Gahéry Y, Pompeiano O, Coulmance M
Arch Ital Biol. 1984 Jun;122(2):129-54.
Unilateral neck deafferentation produces in cats a postural asymmetry, characterized by an increase in the extensor activity of the ipsilateral limbs and a decreased activity in the contralateral limbs; moreover, the placing reactions are severely depressed in the ipsilateral limbs. The present experiments were performed to investigate the influence of unilateral section of the cervical dorsal roots C1-C2 or C1-C3 on the postural adjustments occurring during flexion limb movements induced by cortical stimulation in chronically implanted cats. Only weak stimulations were used and motor activity was mainly isometric, to facilitate quantification of responses analyzed by measuring changes in vertical force exerted at the level of each limb in the up-right position of the animal. The results obtained were the following. The general motor behaviour of the animal was not affected by the lesion. In particular, stimulation of the motor cortex evoked not only flexion movement of a contralateral limb but also an initial postural adjustment consisting of a diagonal force pattern. The response threshold of the moving limb increased on the hypertonic side and decreased on the hypotonic side. Moreover, the changes in threshold of the performing limb following unilateral neck deafferentation were coupled with parallel changes in threshold of the limbs involved in the postural adjustment. There were great quantitative modifications both of the movement and the postural adjustment after the neck deafferentation. In fact weight shift latencies increased when the performing limb was ipsilateral to the hypertonic side, while the weight shifts themselves decreased in amplitude and speed. The opposite occurred when the performing limb was ipsilateral to the hypotonic side. Parallel with these changes, the slope of the response curve of the moving limb as well as of the limbs involved in the postural adjustment decreased following stimulation of the motor cortex at different stimulus intensities if the performing limb was ipsilateral to the hypertonic side, but increased if the performing limb was ipsilateral to the hypotonic side. These changes compensated after chronic neck deafferentation. In summary, the results indicate that well coordinated posturo-kinetic responses were still elicited by cortical stimulation in spite of the prominent changes in posture and reflex movements induced by unilateral neck deafferentation. In particular, changes in threshold, latency, amplitude and speed of the force changes under the limb making a movement were coupled with parallel alterations of the force changes under the limbs undergoing postural adjustment.(ABSTRACT TRUNCATED AT 400 WORDS)
单侧颈部去传入神经支配会使猫产生姿势不对称，其特征为同侧肢体伸肌活动增加，对侧肢体活动减少；此外，同侧肢体的放置反应严重受抑制。进行本实验是为了研究在长期植入电极的猫中，单侧切断颈背根C1 - C2或C1 - C3对皮层刺激诱发的屈肢运动过程中发生的姿势调整的影响。仅使用微弱刺激，且运动活动主要为等长收缩，以便通过测量动物直立位时各肢体水平施加的垂直力的变化来促进对反应的量化分析。得到的结果如下。动物的一般运动行为不受损伤影响。具体而言，刺激运动皮层不仅会诱发对侧肢体的屈肌运动，还会引发由对角力模式组成的初始姿势调整。运动肢体的反应阈值在高张力侧升高，在低张力侧降低。此外，单侧颈部去传入神经支配后，执行运动肢体的阈值变化与姿势调整中涉及的肢体阈值的平行变化相关联。颈部去传入神经支配后，运动和姿势调整都有很大的定量改变。实际上，当执行运动肢体与高张力侧同侧时，体重转移潜伏期延长，而体重转移本身的幅度和速度减小。当执行运动肢体与低张力侧同侧时，情况则相反。与这些变化同时发生的是，如果执行运动肢体与高张力侧同侧，在不同刺激强度下刺激运动皮层后，运动肢体以及参与姿势调整的肢体的反应曲线斜率会降低，但如果执行运动肢体与低张力侧同侧，则斜率会增加。这些变化在慢性颈部去传入神经支配后得到补偿。总之，结果表明，尽管单侧颈部去传入神经支配会引起姿势和反射运动的显著变化，但皮层刺激仍能引发协调良好的姿势 - 运动反应。特别是，进行运动的肢体下方力变化的阈值、潜伏期、幅度和速度的变化与进行姿势调整的肢体下方力变化的平行改变相关联。（摘要截断于400字）
