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Oligosynaptic inhibition of group Ia afferents from brachioradialis to triceps brachii motor neurons in humans
Author(s) -
Sato Toshiaki,
Nito Mitsuhiro,
Suzuki Katsuhiko,
Fujii Hiromi,
Hashizume Wataru,
Miyasaka Takuji,
Shindo Masaomi,
Naito Akira
Publication year - 2018
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.25664
Subject(s) - brachioradialis , stimulation , medicine , tonic (physiology) , stimulus (psychology) , electromyography , neuroscience , anesthesia , anatomy , physical medicine and rehabilitation , psychology , psychotherapist
: This study examines effects of low‐threshold afferents from the brachioradialis (BR) on excitability of triceps brachii (TB) motor neurons in humans. Methods : We evaluated the effects using a post stimulus time histogram (PSTH) and electromyogram averaging (EMG‐A) methods in 13 healthy human participants. Electrical conditioning stimulation to the radial nerve branch innervating BR with the intensity below the motor threshold was delivered. Results : In the PSTH study, the stimulation produced a trough (inhibition) in 36/69 TB motor units for all the participants. A cutaneous stimulation never provoked such inhibition. The central latency of the inhibition was 1.5 ± 0.5 ms longer than that of the homonymous facilitation. In the EMG‐A study, the stimulation produced inhibition in EMG‐A of TB in all participants. The inhibition diminished with a tonic vibration stimulation to BR. Discussion : These findings suggest that oligosynaptic inhibition mediated by group Ia afferents from BR to TB exists in humans. Muscle Nerve 57 : 122–128, 2018