Rossi A, Mazzocchio R, Scarpini C
Institute of Neurological Sciences, University of Siena, Italy.
Exp Neurol. 1987 Oct;98(1):1-12. doi: 10.1016/0014-4886(87)90066-5.
The influence of static head-body tilts in the sagittal plane on the activity of Renshaw cells coupled to the soleus extensor alpha-motoneurons was studied in eight human subjects. Head-body rotation was carried out using a tilting seat and its effect was evaluated at 80 degrees (normal sitting position) and at 40 degrees of backward inclination (nose-up). Renshaw cell activity was assessed through a specially designed method of paired H-reflexes first described by Bussel and Pierrot-Deseilligny. alpha-Motoneuron excitability was also independently studied by mapping a reference H-reflex amplitude as a function of static head-body displacements. In almost all subjects Renshaw cell activity was increased at 40 degrees backward inclination with respect to control values at 80 degrees. These changes were attributed to the tonic labyrinthine reflexes capable of decoupling Renshaw cell activity from their motoneurons when the body was tilted backward from the upright position. We discuss the hypothetical functional modalities of the recurrent inhibitory circuit during postural adjustments elicited by labyrinthine input.
在八名人类受试者中，研究了矢状面内静态头身倾斜对与比目鱼肌伸肌α运动神经元耦合的闰绍细胞活动的影响。使用倾斜座椅进行头身旋转，并在80度（正常坐姿）和40度向后倾斜（鼻尖向上）时评估其效果。闰绍细胞活动通过Bussel和Pierrot - Deseilligny首次描述的一种专门设计的配对H反射方法进行评估。α运动神经元兴奋性也通过绘制参考H反射幅度作为静态头身位移的函数进行独立研究。在几乎所有受试者中，相对于80度时的对照值，在40度向后倾斜时闰绍细胞活动增加。这些变化归因于当身体从直立位置向后倾斜时能够使闰绍细胞活动与其运动神经元解耦的紧张性迷路反射。我们讨论了由迷路输入引起的姿势调整过程中回返抑制回路的假设功能模式。
