Recording an identified pyramidal volley evoked by transcranial magnetic stimulation in a conscious macaque monkey

Exp Brain Res. 1994;99(3):529-32. doi: 10.1007/BF00228989.


A descending volley in response to non-invasive transcranial magnetic stimulation has been recorded from the pyramidal tract in a conscious monkey and identified by means of a collision test. The short latency of the earliest wave was inconsistent with a trans-synaptically mediated activation of pyramidal tract neurones. Considerable variability in the size of this wave was seen in response to a constant stimulus, and isoflurane anaesthetic was shown to depress it markedly. These results are consistent with direct activation of pyramidal tract neurones at a site close to the cell body.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Electromyography
  • Electrophysiology
  • Female
  • Macaca fascicularis
  • Motor Cortex / physiology
  • Muscle, Skeletal / physiology
  • Physical Stimulation
  • Pyramidal Cells / physiology
  • Pyramidal Tracts / physiology*
  • Transcranial Magnetic Stimulation*