Partial ablations of the flocculus and ventral paraflocculus in monkeys cause linked deficits in smooth pursuit eye movements and adaptive modification of the VOR
Partial ablations of the flocculus and ventral paraflocculus in monkeys cause linked deficits in smooth pursuit eye movements and adaptive modification of the VOR
复制标题
DOI：
10.1152/jn.00768.2000
复制
发表时间：
2002-02-01
影响因子：
2.5
通讯作者：
Lisberger, SG
中科院分区：
文献类型：
--
作者：
Rambold, H;Churchland, A;Lisberger, SG
在头部运动时，前庭反射（VOR）产生代偿性眼球运动以稳定视网膜上的视觉图像。当头部运动持续地与图像运动联系在一起时，反射的振幅在一生中不断地被校准，并经历适应，也称为运动学习。虽然小脑的小叶复合体对于VOR适应是必要的，但尚不清楚这种功能是位于其前部还是后部，分别由腹侧小叶和小叶组成。本文报道了5只猕猴的絮凝复合物部分病变的影响，这些病变是通过手术或立体定向注射3-硝基丙酸（3-NP）造成的。在病变前后，在正弦和阶梯斜面目标运动中测试眼球的平滑追踪运动。通过与猴子在正弦头部旋转过程中精确移动目标来测试VOR的取消。对照VOR在黑暗中头部正弦旋转和头部速度30度/秒脉冲时进行测试。通过让猕猴佩戴x2或x0.25光学镜片4-7天来研究VOR适应性。在两只猴子中，双侧病变切除了除1叶和2叶部分外的所有小叶，但在平滑追求、VOR适应或VOR取消方面没有产生任何缺陷。我们的结论是，小叶本身可能不是追求或VOR学习所必需的。在两只猴子中，包括大部分腹侧小梁旁的单侧病变产生了水平和垂直平滑追求的小缺陷，以及VOR适应和VOR取消的轻度损伤。我们得出结论，腹侧小梁旁对这两种行为都有贡献。在一只猴子中，小叶和腹侧小叶旁的双侧病变导致了严重的平滑追求缺陷和VOR取消，以及VOR适应能力的完全丧失。综合考虑这五种情况，在VOR学习和追求方面的缺陷大小之间存在很强的相关性。我们发现行为缺陷与腹侧小叶旁病变大小的相关性最强，与全小叶复合体的相关性较弱但显著，与小叶病变大小无相关性。我们得出结论：1)絮体复合体的病变导致了平滑追求和VOR适应的相关缺陷；2)该结构的相关部分主要位于腹侧小叶旁，尽管小叶可能参与其中。
The vestibuloocular reflex (VOR) generates compensatory eye movements to stabilize visual images on the retina during head movements. The amplitude of the reflex is calibrated continuously throughout life and undergoes adaptation, also called motor learning, when head movements are persistently associated with image motion. Although the floccular-complex of the cerebellum is necessary for VOR adaptation, it is not known whether this function is localized in its anterior or posterior portions, which comprise the ventral paraflocculus and flocculus, respectively. The present paper reports the effects of partial lesions of the floccular-complex in five macaque monkeys, made either surgically or with stereotaxic injection of 3-nitropropionic acid (3-NP). Before and after the lesions, smooth pursuit eye movements were tested during sinusoidal and step-ramp target motion. Cancellation of the VOR was tested by moving a target exactly with the monkey during sinusoidal head rotation. The control VOR was tested during sinusoidal head rotation in the dark and during 30degrees/s pulses of head velocity. VOR adaptation was studied by having the monkeys wear x2 or x0.25 optics for 4-7 days. In two monkeys, bilateral lesions removed all of the flocculus except for parts of folia 1 and 2 but did not produce any deficits in smooth pursuit, VOR adaptation, or VOR cancellation. We conclude that the flocculus alone probably is not necessary for either pursuit or VOR learning. In two monkeys, unilateral lesions including a large fraction of the ventral paraflocculus produced small deficits in horizontal and vertical smooth pursuit, and mild impairments of VOR adaptation and VOR cancellation. We conclude that the ventral paraflocculus contributes to both behaviors. In one monkey, a bilateral lesion of the flocculus and ventral paraflocculus produced severe deficits smooth pursuit and VOR cancellation, and a complete loss of VOR adaptation. Considering all five cases together, there was a strong correlation between the size of the deficits in VOR learning and pursuit. We found the strongest correlation between the behavior deficits and the size of the lesion of the ventral paraflocculus, a weaker but significant correlation for the full floccular complex, and no correlation with the size of the lesion of the flocculus. We conclude that 1) lesions of the floccular complex cause linked deficits in smooth pursuit and VOR adaptation, and 2) the relevant portions of the structure are primarily in the ventral paraflocculus, although the flocculus may participate.