The variable gain element of the vestibulo-ocular reflex is common to the optokinetic system of the cat.
The variable gain element of the vestibulo-ocular reflex is common to the optokinetic system of the cat.
复制标题
前庭眼反射的可变增益元件是猫的视动系统所共有的。
DOI：
10.1016/0006-8993(81)90740-x
复制
发表时间：
1981
期刊：
影响因子：
2.9
通讯作者：
Demer,JL
中科院分区：
文献类型：
--
作者：
Demer,JL
通过长期佩戴视觉反转或2倍放大眼镜，结合在光线下强制旋转，将6只警觉猫的前庭眼反射（VOR）增益（慢相眼速度/头速度）依次调整至0.2至1.66之间的值。在黑暗中以0.05 Hz的峰值速度约30°/s的正弦振荡期间测量增益。在VOR增益适应的每个状态下，在全视野视动鼓中以20-80°/s的速度测量视动性眼震（OKN）和视动性后眼震（OKAN）。稳态，慢相，视动眼速度几乎等于低鼓速度，但在较高的速度饱和，并下降时鼓速度进一步增加。饱和速度随VOR增益而变化，范围从VOR增益为0.2-0.4时的20-20°/s到VOR增益为1.66时的65°/s。这意味着VOR的可变增益元件由视动系统（OKS）共享。在黑暗中测量的OKAN大致呈指数衰减。OKAN（Tokan）的时间常数也随VOR增益而变化，范围从VOR增益为0.2时的约2 s到VOR增益为1.66时的10 s。这是一个新的发现，表明速度存储机制也受到增益变化的影响。提出了一种模型，其中一个神经，可变增益元件位于一个正反馈，速度存储回路共同的VOR和OKS。计算机模拟结果表明，这一假设可以解释OKN饱和度和TOKAN随VOR增益变化的大部分现象。该模型还预测，在黑暗中的低频VOR的相位领先应增加降低VOR增益。0.05 Hz时的实验VOR相位超前从VOR增益高于1.1时的约10°变化到VOR增益低于0.3时的约50°。这种相位超前数据与模型预测的趋势一致。
The gain (slow-phase eye velocity/head velocity) of the vestibulo-ocular reflex (VOR) of 6 alert cats was sequentially adapted to values between 0.2 and 1.66 by the chronic wearing of visual reversing or 2 X magnifying spectacles, combined with forced rotation in the light. Gain was measured during sinusoidal oscillation in darkness at 0.05 Hz at a peak velocity of about 30°/s. In each state of VOR gain adaptation, optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN) were measured in a full-field optokinetic drum at velocities of 20-80°/s. Steady-state, slow-phase, optokinetic eye velocity nearly equaled low drum velocities, but saturated at higher velocities and declined when drum velocity further increased. The saturation velocity varied in relation to VOR gain, ranging from 20-20°/s at a VOR gain of 0.2–0.4, to 65°/s at a VOR gain of 1.66. This means that the variable gain element of the VOR is shared by the optokinetic system (OKS).OKAN, measured in darkness, had a roughly exponential decay. The time constant of OKAN (Tokan) also varied with VOR gain, ranging from about 2 s at a VOR gain of 0.2, to 10 s at a VOR gain of 1.66. This is a novel finding which suggests that the velocity-storage mechanism was also affected by gain changes. A model is proposed in which a neural, variable-gain element is located in a positive-feedback, velocity-storage loop common to both the VOR and the OKS. Computer simulation showed that this hypothesis could account for most of the observed changes in OKN saturation and TOKANwith changes in VOR gain. The model also predicts that low frequency VOR phase lead in darkness should increase with decreasing VOR gain. Experimental VOR phase lead at 0.05 Hz varied from about 10° for VOR gains above 1.1, to about 50° for VOR gains below 0.3. Such phase-lead data agree with the trend predicted by the model.