Proklova Daria, Kaiser Daniel, Peelen Marius V
University of Trento.
J Cogn Neurosci. 2016 May;28(5):680-92. doi: 10.1162/jocn_a_00924. Epub 2016 Jan 14.
Objects belonging to different categories evoke reliably different fMRI activity patterns in human occipitotemporal cortex, with the most prominent distinction being that between animate and inanimate objects. An unresolved question is whether these categorical distinctions reflect category-associated visual properties of objects or whether they genuinely reflect object category. Here, we addressed this question by measuring fMRI responses to animate and inanimate objects that were closely matched for shape and low-level visual features. Univariate contrasts revealed animate- and inanimate-preferring regions in ventral and lateral temporal cortex even for individually matched object pairs (e.g., snake-rope). Using representational similarity analysis, we mapped out brain regions in which the pairwise dissimilarity of multivoxel activity patterns (neural dissimilarity) was predicted by the objects' pairwise visual dissimilarity and/or their categorical dissimilarity. Visual dissimilarity was measured as the time it took participants to find a unique target among identical distractors in three visual search experiments, where we separately quantified overall dissimilarity, outline dissimilarity, and texture dissimilarity. All three visual dissimilarity structures predicted neural dissimilarity in regions of visual cortex. Interestingly, these analyses revealed several clusters in which categorical dissimilarity predicted neural dissimilarity after regressing out visual dissimilarity. Together, these results suggest that the animate-inanimate organization of human visual cortex is not fully explained by differences in the characteristic shape or texture properties of animals and inanimate objects. Instead, representations of visual object properties and object category may coexist in more anterior parts of the visual system.
属于不同类别的物体在人类枕颞叶皮层中会可靠地引发不同的功能磁共振成像（fMRI）活动模式，最显著的区别在于有生命物体和无生命物体之间。一个尚未解决的问题是，这些类别区分是反映了物体与类别相关的视觉属性，还是真的反映了物体类别。在这里，我们通过测量对形状和低级视觉特征紧密匹配的有生命和无生命物体的fMRI反应来解决这个问题。单变量对比揭示了腹侧和外侧颞叶皮层中存在偏好有生命和无生命物体的区域，即使是针对个体匹配的物体对（例如，蛇-绳子）。使用表征相似性分析，我们绘制出了大脑区域，其中多体素活动模式的成对差异（神经差异）由物体的成对视觉差异和/或它们的类别差异预测。视觉差异通过参与者在三个视觉搜索实验中在相同干扰物中找到唯一目标所需的时间来衡量，在这些实验中，我们分别量化了整体差异、轮廓差异和纹理差异。所有三种视觉差异结构都预测了视觉皮层区域的神经差异。有趣的是，这些分析揭示了几个簇，在去除视觉差异后，类别差异预测了神经差异。总之，这些结果表明，人类视觉皮层的有生命-无生命组织不能完全由动物和无生命物体的特征形状或纹理属性差异来解释。相反，视觉物体属性和物体类别的表征可能共存于视觉系统更靠前的部分。
