Perrone John A, Krauzlis Richard J
The University of Waikato, Hamilton, New Zealand.
J Vis. 2008 Dec 18;8(14):24.1-14. doi: 10.1167/8.14.24.
The question as to how the visual motion generated during eye movements can be 'canceled' to prevent an apparent displacement of the external world has a long history. The most popular theories (R. W. Sperry, 1950; E. von Holst & H. Mittelstaedt, 1950) lack specifics concerning the neural mechanisms involved and their loci. Here we demonstrate that a form of vector subtraction can be implemented in a biologically plausible way using cosine distributions of activity from visual motion sensors and from an extraretinal source such as a pursuit signal. We show that the net result of applying an 'efference copy/corollary discharge signal' in the form of a cosine distribution is a motion signal that is equivalent to that produced by vector subtraction. This vector operation provides a means of 'canceling' the effect of eye movements. It enables the extraretinal generated image motion to be correctly removed from the combined retinal-extraretinal motion, even in cases where the two motions do not share the same direction. In contrast to the established theories (efference copy and corollary discharge), our new model makes specific testable predictions concerning the location (the MT-MST/VIP areas) and nature of the eye-rotation cancellation stage (neural-based vector subtraction).
关于眼球运动过程中产生的视觉运动如何被“抵消”以防止外部世界出现明显位移的问题由来已久。最流行的理论（R. W. 斯佩里，1950年；E. 冯·霍尔斯特和H. 米特尔施泰特，1950年）缺乏关于所涉及的神经机制及其位点的具体内容。在这里，我们证明了一种形式的矢量减法可以以生物学上合理的方式实现，即利用视觉运动传感器和诸如追踪信号等视网膜外来源的活动余弦分布。我们表明，以余弦分布形式应用“传出副本/推论放电信号”的净结果是一个与矢量减法产生的运动信号等效的运动信号。这种矢量运算提供了一种“抵消”眼球运动效果的方法。它能够将视网膜外产生的图像运动从视网膜 - 视网膜外的组合运动中正确去除，即使在两种运动方向不同的情况下也是如此。与已有的理论（传出副本和推论放电）相比，我们的新模型对眼球旋转抵消阶段的位置（MT-MST/VIP区域）和性质（基于神经的矢量减法）做出了具体的可测试预测。
