Adaptive modification of the cat's vestibulospinal reflex during sustained and combined roll tilt of the whole animal and forepaw rotation: Cerebellar mechanisms
Adaptive modification of the cat's vestibulospinal reflex during sustained and combined roll tilt of the whole animal and forepaw rotation: Cerebellar mechanisms
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DOI：
10.1016/j.neuroscience.2004.11.060
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发表时间：
2005-01-01
期刊：
影响因子：
3.3
通讯作者：
Manzoni, D
中科院分区：
文献类型：
--
作者：
Andre, P;Pompeiano, O;Manzoni, D
在去大脑猫中，前肢肱三头肌伸肌（TB）的肌电图（EMG）活动在约0.15 Hz的整个动物的侧下滚动倾斜（前庭脊髓反射，VSR）期间增加。（+/- 10度），而在侧向上倾斜期间降低。另一方面，TB活动在同侧前爪的背侧屈曲（0.15Hz，+/-5度-10度）期间增加，但在腹侧屈曲期间减少。在六个实验中，这些刺激是协同相关的（侧下倾斜正好与前爪的背屈），因此，TB活动的EMG调制大于由单个刺激引起的。在3小时的持续刺激期间，纯VSR的振幅逐渐增加，在第三小时结束时达到最大值，并在适应后（1小时）保持不变。在三个实验中，动物倾斜和前爪旋转是拮抗相关的（侧下倾斜与前爪的腹侧屈曲一致）。在这些情况下，VSR增益平均保持稳定，但是，在3小时的联合刺激期结束时，TB对动物倾斜的反应比例显示出相位反转。在一个digitigrade的动物，如猫，腕关节的背侧屈曲与肢体长度的减少，并会发生时，伸肌张力是不适当的，以支持体重，因此，我们建议，体感截击引起的手腕旋转修改增益的VSR，以保持姿势稳定。失活，在一侧的肌肉记录，皮质小脑区域的项目到侧前庭核的Deiters，通过局部显微注射的GABA-A激动剂蝇蕈醇（0.5 μ l，16 μ g/gl），降低了已经适应的增益VSR。总之，本研究的结果表明，当动物倾斜期间外力导致脚的最终姿势发生变化时，对小脑蚓部的体感传入输入用于可塑性修改VSR的增益。(c)2005由Elsevier Ltd代表IBRO出版。
In decerebrate cats, the electromyogram (EMG) activity of the forelimb extensor triceps brachii (TB) increases during side-down roll tilt of the whole animal (vestibulospinal reflex, VSR) at about 0.15 Hz. (+/- 10 degrees), while decreases during side up tilt. On the other hand, the TB activity increases during dorsal flexion of the ipsilateral forepaw (0.15 Hz, +/- 5 degrees-10 degrees), but decreases during ventral flexion. In six experiments, these stimuli were synergistically associated (side-down tilt coincided with dorsal flexion of the forepaw), so that the EMG modulation of the TB activity was greater than that induced by the individual stimuli. During a 3-h period of this sustained stimulation, the amplitude of the pure VSR progressively increased to reach the maximum value at the end of the third hour and persisted unmodified during the post-adaptation period (1 h). In three experiments, animal tilt and forepaw rotation were antagonistically associated (side-down tilt coincided with ventral flexion of the forepaw). In these instances the VSR gain remained on the average stable, but, at the end of the 3-h period of combined stimulation, a proportion of TB responses to animal tilt showed a phase reversal. In a digitigrade animal like the cat, a dorsal flexion of the wrist is associated with a decrease in limb length and would occur when the extensor tone is not appropriate to support body weight; we propose, therefore, that somatosensory volleys elicited by wrist rotation modify the gain of VSR so as to maintain postural stability. Inactivation, on the side of muscle recording, of the corticocerebellar region which projects to the lateral vestibular nucleus of Deiters, by local microinjection of the GABA-A agonist muscimol (0.5 mu l at 16 mu g/gl), decreased the already adapted gain of VSR. In conclusion, the results of this study suggest that somatosensory reafferent inputs to the cerebellar vermis are used to plastically modify the gain of VSR, when external forces produce changes in the final posture of the foot during animal tilt. (c) 2005 Published by Elsevier Ltd on behalf of IBRO.