Zimmermann Eckart
Neuroscience Institute, National Research Council Pisa, Italy.
Front Syst Neurosci. 2015 Oct 19;9:132. doi: 10.3389/fnsys.2015.00132. eCollection 2015.
Visual objects presented briefly at the time of saccade onset appear compressed toward the saccade target. Compression strength depends on the presentation of a visual saccade target signal and is strongly reduced during the second saccade of a double-step saccade sequence (Zimmermann et al., 2014b). Here, I tested whether perisaccadic compression is linked to saccade planning by contrasting two double-step paradigms. In the same-direction double-step paradigm, subjects were required to perform two rightward 10° saccades successively. At various times around execution of the saccade sequence a probe dot was briefly flashed. Subjects had to localize the position of the probe dot after they had completed both saccades. I found compression of visual space only at the time of the first but not at the time of the second saccade. In the reverse-direction paradigm, subjects performed first a rightward 10° saccade followed by a leftward 10° saccade back to initial fixation. In this paradigm compression was found in similar magnitude during both saccades. Analysis of the saccade parameters did not reveal indications of saccade sequence preplanning in this paradigm. I therefore conclude that saccade planning, rather than saccade execution factors, is involved in perisaccadic compression.
在扫视开始时短暂呈现的视觉对象会朝着扫视目标方向被压缩。压缩强度取决于视觉扫视目标信号的呈现，并且在双步扫视序列的第二次扫视期间会大幅降低（齐默尔曼等人，2014b）。在此，我通过对比两种双步范式，测试了扫视周围的压缩是否与扫视计划相关。在同向双步范式中，要求受试者依次进行两次向右10°的扫视。在扫视序列执行前后的不同时间，一个探测点会短暂闪烁。受试者在完成两次扫视后必须定位探测点的位置。我发现仅在第一次扫视时存在视觉空间的压缩，而在第二次扫视时没有。在反向范式中，受试者先进行一次向右10°的扫视，然后向左10°扫视回到初始注视点。在这种范式中，两次扫视期间的压缩程度相似。对扫视参数的分析未发现该范式中扫视序列预先计划的迹象。因此，我得出结论，参与扫视周围压缩的是扫视计划，而非扫视执行因素。
