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Origin of far‐field potentials in the ulnar compound muscle action potential
Author(s) -
Sonoo Masahiro,
Kurokawa Katsumi,
Higashihara Mana,
Kurono Hiroko,
Hokkoku Keiichi,
Hatanaka Yuki,
Shimizu Teruo
Publication year - 2011
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/mus.21931
Subject(s) - ulnar nerve , compound muscle action potential , anatomy , dorsum , hand muscles , motor unit , electromyography , medicine , electrophysiology , neuroscience , physical medicine and rehabilitation , psychology , elbow
The compound muscle action potential (CMAP) following ulnar nerve stimulation receives a considerable contribution from far‐field potentials (FFPs), although their origin is not entirely clear. We investigated this issue using voluntary contractions. Methods: In 7 control subjects, we placed multiple recording electrodes over the motor points of ulnar‐innervated muscles. We asked the subjects to perform a weak movement corresponding to the action of each muscle, and identified the single motor unit potentials (MUPs) from that muscle. We summed the MUPs from each individual muscle and reconstructed the CMAPs. Results: The reconstructed CMAPs coincided well with the actual ones. The N1, P1, and early N2 components of the FFPs were generated primarily by palmar, but also by dorsal, interosseous muscles. The abductor digiti minimi muscle usually generated positive–negative biphasic FFPs, and the negative FFP generated the late N2 component. Conclusions: These results should prompt a revision of the theory of FFP generation. Muscle Nerve, 2011