Khan Aarlenne Z, Blohm Gunnar, Pisella Laure, Munoz Douglas P
School of Optometry, University of Montreal, Room 260-25, 3744 Jean Brilliant, Montreal, QC, H3T 1P1, Canada.
Centre for Neuroscience Studies and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
Eur J Neurosci. 2015 Jun;41(12):1624-34. doi: 10.1111/ejn.12923. Epub 2015 May 13.
As we have limited processing abilities with respect to the plethora of visual information entering our brain, spatial selection mechanisms are crucial. These mechanisms result in both enhancing processing at a location of interest and in suppressing processing at other locations; together, they enable successful further processing of locations of interest. It has been suggested that saccade planning modulates these spatial selection mechanisms; however, the precise influence of saccades on the distribution of spatial resources underlying selection remains unclear. To this end, we compared discrimination performance at different locations (six) within a work space during different saccade tasks. We used visual discrimination performance as a behavioral measure of enhancement and suppression at the different locations. A total of 14 participants performed a dual discrimination/saccade countermanding task, which allowed us to specifically isolate the consequences of saccade execution. When a saccade was executed, discrimination performance at the cued location was never better than when fixation was maintained, suggesting that saccade execution did not enhance processing at a location more than knowing the likelihood of its appearance. However, discrimination was consistently lower at distractor (uncued) locations in all cases where a saccade was executed compared with when fixation was maintained. Based on these results, we suggest that saccade execution specifically suppresses distractor locations, whereas attention shifts (with or without an accompanying saccade) are involved in enhancing perceptual processing at the goal location.
由于我们处理涌入大脑的大量视觉信息的能力有限，空间选择机制至关重要。这些机制既能增强对感兴趣位置的处理，又能抑制其他位置的处理；它们共同作用，使对感兴趣位置的进一步处理得以成功进行。有人提出扫视计划会调节这些空间选择机制；然而，扫视对选择背后的空间资源分配的确切影响仍不清楚。为此，我们比较了在不同扫视任务期间工作空间内不同位置（六个）的辨别性能。我们将视觉辨别性能用作不同位置增强和抑制的行为指标。共有14名参与者执行了双重辨别/扫视取消任务，这使我们能够具体分离扫视执行的后果。当执行扫视时，提示位置的辨别性能从未比保持注视时更好，这表明扫视执行并没有比知道其出现的可能性更能增强对某个位置的处理。然而，与保持注视相比，在所有执行扫视的情况下，干扰物（未提示）位置的辨别始终更低。基于这些结果，我们认为扫视执行会特异性地抑制干扰物位置，而注意力转移（无论是否伴有扫视）则参与增强目标位置的感知处理。
