Department of Psychology and York Neuroimaging Centre, University of York, York, YO10 5DD, United Kingdom.
Sci Rep. 2017 May 26;7(1):2444. doi: 10.1038/s41598-017-02569-4.
High-level regions of the ventral visual pathway respond more to intact objects compared to scrambled objects. The aim of this study was to determine if this selectivity for objects emerges at an earlier stage of processing. Visual areas (V1-V3) were defined for each participant using retinotopic mapping. Participants then viewed intact and scrambled images from different object categories (bottle, chair, face, house, shoe) while neural responses were measured using fMRI. Our rationale for using scrambled images is that they contain the same low-level properties as the intact objects, but lack the higher-order combinations of features that are characteristic of natural images. Neural responses were higher for scrambled than intact images in all regions. However, the difference between intact and scrambled images was smaller in V3 compared to V1 and V2. Next, we measured the spatial patterns of response to intact and scrambled images from different object categories. We found higher within-category compared to between category correlations for both intact and scrambled images demonstrating distinct patterns of response. Spatial patterns of response were more distinct for intact compared to scrambled images in V3, but not in V1 or V2. These findings demonstrate the emergence of selectivity to natural images in V3.
腹侧视觉通路的高级区域对完整物体的反应比对打乱物体的反应更强烈。本研究的目的是确定这种对物体的选择性是否出现在处理的早期阶段。使用视网膜映射为每个参与者定义了视觉区域（V1-V3）。然后，参与者在 fMRI 测量神经反应的同时观看来自不同物体类别的完整和打乱图像（瓶子、椅子、脸、房子、鞋子）。我们使用打乱图像的理由是它们包含与完整物体相同的低级属性，但缺乏自然图像特征的更高阶组合。在所有区域，打乱图像的神经反应都高于完整图像。然而，与 V1 和 V2 相比，V3 中完整图像和打乱图像之间的差异较小。接下来，我们测量了来自不同物体类别的完整和打乱图像的反应的空间模式。我们发现，对于完整和打乱的图像，类别内的相关性都高于类别间的相关性，这表明了反应的独特模式。在 V3 中，与打乱图像相比，完整图像的反应空间模式更为独特，但在 V1 或 V2 中则不然。这些发现表明，在 V3 中出现了对自然图像的选择性。
