Object recognition relies on different transformations of the retinal input, carried out by the visual system, that range from local contrast to object shape and category. While some of those transformations are thought to occur at specific stages of the visual hierarchy, the features they represent are correlated (e.g., object shape and identity) and selectivity for the same feature overlaps in many brain regions. This may be explained either by collinearity across representations, or may instead reflect the coding of multiple dimensions by the same cortical population. Moreover, orthogonal and shared components may differently impact on distinctive stages of the visual hierarchy. We recorded functional MRI (fMRI) activity while participants passively attended to object images and employed a statistical approach that partitioned orthogonal and shared object representations to reveal their relative impact on brain processing. Orthogonal shape representations (silhouette, curvature and medial-axis) independently explained distinct and overlapping clusters of selectivity in occitotemporal (OTC) and parietal cortex. Moreover, we show that the relevance of shared representations linearly increases moving from posterior to anterior regions. These results indicate that the visual cortex encodes shared relations between different features in a topographic fashion and that object shape is encoded along different dimensions, each representing orthogonal features.

中文翻译：

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枕颞皮层的形状编码依赖于物体轮廓、曲率和中轴

物体识别依赖于视觉系统执行的视网膜输入的不同转换，范围从局部对比度到物体形状和类别。虽然其中一些转换被认为发生在视觉层次结构的特定阶段，但它们所代表的特征是相关的（例如，对象形状和身份），并且对同一特征的选择性在许多大脑区域重叠。这可以通过表示之间的共线性来解释，也可以通过相同的皮层群体反映多个维度的编码。此外，正交和共享组件可能对视觉层次结构的不同阶段产生不同的影响。我们记录了功能性 MRI (fMRI) 活动，而参与者则被动地关注对象图像，并采用一种统计方法来划分正交和共享对象表示，以揭示它们对大脑处理的相对影响。正交形状表示（轮廓、曲率和中轴）独立地解释了枕颞 (OTC) 和顶叶皮层中不同和重叠的选择性簇。此外，我们表明共享表示的相关性从后部区域到前部区域线性增加。这些结果表明，视觉皮层以地形方式对不同特征之间的共享关系进行编码，并且对象形状沿不同维度进行编码，每个维度代表正交特征。