Lesion in the lateral cerebellum specifically produces overshooting of the toe trajectory in leading forelimb during obstacle avoidance in the rat
Lesion in the lateral cerebellum specifically produces overshooting of the toe trajectory in leading forelimb during obstacle avoidance in the rat
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DOI：
10.1152/jn.01048.2012
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发表时间：
2013-10-01
影响因子：
2.5
通讯作者：
Yanagihara, Dai
中科院分区：
文献类型：
--
作者：
Aoki, Sho;Sato, Yamato;Yanagihara, Dai
在运动过程中，在视觉引导下跨越障碍物对持续安全行走至关重要。关于中枢神经系统在踏步运动中的作用的研究主要集中在大脑皮层区域，如初级运动皮层和后顶叶皮层。有推测认为，侧小脑与大脑皮层有很强的解剖学联系，在跨越障碍物的行走运动中也起着关键作用，尽管侧小脑的这一功能尚未被阐明。在此，我们研究了外侧小脑损伤大鼠在避障运动中的作用。侧小脑单侧病变不影响地上运动时的肢体运动。然而，重要的是，当跨越障碍物时，受损动物表现出与病变同侧的前肢特有的脚趾轨迹过冲，并且脚趾的峰值位置（在踩踏过程中脚趾最大程度上升）偏离了障碍物的上边缘。肘关节屈肌和伸肌的肌电活动记录表明，同侧前肢脚趾过伸轨迹可能是由于肱二头肌长时间活动后肘关节持续屈曲和肘关节延迟伸展所致。这些结果表明，外侧小脑特别有助于在同侧前肢产生适当的脚趾轨迹，并在跨越障碍物时控制相关肌肉活动，特别是在视觉指导下实现对远端肢体的精确控制时。
During locomotion, stepping over an obstacle under visual guidance is crucial to continuous safe walking. Studies of the role of the central nervous system in stepping movements have focused on cerebral cortical areas such as the primary motor cortex and posterior parietal cortex. There is speculation that the lateral cerebellum, which has strong anatomical connections with the cerebral cortex, also plays a key role in stepping movements over an obstacle, although this function of the lateral cerebellum has not yet been elucidated. Here we investigated the role of the lateral cerebellum during obstacle avoidance locomotion in rats with a lateral cerebellar lesion. A unilateral lesion in the lateral cerebellum did not affect limb movements during overground locomotion. Importantly, however, the lesioned animals showed overshooting of the toe trajectory specific to the leading forelimb ipsilateral to the lesion when stepping over an obstacle, and the peak toe position, in which the toe is maximally raised during stepping, shifted away from the upper edge of the obstacle. Recordings of EMG activity from elbow flexor and extensor muscles suggested that the overshooting toe trajectory in the ipsilateral leading forelimb possibly resulted from sustained elbow flexion and delayed elbow extension following prolonged activity of the biceps brachii. These results suggest that the lateral cerebellum specifically contributes to generating appropriate toe trajectories in the ipsilateral leading forelimb and to controlling related muscle activities in stepping over an obstacle, especially when accurate control of the distal extremity is achieved under visual guidance.