The emergence of tuning to global shape properties of radial frequency patterns in the ventral visual pathway
The emergence of tuning to global shape properties of radial frequency patterns in the ventral visual pathway
复制标题
腹侧视觉通路中径向频率模式的全局形状特性调谐的出现
DOI：
10.1101/2023.03.01.530430
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Lawrence S
中科院分区：
文献类型：
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作者：
Lawrence S
径向频率(RF)图案由圆半径的正弦调制产生，在RF较低时进行全局处理。因此，这些封闭的形状提供了一种有用的方法来询问人类视觉系统以进行曲率的全局处理。在V4和腹侧视觉通路的更多的前脸选择区域，RF模式比那些对放射状栅格的反应更大。这在很大程度上与在非人类灵长类动物上显示曲率处理出现在V4中的工作一致，但也明显地出现在腹侧视觉流的更高位置。我们没有将射频模式与其他刺激进行对比，而是以不同的频率呈现了它们，该方案允许8名人类参与者(3名女性)对射频进行调谐。我们发现在枕侧区域调谐到低RF，在V4也有一定程度的调谐。在一项对照实验中，我们在干扰局部轮廓的刺激中添加了高频波纹。对这些刺激的低频调谐仍然保留在腹侧视觉流中，强调了它在形状曲率的全局处理中的作用。然后，我们使用表征相似性分析来表明，在枕侧区域，神经表征与刺激相似性有关，当它是用一个捕捉刺激如何被感知的模型来计算的时候。因此，我们发现，形状曲率的整体加工早在V4就出现在腹侧视流中，但在枕侧区域被发现得更强烈，这些区域表现出与知觉很好地相关的反应和表征。当低水平刺激属性被考虑在内时，这样的调节出现在V4和LO2中，除了对象选择性区域LO之外。我们还记录了枕侧区域的整体形状属性的表现，这些表现被刺激之间的知觉差异的代理很好地预测。
Radial frequency (RF) patterns, created by sinusoidal modulations of a circle's radius, are processed globally when RF is low. These closed shapes therefore offer a useful way to interrogate the human visual system for global processing of curvature. RF patterns elicit greater responses than those to radial gratings in V4 and more anterior face-selective regions of the ventral visual pathway. This is largely consistent with work on nonhuman primates showing curvature processing emerges in V4, but is evident also higher up the ventral visual stream. Rather than contrasting RF patterns with other stimuli, we presented them at varied frequencies in a regimen that allowed tunings to RF to be derived from 8 human participants (3 female). We found tuning to low RF in lateral occipital areas and to some extent in V4. In a control experiment, we added a high-frequency ripple to the stimuli disrupting the local contour. Low-frequency tuning to these stimuli remained in the ventral visual stream, underscoring its role in global processing of shape curvature. We then used representational similarity analysis to show that, in lateral occipital areas, the neural representation was related to stimulus similarity, when it was computed with a model that captured how stimuli are perceived. We therefore show that global processing of shape curvature emerges in the ventral visual stream as early as V4, but is found more strongly in lateral occipital regions, which exhibit responses and representations that relate well to perception.SIGNIFICANCE STATEMENTWe show that tuning to low radial frequencies, known to engage global shape processing mechanisms, was localized to lateral occipital regions. When low-level stimulus properties were accounted for such tuning emerged in V4 and LO2 in addition to the object-selective region LO. We also documented representations of global shape properties in lateral occipital regions, and these representations were predicted well by a proxy of the perceptual difference between the stimuli.