Effects of lesions of the oculomotor vermis on eye movements in primate: Saccades
Effects of lesions of the oculomotor vermis on eye movements in primate: Saccades
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DOI：
10.1152/jn.1998.80.4.1911
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发表时间：
1998-10-01
影响因子：
2.5
通讯作者：
Tamargo, RJ
中科院分区：
文献类型：
--
作者：
Takagi, M;Zee, DS;Tamargo, RJ
我们研究了三只猴子的小脑背侧蚓部（病变集中在小叶VI和Vn）消融对扫视的影响，其中小脑深核幸免。一只对称性病变的动物显示双侧高测量水平扫视。两个动物，不对称的病变，表现出hypometric同侧扫视，和扫视垂直定位的目标是错误的，通常偏离水平扫视是hypometric的一侧。损伤后，所有动物的扫视幅度的试验间变异性均增加（2- 5倍）。他们还显示了向心和离心扫视幅度之比的变化（轨道位置效应）;通常离心扫视变得更小。在两个不对称病变的动物，眼跳的高方向，lavelet显着增加（高达类似500毫秒）。也有一个表达和预期眼跳的高度方向的缺乏。当整体扫视潜伏期增加时，离心扫视变得比向心扫视相对更延迟。扫视的动力学特征在一定程度上受到影响，在所有猴子的峰值速度，眼睛加速度的变化，特别是眼睛减速。然而，除了一只动物显示出眼睛加速的轨道位置效应外，轨道位置对扫视动力学的影响相对较小。在一个双步骤的适应范例，动物表现出受损的能力，自适应调整眼跳幅度，虽然幅度变化postlesion可能发挥了作用，在这种赤字。然而，在一次训练中，矫正性眼扫视的潜伏期（损伤后增加）逐渐减少，从而使动物能够更快地到达目标的最终位置。总体而言，无论是在早期postlesion期间和恢复期间，眼跳幅度和潜伏期的变化往往变化在一起，但不与眼跳动力学或适应能力，这两个表现相对独立的变化。这些结果表明，小脑可以独立调节眼跳幅度和眼跳动力学。我们的研究结果牵连小脑蚓部直接在各个方面的在线控制扫视：启动（潜伏期），准确性（幅度和方向），和动态（速度和加速度），也在收购自适应眼运动行为。
We studied the effects on saccades of ablation of the dorsal cerebellar vermis (lesions centered on lobules VI and Vn) in three monkeys in which the deep cerebellar nuclei were spared. One animal, with a symmetrical lesion, showed bilateral hypometric horizontal saccades. Two animals, with asymmetrical lesions, showed hypometric ipsilateral saccades, and saccades to vertically positioned targets were misdirected, usually deviating away from the side to which horizontal saccades were hypometric. Postlesion, all animals showed an increase (2- to 5-fold) in trial-to-trial variability of saccade amplitude. They also showed a change in the ratio of the amplitudes of centripetal to centrifugal saccades (orbital-position effect); usually centrifugal saccades became smaller. In the two animals with asymmetrical lesions, for saccades in the hypometric direction, latencies were markedly increased (up to similar to 500 ms). There was also an absence of express and anticipatory saccades in the hypometric direction. When overall saccade latency was increased, centrifugal saccades became relatively more delayed than centripetal saccades. The dynamic characteristics of saccades were affected to some extent in all monkeys with changes in peak velocity, eye acceleration, and especially eye deceleration. There was relatively little effect of orbital position on saccade dynamics, however, with the exception of one animal that showed an orbital position effect for eye acceleration. In a double-step adaptation paradigm, animals showed an impaired ability to adaptively adjust saccade amplitude, though increased amplitude variability postlesion may have played a role in this deficit. During a single training session, however, the latency to corrective saccsdes-which had been increased postlesion-gradually decreased and so enabled the animal to reach the final position of the target more quickly. Overall, both in the early postlesion period and during recovery, changes in saccade amplitude and latency tended to vary together but not with changes in saccade dynamics or adaptive capability, both of which behaved relatively independently. These findings suggest that the cerebellum can adjust saccade amplitude and saccade dynamics independently. Our results implicate the cerebellar vermis directly in every aspect of the on-line control of saccades: initiation (latency), accuracy (amplitude and direction), and dynamics (velocity and acceleration) and also in the acquisition of adaptive ocular motor behavior.