DISSOCIATION OF THE LATERAL AND MEDIAL CEREBELLUM IN MOVEMENT TIMING AND MOVEMENT EXECUTION
DISSOCIATION OF THE LATERAL AND MEDIAL CEREBELLUM IN MOVEMENT TIMING AND MOVEMENT EXECUTION
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DOI：
10.1007/bf00279670
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发表时间：
1988-01-01
影响因子：
2
通讯作者：
DIENER, HC
中科院分区：
文献类型：
--
作者：
IVRY, RB;KEELE, SW;DIENER, HC
在之前的一项研究中(艾弗里和基尔，在出版中)，小脑患者被发现在需要准确计时的运动和知觉任务上都受到了损害。本文报告了7例小脑局灶性病变的病例研究分析。其中4例患者的病变主要位于外侧半球区域。其余3例，病变集中在小脑内侧带附近。患者的临床评价也与不同的病变部位一致：外侧病变主要损害精细运动协调，尤其是与远端肢体的运动，内侧病变主要扰乱平衡和步态。所有患者在用病变同侧的效应器(手指或脚)敲击时，与使用对侧效应器时相比，在进行有节奏的敲击时，变异性都增加了。根据Wing和Kristofferson(1973)开发的模型，从总变异性分数中得出中央计时器组件和执行组件的可分离估计。这一分析表明，侧支病变患者的表现不佳可归因于中央计时过程中的缺陷。相比之下，内侧病变的患者能够准确地确定何时做出反应，但无法在期望的时间实施反应。在小脑萎缩患者的时间知觉任务中，也观察到了外侧和内侧区域之间类似的分离。结论是，小脑的外侧区域对于内部计时系统的准确运作至关重要。
In a previous study (Ivry and Keele, in press), cerebellar patients were found to be impaired on both a motor and a perceptual task which required accurate timing. This report presents case study analyses of seven patients with focal lesions in the cerebellum. The lesions were predominantly in the lateral, hemispheric regions for four of the patients. For the remaining three patients, the lesions were centered near the medial zone of the cerebellum. The clinical evaluation of the patients also was in agreement with the different lesion foci: lateral lesions primarily impaired fine motor coordination, especially apparent in movements with the distal extremities and medial lesions primarily disturbed balance and gait. All of the patients were found to have increased variability in performing rhythmic tapping when tapping with an effector (finger or foot) ipsilateral to the lesion in comparison to their performance with a contralateral effector. Separable estimates of a central timekeeper component and an implementation component were derived from the total variability scores following a model developed by Wing and Kristofferson (1973). This analysis indicated that the poor performance of patients with lateral lesions can be attributed to a deficit in the central timing process. In contrast, patients with medial lesions are able to accurately determine when to make a response, but are unable to implement the response at the desired time. A similar dissociation between the lateral and medial regions has been observed on a time perception task in patients with cerebellar atrophy. It is concluded that the lateral regions of the cerebellum are critical for the accurate functioning of an internal timing system.