Saidel W M, Lettvin J Y, MacNichol E F
Nature. 1983;304(5926):534-6. doi: 10.1038/304534a0.
Behavioural tests have demonstrated that cephalopods can discriminate light polarized in different planes, and the receptors have been localized by electrophysiological studies of the eye. Discrimination of the plane of polarization is a consequence of both the structure of the microvilli in the outer segments of the photoreceptors and the orientation of the photosensitive chromophore on these membranes. However, between the depolarizing receptor response resulting from photoreception and the behaviour of the animal, nothing is known about neuronal processing of polarized light by cephalopods. Here we show that some squid photoreceptors discriminate the plane of polarization within the spike train, and that any particular plane is seen as a variable intensity. Given the well known orthogonal orientation of microvilli in outer segments of adjacent photoreceptors and the physiological preference for one of two mutually perpendicular planes of polarization by single photoreceptors, we conclude that cephalopod vision is based on two complementary views of the world, each determined by the transformation of polarization-sensitive receptors into complementary intensity scales. A visual system based on this transformation would lead to enhanced contrast underwater and visualization of object details obscured by confounding highlights.
行为测试表明，头足类动物能够区分不同平面偏振的光，并且通过对眼睛的电生理研究已经确定了感受器的位置。偏振面的辨别是光感受器外段微绒毛结构以及这些膜上光敏发色团取向共同作用的结果。然而，在光感受引起的去极化受体反应与动物行为之间，关于头足类动物对偏振光的神经元处理过程我们一无所知。在这里，我们表明一些鱿鱼光感受器在动作电位序列中能够区分偏振面，并且任何特定平面都被视为可变强度。鉴于相邻光感受器外段微绒毛众所周知的正交取向以及单个光感受器对两个相互垂直偏振面之一的生理偏好，我们得出结论，头足类动物的视觉基于对世界的两种互补视角，每种视角都由偏振敏感受体转化为互补强度标度所决定。基于这种转化的视觉系统将增强水下对比度，并使被混淆高光掩盖的物体细节可视化。
