The Functional Organization of High-Level Visual Cortex Determines the Representation of Complex Visual Stimuli
The Functional Organization of High-Level Visual Cortex Determines the Representation of Complex Visual Stimuli
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DOI：
10.1523/jneurosci.0446
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发表时间：
2020-09-23
影响因子：
5.3
通讯作者：
Yovel, Galit
中科院分区：
文献类型：
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作者：
Kliger, Libi;Yovel, Galit
高级视觉皮层的一个标志是其相邻区域的功能组织，这些区域对单个类别（如面部、身体和物体）具有选择性。然而，视觉场景通常由多个类别组成。分类选择皮层如何表征如此复杂的刺激？先前的研究表明，多个刺激的表征可以用一个归一化机制来解释。在这里，我们建议，一个正常化机制，在相邻的类别选择性区域组成的皮层区域将产生一个表示的多类别刺激，不断变化的类别选择性皮层作为其组件的类别选择性的大小的函数。通过使用功能磁共振成像，我们可以检查类别选择性和沿着一个大的连续皮层区域的多类别刺激的表征之间的这种对应关系。为了测试这些预测，我们使用线性模型来拟合人类参与者（男女）对多类别刺激（例如，一个完整的人）基于对其单独呈现的成分刺激的响应（例如，脸或身体）。与我们的预测一致，高级视觉皮质中的皮质区对多类别刺激的反应沿着加权平均线以连续的方式变化，作为其类别选择性大小的函数。这是相关（脸+身体）和不相关（脸+衣柜）多类别对的情况。我们的结论是，相邻的类别选择区域的功能组织，可以使复杂的视觉场景，可以根据任务需求调制的更高层次的认知系统的动态和灵活的表示。
A hallmark of high-level visual cortex is its functional organization of neighboring areas that are selective for single catego-ries, such as faces, bodies, and objects. However, visual scenes are typically composed of multiple categories. How does a category-selective cortex represent such complex stimuli? Previous studies have shown that the representation of multiple stimuli can be explained by a normalization mechanism. Here we propose that a normalization mechanism that operates in a cortical region composed of neighboring category-selective areas would generate a representation of multi-category stimuli that varies continuously across a category-selective cortex as a function of the magnitude of category selectivity for its components. By using fMRI, we can examine this correspondence between category selectivity and the representation of multi -category stimuli along a large, continuous region of cortex. To test these predictions, we used a linear model to fit the fMRI response of human participants (both sexes) to a multi-category stimulus (e.g., a whole person) based on the response to its component stimuli presented in isolation (e.g., a face or a body). Consistent with our predictions, the response of cortical areas in high-level visual cortex to multi-category stimuli varies in a continuous manner along a weighted mean line, as a function of the magnitude of its category selectivity. This was the case for both related (face + body) and unrelated (face+wardrobe) multi-category pairs. We conclude that the functional organization of neighboring category-selective areas may enable a dynamic and flexible representation of complex visual scenes that can be modulated by higher-level cognitive systems according to task demands.