Miniature eye movements enhance fine spatial detail
Miniature eye movements enhance fine spatial detail
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DOI：
10.1038/nature05866
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发表时间：
2007-06-14
期刊：
影响因子：
64.8
通讯作者：
Santini, Fabrizio
中科院分区：
文献类型：
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作者：
Rucci, Michele;Iovin, Ramon;Santini, Fabrizio
我们的眼睛一直在运动。即使在视觉注视期间，小的眼球运动也会不断地抖动凝视的位置(1-4)。众所周知，当在实验室中消除视网膜图像运动时，视觉感觉往往会褪色(5-9)。然而，长期以来，人们一直在争论，在自然观看的过程中，凝视的眼球运动是否除了防止视觉场景褪色之外还有功能(10-17)。在这项研究中，我们分析了人类凝视眼球运动对被噪声掩盖的栅格辨别的影响，噪声具有与自然图像相似的功率谱。使用一种新的视网膜图像稳定方法(18)，我们选择性地消除了通常在视觉注视的扫视间隔期间发生的视网膜图像的运动。在这里，我们表明，凝视眼球运动提高了对高空间频率刺激的辨别能力，但不能提高低空间频率刺激的辨别能力。这种改善源于注视眼球运动在视觉输入到视网膜时引入的时间调制，强调刺激的高空间频率谐波。在以低空间频率为主的自然视觉世界中，凝视眼球运动似乎构成了一种有效的采样策略，视觉系统通过这种策略增强了对空间细节的处理。
Our eyes are constantly in motion. Even during visual fixation, small eye movements continually jitter the location of gaze(1-4). It is known that visual percepts tend to fade when retinal image motion is eliminated in the laboratory(5-9). However, it has long been debated whether, during natural viewing, fixational eye movements have functions in addition to preventing the visual scene from fading(10-17). In this study, we analysed the influence in humans of fixational eye movements on the discrimination of gratings masked by noise that has a power spectrum similar to that of natural images. Using a new method of retinal image stabilization(18), we selectively eliminated the motion of the retinal image that normally occurs during the intersaccadic intervals of visual fixation. Here we show that fixational eye movements improve discrimination of high spatial frequency stimuli, but not of low spatial frequency stimuli. This improvement originates from the temporal modulations introduced by fixational eye movements in the visual input to the retina, which emphasize the high spatial frequency harmonics of the stimulus. In a natural visual world dominated by low spatial frequencies, fixational eye movements appear to constitute an effective sampling strategy by which the visual system enhances the processing of spatial detail.