Baker C L, Braddick O J
Vision Res. 1985;25(6):803-12. doi: 10.1016/0042-6989(85)90188-9.
The ability to report the direction of apparent motion when an array of random dots is displaced fails when the displacement exceeds a limiting value (dmax). We find that dmax increases rapidly with retinal eccentricity, in a manner different from spatial measures such as acuity which are believed to depend on the "magnification factor" of projection to area 17. The minimum displacement giving detectable motion (dmin) shows a shallower increase with eccentricity which is more compatible with the variation of cortical magnification. The dependence of apparent motion on the timing variables (exposure duration, inter-stimulus interval) changes negligibly with eccentricity. Consequently the dynamic range and the upper limit of detectable velocities increases greatly with eccentricity. The increase of dmax with eccentricity means that the perception of apparent motion will show an approximate invariance with display scale, even though dmax has a locally fixed value depending on receptive field structure.
当一组随机点阵列发生位移时，报告视在运动方向的能力在位移超过极限值（dmax）时会失效。我们发现，dmax随着视网膜偏心度迅速增加，其方式不同于诸如视敏度等空间测量指标，后者被认为取决于投射到17区的“放大因子”。产生可检测运动的最小位移（dmin）随偏心度的增加较为平缓，这与皮质放大率的变化更为相符。视在运动对视时变量（曝光持续时间、刺激间隔）的依赖性随偏心度的变化可忽略不计。因此，可检测速度的动态范围和上限随偏心度大幅增加。dmax随偏心度增加意味着，尽管dmax根据感受野结构具有局部固定值，但视在运动的感知将显示出与显示比例的近似不变性。
