Effects of lesions of the oculomotor cerebellar vermis on eye movements in primate: smooth pursuit.
Effects of lesions of the oculomotor cerebellar vermis on eye movements in primate: smooth pursuit.
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DOI：
10.1152/jn.2000.83.4.2047
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发表时间：
2000-04
影响因子：
2.5
通讯作者：
M. Takagi;D. Zee;R. Tamargo
中科院分区：
文献类型：
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作者：
M. Takagi;D. Zee;R. Tamargo
我们研究了在三只猴子中，小脑核被保留的背侧小脑蚓部（病变集中在小叶VI和VII）消融对平滑追踪眼球运动的影响。病变后，追踪启动的延迟时间未发生变化。猴子在三角波跟踪过程中的增益略有下降（高达15%）。更引人注目的是变化的动态特性的追求确定在开环期间（第一个100毫秒）的平滑跟踪。变化包括峰值眼加速度的降低（例如，在一只猴子中从大约650度/秒（2），损伤前到大约220-380度/秒（2），损伤后），并且在开环期结束时速度降低[例如，在另一只猴子中，从损伤前的0.93的增益（眼速度/100 ms跟踪时的目标速度）到损伤后的0.53]。在猴子个体中，开环追踪期的缺陷模式通常与眼跳的缺陷模式相当，特别是当比较追踪加速度的变化与眼跳速度的变化时。这些发现支持了这样的假设，即扫视和开环期间的追求是由小脑蚓部以类似的方式控制。扫视可以通过眼睛速度命令来生成以将眼睛带到特定位置，并且通过眼睛加速度命令来追踪以将眼睛带到特定速度。另一方面，在三角波跟踪过程中的增益变化并不相关的眼跳或开环追求赤字，这意味着不同的贡献的眼蚓部的开环和持续部分的追求跟踪。最后，在一个追求适应范例（x0.5或x2，分别要求眼睛速度减半或加倍）完整的动物可以自适应地调整眼加速度在开环期间。变化的主要模式是x0.5训练的峰值加速度下降，x2训练的峰值加速度持续时间增加。眼蚓部病变后，这种适应能力受损。总之，对于眼跳，眼蚓部在即时在线和短期自适应控制中起着关键作用。
We studied the effects on smooth pursuit eye movements of ablation of the dorsal cerebellar vermis (lesions centered on lobules VI and VII) in three monkeys in which the cerebellar nuclei were spared. Following the lesion the latencies to pursuit initiation were unchanged. Monkeys showed a small decrease (up to 15%) in gain during triangular-wave tracking. More striking were changes in the dynamic properties of pursuit as determined in the open-loop period (the 1st 100 ms) of smooth tracking. Changes included a decrease in peak eye acceleration (e.g., in one monkey from approximately 650 degrees /s(2), prelesion to approximately 220-380 degrees /s(2), postlesion) and a decrease in the velocity at the end of the open-loop period [e.g., in another monkey from a gain (eye velocity/target velocity at 100 ms of tracking) of 0.93, prelesion to 0.53, postlesion]. In individual monkeys, the pattern of deficits in the open-loop period of pursuit was usually comparable to that of saccades, especially when comparing the changes in the acceleration of pursuit to the changes in the velocity of saccades. These findings support the hypothesis that saccades and the open-loop period of pursuit are controlled by the cerebellar vermis in an analogous way. Saccades could be generated by eye velocity commands to bring the eyes to a certain position and pursuit by eye acceleration commands to bring the eyes toward a certain velocity. On the other hand, changes in gain during triangular-wave tracking did not correlate with either the saccade or the open-loop pursuit deficits, implying different contributions of the oculomotor vermis to the open loop and to the sustained portions of pursuit tracking. Finally, in a pursuit adaptation paradigm (x0.5 or x2, calling for a halving or doubling of eye velocity, respectively) intact animals could adaptively adjust eye acceleration in the open-loop period. The main pattern of change was a decrease in peak acceleration for x0.5 training and an increase in the duration of peak acceleration for x2 training. Following the lesion in the oculomotor vermis, this adaptive capability was impaired. In conclusion, as for saccades, the oculomotor vermis plays a critical role both in the immediate on-line and in the short-term adaptive control of pursuit.