Mussap A J, Crassini B, Flanagan P R
School of Psychology, Deakin University, Burwood, Australia.
Vision Res. 1998 Jul;38(14):2087-98. doi: 10.1016/s0042-6989(97)00429-x.
In three experiments the direction of motion after-effect (MAE) is measured following adaptation to two gratings moving in different directions presented in alternation (component-induced MAEs: CMAEs), and to moving plaid patterns composed of superimposed pairs of these gratings (plaid-induced MAEs; PMAEs). These MAEs are compared to: (i) the vector sum direction of the component gratings; (ii) the IOC-predicted direction of the plaids; and (iii) the perceived direction of the plaids as reported by observers. Contrary to previous findings (Burke D, Wenderoth P. Vis Res 1993;33:351-9), directions of PMAEs are shown to approximate the vector sum direction of the components, whereas directions of CMAEs are shown to approximate the mean (unweighted) direction of the components. This difference is attributed to the activity, and adaptation, of an additional population of neurones whose stimulus), or a counterphase moving plaid (a combined Fourier and non-Fourier stimulus), rules out the possibility that the discrepancy between PMAE direction and actual plaid direction is due to the use of test stimuli that do not adequately reflect adaptation by the Fourier and non-Fourier components of the adapting plaids (HR, Ferrera VP, Yo C. Vis Neurosci 1992;9:79-97). Various explanations of this paradoxical result are discussed, including: (i) that MAEs produced by Fourier components out-weigh (and possibly even mask) MAEs produced by non-Fourier plaid components; (ii) PMAEs are influenced by adaptation of a population of component-selective neurones that do not contribute to plaid perception; and, (iii) PMAEs are influenced by component-specific adaptation effects that are weighted according to relative component sensitivity, rather than relative component speed (Pantle A. Vis Res 14;1974:1229-36). We review psychophysical and neurophysiological evidence consistent with these explanations.
在三个实验中，测量了在交替呈现两个沿不同方向移动的光栅（成分诱导运动后效：CMAEs）以及由这些光栅的叠加对组成的移动格子图案（格子诱导运动后效；PMAEs）后产生的运动后效（MAE）的方向。将这些MAEs与以下各项进行比较：（i）成分光栅的矢量和方向；（ii）IOC预测的格子方向；以及（iii）观察者报告的格子的感知方向。与先前的研究结果（Burke D，Wenderoth P. Vis Res 1993；33：351 - 9）相反，结果表明PMAEs的方向近似于成分的矢量和方向，而CMAEs的方向近似于成分的平均（未加权）方向。这种差异归因于另一群神经元的活动和适应，其刺激）或反相移动格子（一种组合的傅里叶和非傅里叶刺激）排除了PMAE方向与实际格子方向之间的差异是由于使用了不能充分反映适应格子的傅里叶和非傅里叶成分的测试刺激的可能性（HR，Ferrera VP，Yo C. Vis Neurosci 1992；9：79 - 97）。讨论了对这一矛盾结果的各种解释，包括：（i）傅里叶成分产生的MAEs超过（甚至可能掩盖）非傅里叶格子成分产生的MAEs；（ii）PMAEs受一群对格子感知无贡献的成分选择性神经元的适应影响；以及（iii）PMAEs受根据相对成分敏感性而非相对成分速度加权的成分特异性适应效应影响（Pantle A. Vis Res 14；1974：1229 - 36）。我们回顾了与这些解释一致的心理物理学和神经生理学证据。
