Skip to main content
PMC home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1968 Sep;198(1):145–166. doi: 10.1113/jphysiol.1968.sp008598

The distribution of monosynaptic excitation from the pyramidal tract and from primary spindle afferents to motoneurones of the baboon's hand and forearm

J F M Clough, D Kernell, C G Phillips
PMCID: PMC1365314  PMID: 16992310

Abstract

1. Intracellular records were obtained from motoneurones innervating muscles of the baboon's forearm and hand. Monosynaptic excitatory postsynaptic potentials (EPSPs) were elicited by stimulation of motor cortex (CM EPSPs) and peripheral nerves (Ia EPSPs).

2. CM EPSPs were larger on average in motoneurones innervating intrinsic hand muscles and extensor digitorum communis (EDC) than in neurones of other forearm muscles.

3. Among motoneurones of the median nerve, the CM EPSP tended to be larger for cells with more rapidly conducting axons than for those with more slowly conducting axons. Among motoneurones of EDC the opposite tendency was found.

4. The afferent fibres responsible for the Ia EPSP nearly always had a lower stimulus threshold than that of motor axons in the same nerve. Some observations were made concerning the distribution of heteronymous Ia EPSPs.

5. Among motoneurones of a given nerve, those with large Ia EPSPs tended to receive larger CM EPSPs than did cells in which the Ia EPSP was small.

