Department of Neurology, University of Zurich, Zurich, Switzerland.
J Vestib Res. 2011;21(5):251-66. doi: 10.3233/VES-2011-0425.
Visuo-vestibular interactions in monkeys can be accurately modelled using the classical Raphan and Cohen's model. This model is composed of direct vestibular and visual contributions to the vestibulo-ocular reflex (VOR) and of a velocity storage. We applied this model to humans and estimated its parameters in a series of experiments: yaw rotations at moderate (60°/s) and high velocities (240°/s), suppression of the VOR by a head-fixed wide-field visual stimulus, and optokinetic stimulation with measurements of optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN). We found the velocity storage time constant to be 13 s, which decreased to 8 s during visual suppression. OKAN initial velocity was 12% of the OKN stimulus velocity. The gain of the direct visual pathway was 0.75 during both visual suppression and OKN; however, the visual input to the velocity storage was higher during visual suppression than during OKN. We could not estimate the time constant of the semicircular canals accurately. Finally, we inferred from high-velocity rotations that the velocity storage saturates around 20-30°/s. Our results indicate that the dynamics of visuo-vestibular interactions in humans is similar as in monkeys. The central integration of visual cues, however, is weaker in humans.
猴子的视-前庭相互作用可以用经典的 Raphan 和 Cohen 模型准确模拟。该模型由前庭眼反射 (VOR) 的直接前庭和视觉贡献以及速度存储组成。我们将该模型应用于人类，并在一系列实验中估计了其参数：中速（60°/s）和高速（240°/s）的偏航旋转、头部固定的宽视场视觉刺激对 VOR 的抑制，以及使用视动性眼球震颤（OKN）和视动后眼球震颤（OKAN）测量的视动刺激。我们发现速度存储时间常数为 13 秒，在视觉抑制期间降至 8 秒。OKAN 初始速度为 OKN 刺激速度的 12%。在视觉抑制和 OKN 期间，直接视觉通路的增益均为 0.75；然而，在视觉抑制期间，视觉输入到速度存储的速度高于在 OKN 期间。我们无法准确估计半规管的时间常数。最后，我们从高速旋转推断出速度存储在 20-30°/s 左右饱和。我们的结果表明，人类的视-前庭相互作用动力学与猴子相似。然而，人类的视觉线索的中枢整合较弱。
