Fixational instability and natural image statistics: implications for early visual representations.
Fixational instability and natural image statistics: implications for early visual representations.
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注视不稳定性和自然图像统计：对早期视觉表征的影响。
DOI：
10.1080/09548980500300507
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Casile,Antonino
中科院分区：
文献类型：
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作者：
Rucci,Michele;Casile,Antonino
在自然观看条件下，眼睛、头部和身体的微小运动会妨碍保持稳定的注视方向。众所周知，当刺激在视网膜上稳定几秒钟时，它们往往会褪色。然而，目前还不清楚视网膜图像的生理运动是否在短暂的自然视觉注视期间起到视觉目的。本研究探讨了注视不稳定性对视网膜视觉输入的统计和早期视觉系统神经活动结构的影响。我们发现，固定不稳定性引入了一个组成部分，在视网膜输入信号，在自然图像的存在下，缺乏空间相关性。该成分强烈影响LGN模型中的神经活动。即使模拟细胞的对比敏感度函数没有完全调整到平衡自然图像的幂律谱，它也能使细胞反应去相关。已经提出了在视觉系统的早期阶段的神经活动的去相关对于丢弃输入信号中的统计冗余是有益的。本研究的结果表明，固视不稳定性可能有助于建立有效的表征自然刺激。
Under natural viewing conditions, small movements of the eye, head and body prevent the maintenance of a steady direction of gaze. It is known that stimuli tend to fade when they are stabilized on the retina for several seconds. However, it is unclear whether the physiological motion of the retinal image serves a visual purpose during the brief periods of natural visual fixation. This study examines the impact of fixational instability on the statistics of the visual input to the retina and on the structure of neural activity in the early visual system. We show that fixational instability introduces a component in the retinal input signals that, in the presence of natural images, lacks spatial correlations. This component strongly influences neural activity in a model of the LGN. It decorrelates cell responses even if the contrast sensitivity functions of simulated cells are not perfectly tuned to counter-balance the power-law spectrum of natural images. A decorrelation of neural activity at the early stages of the visual system has been proposed to be beneficial for discarding statistical redundancies in the input signals. The results of this study suggest that fixational instability might contribute to the establishment of efficient representations of natural stimuli.