6. The results are discussed in relation to problems concerning the pyramidal control of hand and finger movement.

Full text

PDF
145

Selected References

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

  1. ARAKI T., OTANI T. Response of single motoneurons to direct stimulation in toad's spinal cord. J Neurophysiol. 1955 Sep;18(5):472–485. doi: 10.1152/jn.1955.18.5.472. [DOI] [PubMed] [Google Scholar]
  2. Ashworth B., Grimby L., Kugelberg E. Comparison of voluntary and reflex activation of motor units. Functional organization of motor neurones. J Neurol Neurosurg Psychiatry. 1967 Apr;30(2):91–98. doi: 10.1136/jnnp.30.2.91. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. BROOKHART J. M. A study of corticospinal activation of motor neurons. Res Publ Assoc Res Nerv Ment Dis. 1952;30:157–173. [PubMed] [Google Scholar]
  4. Burke R. E. Firing patterns of gastrocnemius motor units in the decerebrate cat. J Physiol. 1968 Jun;196(3):631–654. doi: 10.1113/jphysiol.1968.sp008527. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. CORDA M., EKLUND G., VON EULER EXTERNAL INTERCOSTAL AND PHRENIC ALPHA-MOTOR RESPONSES TO CHANGES IN RESPIRATORY LOAD. Acta Physiol Scand. 1965 Mar;63:391–400. doi: 10.1111/j.1748-1716.1965.tb04079.x. [DOI] [PubMed] [Google Scholar]
  6. Clough J. F., Kernell D., Phillips C. G. Conduction velocity in proximal and distal portions of forelimb axons in the baboon. J Physiol. 1968 Sep;198(1):167–178. doi: 10.1113/jphysiol.1968.sp008599. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. ECCLES J. C., ECCLES R. M., LUNDBERG A. The action potentials of the alpha motoneurones supplying fast and slow muscles. J Physiol. 1958 Jul 14;142(2):275–291. doi: 10.1113/jphysiol.1958.sp006015. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. ECCLES J. C., ECCLES R. M., LUNDBERG A. The convergence of monosynaptic excitatory afferents on to many different species of alpha motoneurones. J Physiol. 1957 Jun 18;137(1):22–50. doi: 10.1113/jphysiol.1957.sp005794. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. ECCLES J. C., ECCLES R. M., SHEALY C. N. An investigation into the effect of degenerating primary afferent fibers on the monosynpatic innervation of motoneurons. J Neurophysiol. 1962 Jul;25:544–558. doi: 10.1152/jn.1962.25.4.544. [DOI] [PubMed] [Google Scholar]
  10. ECCLES R. M., LUNDBERG A. Integrative pattern of Ia synaptic actions on motoneurones of hip and knee muscles. J Physiol. 1958 Dec 4;144(2):271–298. doi: 10.1113/jphysiol.1958.sp006101. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. EVARTS E. V. RELATION OF DISCHARGE FREQUENCY TO CONDUCTION VELOCITY IN PYRAMIDAL TRACT NEURONS. J Neurophysiol. 1965 Mar;28:216–228. doi: 10.1152/jn.1965.28.2.216. [DOI] [PubMed] [Google Scholar]
  12. Eccles R. M., Phillips C. G., Chien-Ping W. Motor innervation, motor unit organization and afferent innervation of m. extensor digitorum communis of the baboon's forearm. J Physiol. 1968 Sep;198(1):179–192. doi: 10.1113/jphysiol.1968.sp008600. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Evarts E. V. Pyramidal tract activity associated with a conditioned hand movement in the monkey. J Neurophysiol. 1966 Nov;29(6):1011–1027. doi: 10.1152/jn.1966.29.6.1011. [DOI] [PubMed] [Google Scholar]
  14. GRANIT R., KAADA B. R. Influence of stimulation of central nervous structures on muscle spindles in cat. Acta Physiol Scand. 1952;27(2-3):130–160. doi: 10.1111/j.1748-1716.1953.tb00930.x. [DOI] [PubMed] [Google Scholar]
  15. GRANIT R., PHILLIPS C. G., SKOGLUND S., STEG G. Differentiation of tonic from phasic alpha ventral horn cells by stretch, pinna and crossed extensor reflexes. J Neurophysiol. 1957 Sep;20(5):470–481. doi: 10.1152/jn.1957.20.5.470. [DOI] [PubMed] [Google Scholar]
  16. HERN J. E., LANDGREN S., PHILLIPS C. G., PORTER R. Selective excitation of corticofugal neurones by surface-anodal stimulation of the baboon's motor cortex. J Physiol. 1962 Apr;161:73–90. doi: 10.1113/jphysiol.1962.sp006874. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. HERN J. E., PHILLIPS C. G., PORTER R. Electrical thresholds of unimpaled corticospinal cells in the cat. Q J Exp Physiol Cogn Med Sci. 1962 Apr;47:134–140. doi: 10.1113/expphysiol.1962.sp001584. [DOI] [PubMed] [Google Scholar]
