Rossi A, Mazzocchio R
Institute of Neurological Sciences, University of Siena, Italy.
ORL J Otorhinolaryngol Relat Spec. 1988;50(2):119-26. doi: 10.1159/000275979.
The present experiments were made in man with the aim of studying the possible influences of different head-body tilts on the activity of the interneurons Ia, Ib and the Renshaw cells functionally coupled to the soleus alpha-motoneurons. Subjects were seated on a chair, rotable with respect to the vertical axis, and were studied at 80 degrees and 40 degrees to the horizontal. The excitability of the soleus alpha-motoneurons slightly decreased when the body was placed at 40 degrees of backward inclination whereas the Renshaw cell activity showed a reinforcement of inhibition on the same motoneurons. The reciprocal inhibition from the anterior tibial to the soleus muscle increased at 40 degrees of backward inclination with respect to the control values at 80 degrees. Finally, short-latency homonymous facilitation and inhibition showed no significant change in relation to body position. The results indicate that different head-body positions are able to modify the bias of spinal interneurons in man. We discuss the hypothetical role of the vestibular system in producing the effects seen.
本实验以人体为对象，旨在研究不同头身倾斜度对与比目鱼肌α运动神经元功能耦合的Ia、Ib中间神经元以及闰绍细胞活性的可能影响。受试者坐在一把可绕垂直轴旋转的椅子上，在与水平呈80度和40度的角度下进行研究。当身体向后倾斜40度时，比目鱼肌α运动神经元的兴奋性略有下降，而闰绍细胞活性显示对相同运动神经元的抑制增强。相对于80度时的对照值，在向后倾斜40度时，从胫骨前肌到比目鱼肌的交互抑制增加。最后，短潜伏期的同侧易化和抑制与身体位置无关，无显著变化。结果表明，不同的头身位置能够改变人体脊髓中间神经元的偏向性。我们讨论了前庭系统在产生所见效应中的假设作用。
