedt, J. E.), 144–155 (Karger, Basel, 1972).
Newsom Davis, J., and Sears, T. A., J. Physiol., Lond., 209, 711–738 (1970).
Hammond, P. H., in Proc. 3rd Int. Conf. Med. Electron., 190–199 (London, Institution of Electrical Engineers, 1960).
Marsden, C. D., Merton, P. A., and Morton, H. B., Nature, 238, 140–143 (1972).
Matthews, P. B. C., J. Physiol., Lond., 204, 365–393 (1969).
McGrath, G. J., and Matthews, P. B. C., J. Physiol., Lond., 235, 371–408 (1973).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
KIRKWOOD, P., SEARS, T. Monosynaptic excitation of motoneurones from secondary endings of muscle spindles. Nature 252, 243–244 (1974). https://doi.org/10.1038/252243a0
Received:
Issue Date:
DOI: https://doi.org/10.1038/252243a0
This article is cited by
-
Spinal Cord Circuits: Models and Reality
Neurophysiology (2021)
-
Glutamate and AMPA receptor immunoreactivity in Ia synapses with motoneurons and neurons of the central cervical nucleus
Experimental Brain Research (2003)
-
An intact peripheral nerve preparation for monitoring inputs from single muscle afferent fibres
Experimental Brain Research (1997)
-
Spinal reflex pattern in the tortoise (Testudo graeca, T. hermanni)
Journal of Comparative Physiology A (1985)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