  18. Hardin W. B., Jr Spontaneous activity in the pyramidal tract of chronic cats and monkeys; recorded with indwelling electrodes. Arch Neurol. 1965 Nov;13(5):501–512. doi: 10.1001/archneur.1965.00470050049006. [DOI] [PubMed] [Google Scholar]
  19. Henneman E., Somjen G., Carpenter D. O. Excitability and inhibitability of motoneurons of different sizes. J Neurophysiol. 1965 May;28(3):599–620. doi: 10.1152/jn.1965.28.3.599. [DOI] [PubMed] [Google Scholar]
  20. Kernell D., Chien-Ping W. U. Responses of the pyramidal tract to stimulation of the baboon's motor cortex. J Physiol. 1967 Aug;191(3):653–672. doi: 10.1113/jphysiol.1967.sp008273. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Kernell D., Chien-Ping W. Post-synaptic effects of cortical stimulation on forelimb motoneurones in the baboon. J Physiol. 1967 Aug;191(3):673–690. doi: 10.1113/jphysiol.1967.sp008274. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Kernell D. Input resistance, electrical excitability, and size of ventral horn cells in cat spinal cord. Science. 1966 Jun 17;152(3729):1637–1640. doi: 10.1126/science.152.3729.1637. [DOI] [PubMed] [Google Scholar]
  23. Koeze T. H., Phillips C. G., Sheridan J. D. Thresholds of cortical activation of muslce spindles and alpha motoneurones of the baboon's hand. J Physiol. 1968 Mar;195(2):419–449. doi: 10.1113/jphysiol.1968.sp008466. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. LANDGREN S., PHILLIPS C. G., PORTER R. Minimal synaptic actions of pyramidal impulses on some alpha motoneurones of the baboon's hand and forearm. J Physiol. 1962 Apr;161:91–111. doi: 10.1113/jphysiol.1962.sp006875. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. LAWRENCE D. G., KUYPERS H. G. PYRAMIDAL AND NON-PYRAMIDAL PATHWAYS IN MONKEYS: ANATOMICAL AND FUNCTIONAL CORRELATION. Science. 1965 May 14;148(3672):973–975. doi: 10.1126/science.148.3672.973. [DOI] [PubMed] [Google Scholar]
  26. LONG C., BROWN M. E. ELECTROMYOGRAPHIC KINESIOLOGY OF THE HAND: MUSCLES MOVING THE LONG FINGER. J Bone Joint Surg Am. 1964 Dec;46:1683–1706. [PubMed] [Google Scholar]
  27. LUNDBERG A., VOORHOEVE P. Effects from the pyramidal tract on spinal reflex arcs. Acta Physiol Scand. 1962 Nov-Dec;56:201–219. doi: 10.1111/j.1748-1716.1962.tb02498.x. [DOI] [PubMed] [Google Scholar]
  28. MATTHEWS P. B. MUSCLE SPINDLES AND THEIR MOTOR CONTROL. Physiol Rev. 1964 Apr;44:219–288. doi: 10.1152/physrev.1964.44.2.219. [DOI] [PubMed] [Google Scholar]
  29. PHILLIPS C. G., PORTER R. THE PYRAMIDAL PROJECTION TO MOTONEURONES OF SOME MUSCLE GROUPS OF THE BABOON'S FORELIMB. Prog Brain Res. 1964;12:222–245. doi: 10.1016/s0079-6123(08)60625-1. [DOI] [PubMed] [Google Scholar]
  30. PRESTON J. B., WHITLOCK D. G. A comparison of motor cortex effects on slow and fast muscle innervations in the monkey. Exp Neurol. 1963 Apr;7:327–341. doi: 10.1016/0014-4886(63)90079-7. [DOI] [PubMed] [Google Scholar]
  31. PRESTON J. B., WHITLOCK D. G. Intracellular potentials recorded from motoneurons following precentral gyrus stimulation in primate. J Neurophysiol. 1961 Jan;24:91–100. doi: 10.1152/jn.1961.24.1.91. [DOI] [PubMed] [Google Scholar]
  32. PRESTON J. B., WHITLOCK D. G. Precentral facilitation and inhibition of spinal motoneurons. J Neurophysiol. 1960 Mar;23:154–170. doi: 10.1152/jn.1960.23.2.154. [DOI] [PubMed] [Google Scholar]
  33. SASAKI K., TANAKA T. PHASIC AND TONIC INNERVATION OF SPINAL ALPHA MOTONEURONS FROM UPPER BRAIN CENTERS. Jpn J Physiol. 1964 Feb 15;14:56–66. doi: 10.2170/jjphysiol.14.56. [DOI] [PubMed] [Google Scholar]
  34. Sherrington C. S. Flexion-reflex of the limb, crossed extension-reflex, and reflex stepping and standing. J Physiol. 1910 Apr 26;40(1-2):28–121. doi: 10.1113/jphysiol.1910.sp001362. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. UEMURA K., PRESTON J. B. COMPARISON OF MOTOR CORTEX INFLUENCES UPON VARIOUS HIND-LIMB MOTONEURONS IN PYRAMIDAL CATS AND PRIMATES. J Neurophysiol. 1965 Mar;28:398–412. doi: 10.1152/jn.1965.28.2.398. [DOI] [PubMed] [Google Scholar]
  36. Willis W. D., Tate G. W., Ashworth R. D., Willis J. C. Monosynaptic excitation of motoneurons of individual forelimb muscles. J Neurophysiol. 1966 May;29(3):410–424. doi: 10.1152/jn.1966.29.3.410. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES