Eye Movement Targets Are Released from Visual Crowding
Eye Movement Targets Are Released from Visual Crowding
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DOI：
10.1523/jneurosci.4172-12.2013
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发表时间：
2013-02-13
影响因子：
5.3
通讯作者：
Remington, Roger W.
中科院分区：
文献类型：
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作者：
Harrison, William J.;Mattingley, Jason B.;Remington, Roger W.
当其他物体在附近时，我们的周边视觉识别物体的能力就会受损（Bouma, 1970）。这种现象被称为拥挤，通常与早期视觉处理中的相互作用有关，这种相互作用主要取决于视觉刺激的视网膜位置（Pelli, 2008； Pelli和Tillman， 2008）。在这里，我们测试了一种新的说法，即拥挤受到来自眼动准备过程中视网膜外信号的空间信息的影响。我们让人类观察者对拥挤的目标进行眼球运动，并在眼睛开始运动之前测量他们识别这些目标的能力。在向拥挤的物体扫视前50毫秒开始，我们发现不仅拥挤的程度急剧减少，而且拥挤发生的空间面积几乎减少了一半。尽管目标或侧翼刺激的视网膜位置没有改变，但这些拥挤的变化发生了。与拥挤只取决于视网膜信号的观点相反，我们的发现揭示了眼动信号的重要作用。眼动准备有效地增强了周边视觉在预期扫视目标处的物体识别能力。在视觉混乱的环境中进行主动搜索时，这些前皮层的变化可能会增强对周边视觉物体的识别。
Our ability to recognize objects in peripheral vision is impaired when other objects are nearby (Bouma, 1970). This phenomenon, known as crowding, is often linked to interactions in early visual processing that depend primarily on the retinal position of visual stimuli (Pelli, 2008; Pelli and Tillman, 2008). Here we tested a new account that suggests crowding is influenced by spatial information derived from an extraretinal signal involved in eye movement preparation. We had human observers execute eye movements to crowded targets and measured their ability to identify those targets just before the eyes began to move. Beginning similar to 50 ms before a saccade toward a crowded object, we found that not only was there a dramatic reduction in the magnitude of crowding, but the spatial area with in which crowding occurred was almost halved. These changes in crowding occurred despite no change in the retinal position of target or flanking stimuli. Contrary to the notion that crowding depends on retinal signals alone, our findings reveal an important role for eye movement signals. Eye movement preparation effectively enhances object discrimination in peripheral vision at the goal of the intended saccade. These presaccadic changes may enable enhanced recognition of visual objects in the periphery during active search of visually cluttered environments.