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A Cervical Propriospinal System in Man

  • Emmanuel Pierrot-Deseilligny
  • Véronique Marchand-Pauvert
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Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 508)

Abstract

Peripheral stimuli facilitate, at a pre-motoneuronal level, the responses elicited in human upper limb motoneurons (MNs) by transcranial magnetic stimulation over the motor cortex (TMS). Several features indicate that the ‘relevant premotoneurones are distinct from segmental interneurones and located rostra] to MNs. Thus, corticospinal volleys would have an indirect (propriospinal) pathway to upper limb MNs, in addition to the direct cortico-motoneuronal pathway. Slightly increasing the corticospinal input causes the facilitation to be reversed to inhibition. This is consistent with a well-developed system of inhibitory intemeurones activated by corticospinal and afferent inputs inhibiting propriospinal neurones (PNs). Corticospinal activation of these inhibitory intemeurones would explain why propriospinally-mediated corticospinal EPSPs are weak in primate MNs after artificial (electrical or magnetic) activation of the corticospinal system by itself. However, indirect evidence for descending facilitation of PNs can be provided during normal voluntary contractions, while using the modulation of the ongoing EMG or of the H reflex.

Keywords

Transcranial Magnetic Stimulation Flexor Digitorum Superficialis Transcranial Magnetic Stimulation Intensity Combine Stimulation Separate Stimulus 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 2002

Authors and Affiliations

  • Emmanuel Pierrot-Deseilligny
  • Véronique Marchand-Pauvert
    • 1
  1. 1.Neurophysiologie CliniqueRééducation, La SalpêtriéreParis, Cedex 13France

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