Inhibitory projections from the biceps brachii to the pronator teres motoneurons in the human.

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• 作者：Miyasaka ; Takuji ; Ying-Jie ; Sun ; Naito ; Akira ; Shindo ; Masaomi
• 刊名：Neuroscience Research
• 出版年：1996
• 出版时间：1996
• 年：1996
• 卷：25
• 期：Supplement 2
• 页码：S183
• 全文大小：67.9 K

文摘

Projections of low threshold afferents from the biceps brachii (BB) to the pronator teres (PT) motoneurons were studied in four healthy human volunteers using a “triggered” post-stimulus time histogram technique on voluntarily-activated motor units. For conditioning stimuli, electrical rectangular pulses with 0.4 ms duration were delivered to the musculocutaneous branch innervating the BB with surface electrodes. Needle electrodes were used for recording single motor unit discharges from the PT. In 26 out of 52 units (50 % ), early (14-35 ms of latency) and significant troughs (p<0.05) were induced with the stimulus intensity of less than 1.0 × MT (motor threshold). The central latency of the trough was less than 1 ms longer than that of the monosynaptic peak induced by the homonymous nerve stimulation. No significant troughs or peaks were provoked by pure cutaneous stimulation. These findings suggest that motoneurons of the PT receive inhibitory projections of group I afferents from the BB through an oligo(di or tri)-synaptic linkage in the spinal cord.