Yang Y, Blake R
Department of Psychology, Vanderbilt University, Nashville, Tennessee 37240.
Nature. 1994 Oct 27;371(6500):793-6. doi: 10.1038/371793a0.
Neural events underlying perception of coherent motion are generally believed to be hierarchical: information about local motion is registered by spatio-temporal coincidence detectors whose outputs are cooperatively integrated at a subsequent stage. There is disagreement, however, concerning the spatial scale of the neural filters underlying these operations. According to one class of models, motion registration is initially accomplished in parallel at multiple spatial scales, with filters tuned to lower spatial frequencies responsive to larger motion displacements than filters tuned to higher frequencies. According to another scheme, motion analysis involves a single, broadly tuned spatial filter, with optimal displacement dependent on spacing of local elements. Here we use a masking procedure to measure the extent to which dynamic noise depicted at one spatial scale interferes with detection of coherent motion conveyed by image features at another spatial scale. Our results indicate that a single filter, broadly tuned for spatial frequency, is mediating detection of coherent motion. This finding dovetails with known physiological properties of neurons at an intermediate stage of motion processing.
人们普遍认为，连贯运动感知背后的神经活动是分层的：局部运动信息由时空重合探测器记录，其输出在后续阶段进行协同整合。然而，对于这些操作背后神经滤波器的空间尺度存在分歧。根据一类模型，运动记录最初在多个空间尺度上并行完成，与调谐到较高频率的滤波器相比，调谐到较低空间频率的滤波器对更大的运动位移有响应。根据另一种方案，运动分析涉及一个单一的、调谐范围广的空间滤波器，最佳位移取决于局部元素的间距。在这里，我们使用一种掩蔽程序来测量在一个空间尺度上描绘的动态噪声在多大程度上干扰了由另一个空间尺度上的图像特征传达的连贯运动的检测。我们的结果表明，一个对空间频率调谐范围广的单一滤波器在介导连贯运动的检测。这一发现与运动处理中间阶段神经元的已知生理特性相吻合。
