Frost B J, Kaminer J J
Perception. 1975;4(1):51-8. doi: 10.1068/p040051.
Two experiments were conducted on the orientation anisotropy in which averaged visual evoked potentials (VEPs) were recorded from the occipital scalp. The first experiment confirmed the findings of Maffei and Campbell (1970) that obliquely oriented gratings alternated back and forth produced smaller-amplitude VEPs than when the gratings were oriented horizontally or vertically. Since no asymmetry was found in VEPs produced by a Julesz figure presented under identical conditions, it was concluded that direction of displacement could not have been contributing to the effect. In a second experiment head tilt of the subject was manipulated together with grating orientation and the results indicated that the orientation anisotropy is retinally rather than gravitationally referenced. It was concluded that the site of orientation constancy is located either at higher levels of the primary visual system or in the second visual system.
进行了两项关于方向各向异性的实验，其中从枕部头皮记录平均视觉诱发电位（VEP）。第一个实验证实了马费伊和坎贝尔（1970年）的发现，即来回交替倾斜取向的光栅比水平或垂直取向的光栅产生的VEP振幅更小。由于在相同条件下呈现的朱尔兹图形产生的VEP中未发现不对称性，因此得出结论，位移方向不可能是造成这种效应的原因。在第二个实验中，对受试者的头部倾斜与光栅取向一起进行了操纵，结果表明方向各向异性是视网膜而非重力参考的。得出的结论是，方向恒常性的部位要么位于初级视觉系统的较高水平，要么位于第二视觉系统中。
