Massendari Delphine, Lisi Matteo, Collins Thérèse, Cavanagh Patrick
Laboratoire Psychologie de la Perception, CNRS UMR 8248, Université Paris Descartes , Paris , France.
Centre for Applied Vision Research, City University of London , London , United Kingdom.
J Neurophysiol. 2018 Jan 1;119(1):62-72. doi: 10.1152/jn.00229.2017. Epub 2017 Sep 27.
The double-drift stimulus (a drifting Gabor with orthogonal internal motion) generates a large discrepancy between its physical and perceived path. Surprisingly, saccades directed to the double-drift stimulus land along the physical, and not perceived, path (Lisi M, Cavanagh P. Curr Biol 25: 2535-2540, 2015). We asked whether memory-guided saccades exhibited the same dissociation from perception. Participants were asked to keep their gaze centered on a fixation dot while the double-drift stimulus moved back and forth on a linear path in the periphery. The offset of the fixation was the go signal to make a saccade to the target. In the visually guided saccade condition, the Gabor kept moving on its trajectory after the go signal but was removed once the saccade began. In the memory conditions, the Gabor disappeared before or at the same time as the go-signal (0- to 1,000-ms delay) and participants made a saccade to its remembered location. The results showed that visually guided saccades again targeted the physical rather than the perceived location. However, memory saccades, even with 0-ms delay, had landing positions shifted toward the perceived location. Our result shows that memory- and visually guided saccades are based on different spatial information. NEW & NOTEWORTHY We compared the effect of a perceptual illusion on two types of saccades, visually guided vs. memory-guided saccades, and found that whereas visually guided saccades were almost unaffected by the perceptual illusion, memory-guided saccades exhibited a strong effect of the illusion. Our result is the first evidence in the literature to show that visually and memory-guided saccades use different spatial representations.
双漂移刺激（一种具有正交内部运动的漂移伽柏光栅）在其物理路径和感知路径之间产生了很大差异。令人惊讶的是，指向双漂移刺激的扫视落在物理路径而非感知路径上（利西·M、卡瓦纳·P。《当代生物学》25: 2535 - 2540，2015）。我们询问记忆引导的扫视是否表现出与感知相同的分离。参与者被要求将目光集中在一个固定点上，同时双漂移刺激在外围沿直线路径来回移动。固定点的偏移是做出指向目标的扫视的启动信号。在视觉引导扫视条件下，伽柏光栅在启动信号后继续沿其轨迹移动，但一旦扫视开始就会消失。在记忆条件下，伽柏光栅在启动信号之前或同时消失（延迟0至1000毫秒），参与者向其记忆位置做出扫视。结果表明，视觉引导的扫视再次以物理位置而非感知位置为目标。然而，记忆扫视即使延迟为0毫秒，其着陆位置也会向感知位置偏移。我们的结果表明，记忆引导和视觉引导的扫视基于不同的空间信息。新进展与值得注意之处我们比较了一种感知错觉对两种扫视类型的影响，即视觉引导扫视与记忆引导扫视，发现视觉引导扫视几乎不受感知错觉的影响，而记忆引导扫视则表现出强烈的错觉效应。我们的结果是文献中首个表明视觉引导和记忆引导扫视使用不同空间表征的证据。
