Lacour M, Xerri C, Hugon M
Exp Brain Res. 1979;37(3):563-80. doi: 10.1007/BF00236824.
The electromyographic (EMG) responses from soleus and tibialis anterior muscles and the monosynaptic H- and T-reflex responses from soleus muscles were recorded bilaterally from conscious baboon while unexpectedly dropping it with unrestricted vision. These responses were recorded either after unilateral vestibular neurectomy (U.N. Baboons) or after bilateral neurectomy performed in one stage (B.N. 1 baboons) and in two stages (B.N. 2 baboons). A positive correlation was found between modifications and development of EMG responses and reflex data. In the U.N. baboons, some differences were observed when comparing data from the H- and T-reflex methods, suggesting that recovery of normal responses to fall is achieved both by means of direct influences on alpha-motoneurons and via the gamma-loop. In the U.N. baboons postural reactions to fall developed in three distinct periods. The first or critical stage showed asymmetrical EMG and reflex responses with increased responses from contralateral soleus muscle and decreased responses from ipsilateral soleus. Opposite effects were recorded from tibialis anterior flexor muscles. The second or acute stage which began around 4 to 7 days after surgery exhibited symmetrical, but very reduced, responses when compared to the control in soleus muscles, and symmetrical, but increased, responses from tibialis anterior muscles. This stage lasted until about the end of the second postoperative week and was followed by the third or compensatory stage during which EMG as well as reflex responses developed towards the control pattern in all tested muscles. Almost normal responses were recorded on both sides 3 weeks after surgery. Only a partial recovery was found in the B.N. 1 baboons, indicating that the contralateral remaining labyrinthine afferences constitute a necessary condition for the full compensation of postural reactions to fall in the case of unilateral vestibular neurectomy. The Bechterew's compensation was obtained in the B.N. 2 baboons. These results are discussed in relation with the general organization of the vestibulospinal pathways and with those concerning development of the postoperative activity at the vestibular nuclei level. A model of vestibular compensation achieved by means of a multisensory substitution process is suggested.
在有意识的狒狒身上，当意外让其自由落体（视野不受限）时，双侧记录比目鱼肌和胫骨前肌的肌电图（EMG）反应以及比目鱼肌的单突触H反射和T反射反应。这些反应在单侧前庭神经切除术（U.N.狒狒）后，或在一期进行双侧神经切除术（B.N. 1狒狒）以及分两期进行双侧神经切除术（B.N. 2狒狒）后进行记录。发现EMG反应和反射数据的改变与发展之间存在正相关。在U.N.狒狒中，比较H反射和T反射方法的数据时观察到一些差异，这表明对跌倒的正常反应恢复是通过对α运动神经元的直接影响以及通过γ环路实现的。在U.N.狒狒中，对跌倒的姿势反应在三个不同时期发展。第一个或关键阶段表现为不对称的EMG和反射反应，对侧比目鱼肌反应增强，同侧比目鱼肌反应减弱。胫骨前屈肌记录到相反的效应。第二个或急性期在手术后约4至7天开始，与对照组相比，比目鱼肌的反应对称但非常减弱，而胫骨前肌的反应对称但增强。这个阶段一直持续到术后第二周结束，随后是第三个或代偿期，在此期间所有测试肌肉的EMG以及反射反应都朝着对照模式发展。术后3周两侧记录到几乎正常的反应。在B.N. 1狒狒中仅发现部分恢复，这表明在单侧前庭神经切除的情况下，对侧剩余的迷路传入是姿势反应对跌倒进行完全代偿的必要条件。在B.N. 2狒狒中获得了别赫捷列夫补偿。结合前庭脊髓通路的总体组织以及关于前庭核水平术后活动发展的那些情况对这些结果进行了讨论。提出了一种通过多感觉替代过程实现前庭补偿的模型。
