Recording an identified pyramidal volley evoked by transcranial magnetic stimulation in a conscious macaque monkey.
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.
Baker
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Department of Anatomy, Cambridge University, UK.
Olivier
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E
Lemon
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D000818:Animals; D004576:Electromyography; D004594:Electrophysiology; D005260:Female; D008252:Macaca fascicularis; D009044:Motor Cortex / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D010812:Physical Stimulation; D017966:Pyramidal Cells / Q000502:physiology; D011712:Pyramidal Tracts / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation