Department of Vision and Cognition, The Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences, 1105 BA Amsterdam, The Netherlands.
J Neurosci. 2010 Sep 22;30(38):12745-58. doi: 10.1523/JNEUROSCI.6071-09.2010.
The perceptual salience and visibility of image elements is influenced by other elements in their vicinity. The perceptual effect of image elements on an adjacent target element depends on their relative orientation. Collinear flanking elements usually improve sensitivity for the target element, whereas orthogonal elements have a weaker effect. It is believed that the collinear flankers exert these effects through lateral interactions between neurons in the primary visual cortex (area V1), but the precise mechanisms underlying these contextual interactions remain unknown. Here, we directly examined this question by recording the effects of flankers on the responses of V1 neurons at parafoveal representations while monkeys performed a fixation task or a contrast detection task. We found, unexpectedly, that collinear flankers reduce the monkeys' perceptual sensitivity for a central target element. This behavioral effect was explained by a flanker-induced increase in the activity of V1 neurons in the absence of the central target stimulus, which reduced the amplitude of the target response. Our results indicate that the dominant effect of collinear flankers in parafoveal vision is suppression and suggest that these suppressive effects are caused by a decrease in the dynamic range of neurons coding the central target.
图像元素的感知显著性和可见性受到其附近其他元素的影响。图像元素对相邻目标元素的感知效果取决于它们的相对方向。共线侧翼元素通常会提高目标元素的敏感性，而正交元素的影响较弱。人们认为共线侧翼通过初级视觉皮层（V1 区）神经元之间的侧向外来相互作用产生这些影响，但这些上下文相互作用的确切机制仍不清楚。在这里，我们通过在猴子执行注视任务或对比度检测任务时记录侧翼对周边 V1 神经元反应的影响，直接研究了这个问题。我们出人意料地发现，共线侧翼会降低猴子对中央目标元素的感知敏感性。这种行为效应可以通过侧翼在没有中央目标刺激的情况下引起 V1 神经元活性的增加来解释，这会降低目标反应的幅度。我们的结果表明，在周边视觉中，共线侧翼的主要作用是抑制，这表明这些抑制作用是由编码中央目标的神经元动态范围减小引起的。
