Nakayama K, Silverman G H, MacLeod D I, Mulligan J
Perception. 1985;14(2):225-38. doi: 10.1068/p140225.
The sensitivity of the visual system to motion of differentially moving random dots was measured. Two kinds of one-dimensional motion were compared: standing-wave patterns where dot movement amplitude varied as a sinusoidal function of position along the axis of dot movement (longitudinal or compressional waves) and patterns of motion where dot movement amplitude varied as a sinusoidal function orthogonal to the axis of motion (transverse or shearing waves). Spatial frequency, temporal frequency, and orientation of the motion were varied. The major finding was a much larger threshold rise for shear than for compression when motion spatial frequency increased beyond 1 cycle deg-1. Control experiments ruled out the extraneous cues of local luminance or local dot density. No conspicuous low spatial-frequency rise in thresholds for any type of differential motion was seen at the lowest spatial frequencies tested, and no difference was seen between horizontal and vertical motion. The results suggest that at the motion threshold spatial integration is greatest in a direction orthogonal to the direction of motion, a view consistent with elongated receptive fields most sensitive to motion orthogonal to their major axis.
测量了视觉系统对不同移动的随机点运动的敏感度。比较了两种一维运动：驻波模式，其中点的运动幅度沿点运动轴（纵向或压缩波）的位置呈正弦函数变化；以及运动模式，其中点的运动幅度垂直于运动轴呈正弦函数变化（横向或剪切波）。改变了运动的空间频率、时间频率和方向。主要发现是，当运动空间频率增加超过1周/度时，剪切运动的阈值上升比压缩运动大得多。对照实验排除了局部亮度或局部点密度等无关线索。在测试的最低空间频率下，未观察到任何类型的差异运动阈值有明显的低空间频率上升，水平运动和垂直运动之间也未观察到差异。结果表明，在运动阈值处，空间整合在垂直于运动方向的方向上最大，这一观点与对与其主轴垂直的运动最敏感的细长感受野一致。
