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Magnetic stimulation excites skeletal muscle via motor nerve axons in the cat
Author(s) -
Ellaway Peter H.,
Rawlinson Steve R.,
Lewis Helen S.,
Davey Nick J.,
Maskill David W.
Publication year - 1997
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(199709)20:9<1108::aid-mus3>3.0.co;2-c
Subject(s) - stimulation , triceps surae muscle , skeletal muscle , sciatic nerve , anatomy , muscle contraction , neuromuscular junction , contraction (grammar) , motor nerve , medicine , isometric exercise , stimulus (psychology) , neuroscience , biology , psychology , psychotherapist
Surface magnetic stimulation has been applied directly over skeletal muscle (triceps surae) in decerebrated cats. Recordings were made of the twitch contraction and electromyographic responses in triceps surae, and of the centripetal nerve volley in the sciatic nerve or spinal roots. Stimulus/response curves were established up to the maximum output of the magnetic stimulator. Neuromuscular blockade abolished the twitch contraction and muscle action potential leaving the nerve volley unaffected. Raising the stimulator output to its maximum increased the size of the nerve volley but failed to produce any muscle response. We conclude that magnetic stimulation applied directly to skeletal muscle excites via stimulation of motor nerve axons. The maximum output of the stimulator was incapable of exciting muscle fibers by direct depolarization. Use of magnetic stimulation in the clinical appraisal of muscle function should be interpreted in the knowledge that the stimulator elicits contraction only indirectly through nerve stimulation. © 1997 John Wiley & Sons, Inc. Muscle Nerve 20: 1108–1114, 1997