Elsevier

Progress in Neurobiology

Volume 48, Issues 4–5, March–April 1996, Pages 489-517
Progress in Neurobiology

Transmission of the cortical command for human voluntary movement through cervical propriospinal premotoneurons

https://doi.org/10.1016/0301-0082(96)00002-0Get rights and content

Abstract

In man there is now strong evidence for the existence of a system of cervical propriospinal premotoneurons interposed in the corticospinal pathway to upper limb motoneurons. The relevant neurons are located rostral to upper limb motoneurons. They receive both weak excitation and strong inhibition from low threshold afferents in the upper limb. Ongoing EMG activity recorded in wrist and elbow extensors during voluntary movements of different types (tonic contraction, reaching) is suppressed by a cutaneous volley evoked by stimulation of the superficial radial nerve. There is evidence that this cutaneous-induced suppression is due to inhibition of transmission of the cortical command in the system of cervical propriospinal premotoneurons, thus indicating that part of the descending command for movement reaches the relevant motoneurons via these premotoneurons. In patients with hemiplegia, the cutaneous-induced depression of ongoing EMG activity is significantly larger on the hemiplegic side. This suggests that the mechanisms underlying residual motricity after a lesion of the corticospinal tract involve the system of propriospinal premotoneurons.

References (61)

  • B. Alstermark et al.

    Integration in descending motor pathways controlling the forelimb in the cat. 9. Differential behavioural defects after spinal cord lesions interrupting defined pathways from higher centres to motoneurons

    Expl. Brain Res.

    (1981)
  • B. Alstermark et al.

    Integration in descending motor pathways controlling the forelimb in the cat. 10. Inhibitory pathways to forelimb motoneurons via C3–C4 propriospinal neurons

    Expl Brain Res.

    (1984)
  • B. Alstermark et al.

    Integration in descending motor pathways controlling the forelimb in the cat. 11. Inhibitory pathways from higher motor centres and forelimb afferents to C3–C4 propriospinal neurons

    Expl Brain Res.

    (1984)
  • F. Baldissera et al.

    Integration in spinal neuronal systems

  • P. Bawa et al.

    Recruitment of motor units in response to transcranial magnetic stimulation in man

    J. Physiol. (London)

    (1993)
  • A. Berardelli et al.

    Evidence favouring presynaptic inhibition between antagonist muscle afferents in the human forearm

    J. Physiol. (London)

    (1987)
  • D. Burke et al.

    Convergence of descending and various peripheral inputs onto common propriospinal-like neurons in man

    J. Physiol. (London)

    (1992)
  • D. Burke et al.

    Non monosynaptic transmission of the cortical command for voluntary movement in man

    J. Physiol. (London)

    (1994)
  • D. Burke et al.

    Changes in presynaptic inhibition of afferents to propriospinal-like neurons in man during voluntary contractions

    J. Physiol. (London)

    (1992)
  • D. Burke et al.

    Cutaneous afferent activity in median and radial nerve fascicles: a microelectrode study

    J. Neurol. Neurosurg. Psychiat.

    (1975)
  • P. Cavallari et al.

    Pattern of projections of group I afferents from elbow muscles to motoneurons supplying wrist muscles in man

    Expl Brain Res.

    (1992)
  • J.M.A. Cowan et al.

    The effect of percutaneous motor cortex stimulation on H reflexes in muscles of the arm and leg in intact man

    J. Physiol. (London)

    (1986)
  • C. Crone et al.

    Sensitivity of monosynaptic test reflexes to facilitation and inhibition as a function of the test reflex size: a study in man and the cat

    Expl Brain Res.

    (1990)
  • B.L. Day et al.

    Electric and magnetic stimulation of human motor cortex: surface EMG and single motor unit responses

    J. Physiol. (London)

    (1989)
  • J.C. Eccles

    The Physiology of Synapses

  • R.M. Eccles et al.

    Spatial facilitation in the direct inhibitory pathways

    Nature

    (1957)
  • E.E. Fetz et al.

    Relation between shapes of post-synaptic potentials and changes in firing probability of cat motoneurons

    J. Physiol. (London)

    (1983)
  • E. Fournier et al.

    Evidence for interneuronally mediated Ia excitatory effects to human quadriceps motoneurons

    J. Physiol. (London)

    (1986)
  • E. Fournier et al.

    Changes in transmission in some reflex pathways during movement in humans

    News Physiol. Sci.

    (1989)
  • J.M. Gracies et al.

    Evidence for corticospinal excitation of presumed propriospinal neurons in man

    J. Physiol. (London)

    (1994)
  • Cited by (0)

    View full text