Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany; Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany; Berlin School of Mind and Brain, Berlin, Germany.
Department of Psychology, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, USA.
Neuroimage. 2019 Jul 1;194:12-24. doi: 10.1016/j.neuroimage.2019.03.031. Epub 2019 Mar 17.
The degree to which we perceive real-world objects as similar or dissimilar structures our perception and guides categorization behavior. Here, we investigated the neural representations enabling perceived similarity using behavioral judgments, fMRI and MEG. As different object dimensions co-occur and partly correlate, to understand the relationship between perceived similarity and brain activity it is necessary to assess the unique role of multiple object dimensions. We thus behaviorally assessed perceived object similarity in relation to shape, function, color and background. We then used representational similarity analyses to relate these behavioral judgments to brain activity. We observed a link between each object dimension and representations in visual cortex. These representations emerged rapidly within 200 ms of stimulus onset. Assessing the unique role of each object dimension revealed partly overlapping and distributed representations: while color-related representations distinctly preceded shape-related representations both in the processing hierarchy of the ventral visual pathway and in time, several dimensions were linked to high-level ventral visual cortex. Further analysis singled out the shape dimension as neither fully accounted for by supra-category membership, nor a deep neural network trained on object categorization. Together our results comprehensively characterize the relationship between perceived similarity of key object dimensions and neural activity.
我们对真实世界物体的感知程度，即相似或不同的结构，影响我们的感知，并指导分类行为。在这里，我们使用行为判断、fMRI 和 MEG 研究了使感知相似的神经表示。由于不同的物体维度共同出现并且部分相关，为了理解感知相似性和大脑活动之间的关系，有必要评估多个物体维度的独特作用。因此，我们在形状、功能、颜色和背景方面对物体的感知相似性进行了行为评估。然后，我们使用表示相似性分析将这些行为判断与大脑活动联系起来。我们观察到每个物体维度与视觉皮层中的表示之间存在联系。这些表示在刺激开始后 200 毫秒内迅速出现。评估每个物体维度的独特作用揭示了部分重叠和分布式的表示：虽然颜色相关的表示在腹侧视觉通路的处理层次结构和时间上明显先于形状相关的表示，但几个维度与高级腹侧视觉皮层有关。进一步的分析确定形状维度既不完全由超类别成员资格解释，也不由经过物体分类训练的深度神经网络解释。总之，我们的结果全面描述了关键物体维度的感知相似性与神经活动之间的关系。
