Cavallari P, Katz R, Penicaud A
Département de Rééducation, Hôpital de la Salpêtrière, Paris, France.
Exp Brain Res. 1992;91(2):311-9. doi: 10.1007/BF00231664.
The pattern of projections of low threshold afferents from triceps and biceps brachii muscles onto motoneurones innervating muscles acting at the wrist was assessed by a reflex and a poststimulus time histogram (psth) technique. Activation of low-threshold afferents originating from elbow flexors or extensors resulted in an early, short-lasting inhibition of wrist flexor motoneurones (flexor carpi radialis, flexor carpi ulnaris). An inhibition was also found in the extensor carpi radialis (ECR) motoneurones after stimulation of low-threshold afferents from triceps. Evidence is presented that Ia fibres contribute to these effects. The inhibitory effects were found in all subjects, but they were constant in only 57% of the reflex experimental sessions and in 25% of the explored motor units. Stimulation of biceps low-threshold afferents was always ineffective on ECR motoneurones. No early facilitation was ever seen in motor nuclei innervating wrist muscles following stimulation of low threshold afferents from biceps and triceps. The pattern of transjoint projections of group I afferents from proximal to distal muscles and from distal to proximal ones (Cavallari and Katz 1989) is discussed in relation to that described in the cat forelimb.
采用反射和刺激后时间直方图（PSTH）技术，评估了肱三头肌和肱二头肌低阈值传入纤维向支配腕部运动的运动神经元的投射模式。源于肘部屈肌或伸肌的低阈值传入纤维的激活，导致腕部屈肌运动神经元（桡侧腕屈肌、尺侧腕屈肌）出现早期、短暂的抑制。刺激肱三头肌的低阈值传入纤维后，桡侧腕伸肌（ECR）运动神经元也出现抑制。有证据表明Ia纤维参与了这些效应。所有受试者均出现抑制效应，但仅57%的反射实验和25%的被探索运动单位中，抑制效应是持续的。刺激肱二头肌低阈值传入纤维对ECR运动神经元始终无效。刺激肱二头肌和肱三头肌的低阈值传入纤维后，在支配腕部肌肉的运动核中从未观察到早期易化现象。本文结合猫前肢的相关描述，讨论了I组传入纤维从近端到远端肌肉以及从远端到近端肌肉的跨关节投射模式（Cavallari和Katz，1989）。
