Cerebellar activation during optokinetic stimulation and saccades
Cerebellar activation during optokinetic stimulation and saccades
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DOI：
10.1212/wnl.54.1.148
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发表时间：
2000-01-11
期刊：
影响因子：
9.9
通讯作者：
Brandt, T
中科院分区：
文献类型：
--
作者：
Dieterich, M;Bucher, SF;Brandt, T
目的：应用功能磁共振成像（fMRI）研究小视场光动力刺激（OKN）时小脑结构的激活模式，并与自发性扫视和OKN固定抑制时的结果进行比较。方法：对8名健康右撇子志愿者的斜横切面进行高空间分辨率、单片、快速低角度拍摄（FLASH）脉冲序列扫描。结果：水平OKN和扫视与双侧小脑半球（上半月小叶、单小叶、四边形小叶、下半月小叶）、小脑中脚、齿状核以及小脑核孔口和小舌内侧的活动有关。OKN和扫视的激活模式和程度与刺激方向无关。在固定抑制期间，激活程度明显减弱（半球）甚至缺失（小舌，culmen）。结论：注视抑制对这种复杂的小脑激活模式的不同影响在一定程度上使我们能够将视觉和注意从眼运动加工中分离出来。我们的数据与前庭脊髓和光动反射中眼运动过程和运动学习的行为和生理动物数据一致。这表明，小脑半球的活动可能主要与注意力的变化有关，而整体活动似乎与眼运动控制有关，而齿状核和小脑脚的活动似乎与两者都有关。
Objective: To investigate the activation pattern of cerebellar structures during small-field optokinetic stimulation (OKN) by functional MRI (fMRI) and compare it with that obtained during voluntary saccades and fixation suppression of OKN. Methods: Functional images were acquired from oblique transverse slices of eight healthy, right-handed volunteers using st radio frequency-spoiled, single-slice, fast low-angle shot (FLASH) pulse sequence with high-spatial resolution. Results: Horizontal OKN and saccades were associated with bilateral activity in the cerebellar hemispheres (superior semilunar lobule, simple lobule, quadrangular lobule, inferior semilunar lobule), the middle cerebellar peduncle, the dentate nucleus, and medially in the culmen and uvula of cerebellar nuclei. The pattern and extent of activation were independent of the stimulus direction for OKN and saccades. During fixation suppression, the extent of activation was significantly diminished (hemispheres) or even absent (uvula, culmen). Conclusion: The differential effects of fixation suppression on this complex pattern of cerebellar activation in part allow us to separate visual and attentional from ocular motor processing. Our data agree with behavioral and physiologic animal data about ocular motor processes and motor learning in the vestibulospinal and optokinetic reflex. This suggests that hemispheric cerebellar activity may be mainly associated with changes in attention, whereas vermal activity seems to be associated with ocular motor control, and activity of the dentate nuclei and the cerebellar peduncles seems to be associated with both.