OLIGOSYNAPTIC INHIBITION OF GROUP Ia AFFERENTS FROM BRACHIORADIALIS TO TRICEPS BRACHII MOTOR NEURONS IN HUMANS

作者：Sato Toshiaki; Nito Mitsuhiro; Suzuki Katsuhiko; Fujii Hiromi; Hashizume Wataru; Miyasaka Takuji; Shindo Masaomi; Naito Akira^*

来源：Muscle & Nerve, 2018, 57(1): 122-128.

DOI：10.1002/mus.25664

• brachioradialis
• group Ia afferents
• humans
• oligosynaptic inhibition
• triceps brachii

Introduction: 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.

• 出版日期2018-1