Scene segmentation in early visual cortex during suppression of ventral stream regions
Scene segmentation in early visual cortex during suppression of ventral stream regions
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DOI：
10.1016/j.neuroimage.2016.11.024
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发表时间：
2017-02-01
期刊：
影响因子：
5.7
通讯作者：
Bartels, Andreas
中科院分区：
文献类型：
--
作者：
Grassi, Pablo R.;Zaretskaya, Natalia;Bartels, Andreas
越来越多的文献表明，早期视觉处理的反馈调制是普遍存在的，是皮质计算的核心。特别是具有高水平内容的刺激总是激活腹侧物体反应区域，已被证明会抑制早期视觉皮层。这种抑制通常在预测编码和腹侧区域反馈的框架中解释。在这里，我们研究了早期的视觉调制感知的完形错觉，以前已被证明是介导的背顶叶皮层，而不是由腹侧区域，没有激活。动态刺激由移动的点组成，这些点可以被感知为一个大的移动立方体的角落（整体完形），也可以被感知为局部移动元素的分布式集合。我们发现，知觉绑定到一个虚幻的完形的本地移动元素导致空间隔离的差异调制，VI和V2：表示虚幻的线条和前景增强，而诱导剂和背景被抑制。此外，相关性分析表明，不同的机制管理前和背景调制。我们的研究结果表明，运动诱导的完形知觉差异调制的腹侧流激活的情况下，早期的视觉皮层。
A growing body of literature suggests that feedback modulation of early visual processing is ubiquitous and central to cortical computation. In particular stimuli with high-level content that invariably activate ventral object responsive regions have been shown to suppress early visual cortex. This suppression was typically interpreted in the framework of predictive coding and feedback from ventral regions. Here we examined early visual modulation during perception of a bistable Gestalt illusion that has previously been shown to be mediated by dorsal parietal cortex rather than by ventral regions that were not activated. The bistable dynamic stimulus consisted of moving dots that could either be perceived as corners of a large moving cube (global Gestalt) or as distributed sets of locally moving elements. We found that perceptual binding of local moving elements into an illusory Gestalt led to spatially segregated differential modulations in both, VI and V2: representations of illusory lines and foreground were enhanced, while inducers and background were suppressed. Furthermore, correlation analyses suggest that distinct mechanisms govern fore-and background modulation. Our results demonstrate that motion-induced Gestalt perception differentially modulates early visual cortex in the absence of ventral stream activation.