Fukushima K, Sato T, Fukushima J, Kurkin S
Department of Physiology, Hokkaido University School of Medicine, Sapporo, Japan.
Arch Ital Biol. 2000 Jan;138(1):49-62.
We have shown recently in alert monkeys that repeated interaction between the pursuit and vestibular systems in the orthogonal plane induces adaptive changes in the VOR. To examine further properties of adaptive cross axis VOR induced by pursuit training, sinusoidal whole body rotation was applied either in the pitch or yaw plane while presenting a target spot that moved orthogonally to the rotation plane with either 90 degrees phase-lead or 90 degrees phase-lag to the chair signal. After one hour of training at 0.5 Hz (+/- 10 degrees), considerable phase-shift was observed in orthogonal eye movement responses consistent with the training paradigms by identical chair rotation in complete darkness, with further lead at lower frequencies and lag at higher frequencies. However, gains (eye/chair) induced by phase- shift pursuit training was different during pitch and yaw rotation. Although frequency tuning was maintained during pitch in the phase-shift paradigms, it was not maintained during yaw, resulting in higher gains at lower stimulus frequencies compared to the gains during yaw. This difference may reflect otolith contribution during pitch rotation. To understand further the nature of signals that induce adaptive cross axis VOR, we examined interaction of pursuit, whole field-visual pattern and vestibular stimuli. Magnitudes of the cross axis VOR with a spot alone on one hand and with a spot and pattern moving together in the same plane on the other during chair rotation were similar, and when one of the two visual stimuli was stationary during chair rotation, our well trained monkeys did not induce the cross axis VOR. These results suggest that the cross axis VOR induced by pursuit training shares common mechanisms with the cross axis VOR induced by whole field-slip stimuli and that if conflicting information is given between the two visual stimuli, adaptive changes are inhibited. Horizontal GVPs were recorded in the cerebellar floccular lobe during pitch rotation coupled with horizontal pursuit stimuli. These GVPs did not respond to pitch in the dark before training, but responded after 60 min of pursuit training with eye velocity sensitivities similar to those before training. Adaptive change in the VOR was specific to smooth eye movements but not to saccades in our paradigms.
我们最近在警觉的猴子身上发现，在正交平面上，追踪系统和前庭系统之间的反复相互作用会引起前庭眼反射（VOR）的适应性变化。为了进一步研究追踪训练诱导的适应性交叉轴VOR的特性，在俯仰或偏航平面施加正弦全身旋转，同时呈现一个目标点，该目标点相对于旋转平面正交移动，相对于座椅信号有90度的相位超前或90度的相位滞后。在0.5Hz（±10度）下训练一小时后，在完全黑暗中通过相同的座椅旋转，在正交眼动反应中观察到与训练范式一致的显著相位偏移，在较低频率下有进一步的超前，在较高频率下有滞后。然而，在俯仰和偏航旋转期间，相位偏移追踪训练诱导的增益（眼/椅）有所不同。尽管在相位偏移范式中俯仰期间频率调谐得以维持，但在偏航期间却没有维持，导致与偏航期间的增益相比，在较低刺激频率下有更高的增益。这种差异可能反映了俯仰旋转期间耳石的作用。为了进一步了解诱导适应性交叉轴VOR的信号的性质，我们研究了追踪、全场视觉模式和前庭刺激之间的相互作用。在座椅旋转期间，单独一个点时的交叉轴VOR幅度与一个点和模式在同一平面一起移动时的交叉轴VOR幅度相似，并且当在座椅旋转期间两个视觉刺激之一静止时，我们训练有素的猴子不会诱导出交叉轴VOR。这些结果表明，追踪训练诱导的交叉轴VOR与全场滑动刺激诱导的交叉轴VOR具有共同机制，并且如果在两个视觉刺激之间给出相互冲突的信息，适应性变化就会受到抑制。在俯仰旋转与水平追踪刺激相结合的过程中，在小脑绒球叶记录水平凝视前庭诱发电位（GVPs）。这些GVPs在训练前的黑暗中对俯仰没有反应，但在追踪训练60分钟后有反应，其眼速度敏感性与训练前相似。在我们的范式中，VOR的适应性变化特定于平滑眼动而非扫视。
