Division of Sensory and Cognitive Information, National Institute for Physiological Sciences, Aichi 444-8585, Japan.
Department of Physiological Sciences, The Graduate University for Advanced Studies (SOKENDAI), Aichi 444-8585, Japan.
Cereb Cortex. 2017 Oct 1;27(10):4867-4880. doi: 10.1093/cercor/bhw282.
Complex shape and texture representations are known to be constructed from V1 along the ventral visual pathway through areas V2 and V4, but the underlying mechanism remains elusive. Recent study suggests that, for processing of textures, a collection of higher-order image statistics computed by combining V1-like filter responses serves as possible representations of textures both in V2 and V4. Here, to gain a clue for how these image statistics are processed in the extrastriate visual areas, we compared neuronal responses to textures in V2 and V4 of macaque monkeys. For individual neurons, we adaptively explored their preferred textures from among thousands of naturalistic textures and fitted the obtained responses using a combination of V1-like filter responses and higher-order statistics. We found that, while the selectivity for image statistics was largely comparable between V2 and V4, V4 showed slightly stronger sensitivity to the higher-order statistics than V2. Consistent with that finding, V4 responses were reduced to a greater extent than V2 responses when the monkeys were shown spectrally matched noise images that lacked higher-order statistics. We therefore suggest that there is a gradual development in representation of higher-order features along the ventral visual hierarchy.
复杂的形状和纹理表示形式已知是从 V1 沿着腹侧视觉通路构建的，经过 V2 和 V4 区域，但潜在的机制仍然难以捉摸。最近的研究表明，对于纹理的处理，通过组合 V1 样滤波器响应计算的一系列高阶图像统计信息可以作为 V2 和 V4 中纹理的可能表示形式。在这里，为了获得关于这些图像统计信息在外侧视觉区域中如何被处理的线索，我们比较了猕猴 V2 和 V4 中对纹理的神经元反应。对于单个神经元，我们自适应地从数千个自然纹理中探索它们的首选纹理，并使用 V1 样滤波器响应和高阶统计信息的组合来拟合获得的响应。我们发现，虽然 V2 和 V4 之间的图像统计信息选择性在很大程度上是可比的，但 V4 对高阶统计信息的敏感性略高于 V2。与该发现一致的是，当给猴子显示缺乏高阶统计信息的光谱匹配噪声图像时，V4 的反应比 V2 的反应降低得更大。因此，我们认为沿着腹侧视觉层次结构，高阶特征的表示形式逐渐发展。
