Dual multiple-scale processing for motion in the human visual system
Dual multiple-scale processing for motion in the human visual system
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DOI：
10.1016/s0042-6989(97)00092-8
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发表时间：
1997-10-01
期刊：
影响因子：
1.8
通讯作者：
Edwards, M
中科院分区：
文献类型：
--
作者：
Nishida, S;Ledgeway, T;Edwards, M
许多心理物理和生理学研究表明，一阶和二阶运动信号至少最初是由独立的通路处理的，这两条通路都由多个运动检测通道组成，每一个通道都被狭隘地调谐到不同的空间尺度(空间频率)，然而，人类视觉中辅助一阶和二阶运动感知的机制的确切数量和性质仍然存在争议和推测。我们试图通过进行选择性适应实验来澄清这一问题，在选择性适应实验中，在适应运动之前和之后测量用于识别一阶(亮度定义的)和二阶(对比度定义的)漂移光栅的刺激运动方向的调制深度阈值，系统地操纵适应和测试刺激的漂移方向、空间频率和刺激类型(一阶或二阶)，当适应和测试刺激都是一阶栅格或两个二阶栅格时，发现方向识别阈值的稳健上升，重要的是，这些后效既表现出方向选择性，又表现出空间频率选择性，一阶和二阶栅格之间的交叉适应效应有时也被观察到，但非常微弱，并且不具有空间频率选择性，这些发现直接支持了人类视觉系统中一阶和二阶运动的多尺度处理的存在，并提供了额外的证据，表明这两种运动最初是由独立的通路处理的，(C)1997 Elsevier Science Ltd.。
A number of psychophysical and physiological studies have suggested that first-and second-order motion signals are processed, at least initially, by independent pathways, and that the two pathways both consist of multiple motion-detecting channels that are each narrowly tuned to a different spatial scale (spatial frequency), However, the precise number and nature of the mechanisms that subserve first-and second-order motion perception in human vision remain both controversial and speculative. We sought to clarify this issue by conducting selective adaptation experiments, in which modulation-depth thresholds for identifying the direction of stimulus motion of first-order (luminance-defined) and second-order (contrast-defined) drifting gratings were measured both prior to and following adaptation to motion, The drift direction, spatial frequency and stimulus type (either first-or second-order) of the adaptation and test stimuli were systematically manipulated, When the adaptation and test stimuli were either both first-order gratings or both second-order gratings, robust elevations of direction-identification thresholds were found and, importantly, these aftereffects exhibited both direction-selectivity and spatial-frequency selectivity, Cross-over-adaptation effects between first-and second-order gratings were also sometimes observed, but were very weak and not spatial-frequency selective, These findings give direct support for the existence of multiple-scale processing for first-and second-order motion in the human visual system and provide additional evidence that the two varieties of motion are initially processed by independent pathways, (C) 1997 Elsevier Science Ltd.