Department of Physiology, School of Medicine, Hokkaido University, Sapporo, Japan.
Invest Ophthalmol Vis Sci. 2011 Jun 1;52(6):3458-67. doi: 10.1167/iovs.10-5903.
Juvenile monkeys being trained on smooth-pursuit tasks exhibit ocular oscillations resembling pendular nystagmus. The purpose of this study was to analyze these oscillations, the effects of gabapentin on them, and responses of cerebellar floccular neurons to understand possible neuronal mechanisms.
Four monkeys were trained for horizontal and vertical smooth pursuit; in two, saccades were also tested. Frequency, peak-to-peak eye velocity, and amplitude of the ocular oscillations were measured. In one monkey, the effect of gabapentin on the oscillations was measured, and oscillation-related neuronal discharge was recorded in the cerebellar floccular region.
Ocular oscillations, with features of pendular nystagmus, appeared early during training of both horizontal and vertical pursuit in all four monkeys. Although these oscillations were observed both in the direction of pursuit and orthogonally, the velocity and amplitude of oscillation were larger in the direction of pursuit, implicating pursuit mechanisms in their generation. Corrective saccades were often superimposed on the oscillations during pursuit and fixation. Gabapentin suppressed oscillations in the monkey tested. Recordings in the floccular region revealed a subset of neurons discharged during both the oscillations and corrective saccades. Many of them exhibited burst-tonic discharge during visually guided saccades, similar to discharge of brain stem burst-tonic neurons, suggesting contributions of the neural integrator to the oscillations.
The developmentally transient ocular oscillations occurring in monkeys during pursuit training has properties resembling pendular nystagmus. Both smooth pursuit and a neural integrator may contribute to these ocular oscillations. Analysis using an efference-copy pursuit model supports the interpretation herein.
在进行平滑追踪任务训练的幼年猴子会表现出类似于钟摆性眼球震颤的眼动震颤。本研究旨在分析这些震颤、加巴喷丁对其的影响以及小脑绒球神经元的反应，以了解可能的神经元机制。
4 只猴子接受了水平和垂直平滑追踪训练；其中 2 只猴子还接受了扫视测试。测量了眼动震颤的频率、峰峰值眼速和振幅。在一只猴子中，测量了加巴喷丁对震颤的影响，并记录了小脑绒球区与震颤相关的神经元放电。
在所有 4 只猴子的水平和垂直追踪训练早期，都出现了具有钟摆性眼球震颤特征的眼动震颤。尽管这些震颤在追踪和正交方向上都有观察到，但在追踪方向上的震颤速度和振幅更大，提示追踪机制参与了其产生。在追踪和注视期间，常叠加有校正性扫视。在接受测试的猴子中，加巴喷丁抑制了震颤。绒球区的记录显示，有一小部分神经元在震颤和校正性扫视期间放电。其中许多在视觉引导的扫视期间表现出爆发-紧张放电，类似于脑干爆发-紧张神经元的放电，表明神经整合器对震颤的贡献。
在猴子进行追踪训练期间出现的发育性短暂性眼动震颤具有类似于钟摆性眼球震颤的特征。平滑追踪和神经整合器都可能对这些眼动震颤有贡献。使用传出复制追踪模型的分析支持了本文的解释。
