Lisberger S G, Miles F A, Optican L M
J Neurosci. 1983 Jun;3(6):1234-44. doi: 10.1523/JNEUROSCI.03-06-01234.1983.
The vestibulo-ocular reflex (VOR) is under long-term adaptive regulation to minimize retinal image slip during head movement; normally this process keeps VOR gain (eye velocity divided by head velocity) near 1.0. It has been common to think of the adaptive mechanism as a single pure gain element, although some properties of the system (e.g., frequency-selective changes in the gain of the VOR) argue that it must be more complex. We now report new observations on the frequency selectivity of the adaptive mechanism. Our data suggest a new model in which the VOR operates as a series of parallel, temporal frequency channels, each of which has an independently adjustable gain element. Adaptive changes were produced by oscillating monkeys sinusoidally at a single temporal frequency (0.2 or 2.0 Hz) in visual conditions that cause either increases (toward two) or decreases (toward zero) in VOR gain. When tested in darkness at the adapting frequency, the VOR showed large changes in gain and little or no change in phase. When tested at frequencies other than the adapting frequency, the VOR showed less pronounced changes in gain and unexpected changes in phase. The phase changes were orderly but depended in a complex way on adapting frequency, testing frequency, and VOR gain. We have tested the channels concept by calculating the response properties of a mathematical model that processed its inputs in parallel pathways. The model reproduced our data when we assumed that the vestibular primary afferents were distributed in an orderly way to parallel brain channels that had differing dynamics: vestibular inputs with more phase lead projected to higher frequency channels, which themselves had faster dynamics than their low frequency counterparts. Such an organization, when regulated by an adaptive controller that can selectively alter the gain of one channel, could play a key role in establishing and maintaining the frequency-independent performance seen in the adult VOR.
前庭眼反射（VOR）受到长期适应性调节，以在头部运动期间最小化视网膜图像滑动；正常情况下，这一过程使VOR增益（眼速度除以头速度）接近1.0。通常认为适应性机制是一个单一的纯增益元件，尽管该系统的一些特性（例如，VOR增益的频率选择性变化）表明它一定更为复杂。我们现在报告关于适应性机制频率选择性的新观察结果。我们的数据提示了一种新模型，其中VOR作为一系列并行的时间频率通道起作用，每个通道都有一个独立可调的增益元件。在导致VOR增益增加（趋向于2）或减少（趋向于零）的视觉条件下，通过以单一时间频率（0.2或2.0 Hz）对猴子进行正弦摆动来产生适应性变化。当在适应频率的黑暗环境中进行测试时，VOR显示出增益的大幅变化以及相位很少或没有变化。当在不同于适应频率的频率下进行测试时，VOR显示出增益变化不那么明显以及相位出现意外变化。相位变化是有序的，但以一种复杂的方式取决于适应频率、测试频率和VOR增益。我们通过计算一个在并行通路中处理其输入的数学模型的响应特性来测试通道概念。当我们假设前庭初级传入神经以有序方式分布到具有不同动力学的并行脑通道时，该模型再现了我们的数据：具有更多相位超前的前庭输入投射到更高频率通道，这些通道本身的动力学比低频对应通道更快。这样一种组织，当由一个能够选择性改变一个通道增益的适应性控制器调节时，可能在建立和维持成年VOR中所见的频率独立性能方面发挥关键作用。
