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Activation of the human diaphragm from the motor cortex.
Author(s) -
Gandevia S C,
Rothwell J C
Publication year - 1987
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1987.sp016445
Subject(s) - phrenic nerve , motor cortex , stimulation , medicine , spinal cord , anatomy , electromyography , diaphragm (acoustics) , stimulus (psychology) , anesthesia , neuroscience , respiratory system , biology , psychology , physical medicine and rehabilitation , physics , psychiatry , acoustics , loudspeaker , psychotherapist
1. Rapidly conducting corticofugal pathways were activated by percutaneous electrical stimulation of the motor cortex in normal subjects. The electromyographic response produced in the diaphragm was assessed with recordings via a gastro‐oesophageal catheter and the mechanical response was measured as a change in transdiaphragmatic pressure. 2. The mean latency from the cortical stimulus to the muscle action potential in the diaphragm was 12.3 ms. The latency to the diaphragm from stimulation of the cervical spinal cord at the C4 level was 8.0 ms. The mean 'central conduction time' to the phrenic motor nucleus of 4.3 ms (range 4.0‐4.6 ms) was similar to that for the deltoid (mean 4.4 ms; range 4.0‐4.8 ms) recorded in the same subjects. 3. The largest twitch contractions of the diaphragm were evoked by cortical stimuli near the vertex during inspiration. The amplitude and duration of the electromyographic and mechanical responses often exceeded those produced by a supramaximal stimulus to both phrenic nerves simultaneously. 4. These results provide the first direct evidence that there is a rapidly conducting oligosynaptic pathway from the motor cortex to the human diaphragm.