Inhibitory pathways from Golgi tendon organs project widely between muscles crossing different joints and axes of rotation. Evidence suggests that the strength and distribution of this intermuscular inhibition is dependent on motor task and corresponding signals from the brainstem. The purpose of the present study was to investigate whether this sensory network is altered after spinal cord hemisection as a potential explanation for motor deficits observed after spinal cord injury (SCI). Force feedback was assessed between the long toe flexor and ankle plantarflexor (flexor hallucis longus), and the three major ankle extensors, (combined gastrocnemius, soleus, and plantaris muscles) in the hind limbs of unanesthetized, decerebrate, female cats. Data were collected from animals with intact spinal cords (control) and lateral spinal hemisections (LSHs) including chronic LSH (4–20 weeks), subchronic LSH (2 weeks), and acute LSH. Muscles were stretched individually and in pairwise combinations to measure intermuscular feedback between the toe flexor and each of the ankle extensors. In control animals, three patterns were observed (balanced inhibition between toe flexor and ankle extensors, stronger inhibition from toe flexor to ankle extensor, and vice versa). Following spinal hemisection, only strong inhibition from toe flexors onto ankle extensors was observed independent of survival time. The results suggest immediate and permanent reorganization of force feedback in the injured spinal cord. The altered strength and distribution of force feedback after SCI may be an important future target for rehabilitation.

中文翻译：

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脊髓损伤后长脚趾屈肌和主要踝伸肌之间抑制力反馈的重新分布。

来自高尔基腱器官的抑制通路在穿过不同关节和旋转轴的肌肉之间广泛投射。有证据表明，这种肌肉间抑制的强度和分布取决于运动任务和来自脑干的相应信号。本研究的目的是调查这种感觉网络在脊髓半切后是否发生改变，作为脊髓损伤 (SCI) 后观察到的运动缺陷的潜在解释。在未麻醉、去大脑的雌性猫的后肢中，评估了长脚趾屈肌和踝跖屈肌（拇长屈肌）以及三个主要的踝关节伸肌（联合腓肠肌、比目鱼肌和跖肌）之间的力反馈。从具有完整脊髓（对照）和脊髓侧半切（LSH）的动物收集数据，包括慢性 LSH（4-20 周）、亚慢性 LSH（2 周）和急性 LSH。肌肉被单独和成对组合拉伸，以测量脚趾屈肌和每个脚踝伸肌之间的肌间反馈。在对照动物中，观察到三种模式（脚趾屈肌和踝伸肌之间的平衡抑制，脚趾屈肌对踝伸肌的更强抑制，反之亦然）。脊髓半切后，仅观察到脚趾屈肌对踝伸肌的强烈抑制，与生存时间无关。结果表明受伤脊髓中的力反馈立即和永久重组。