Finlayson Nonie J, Zhang Xiaoli, Golomb Julie D
Department of Psychology, Center for Cognitive & Brain Sciences, The Ohio State University, Columbus, OH 43210, USA.
Department of Psychology, Center for Cognitive & Brain Sciences, The Ohio State University, Columbus, OH 43210, USA.
Neuroimage. 2017 Feb 15;147:507-516. doi: 10.1016/j.neuroimage.2016.12.039. Epub 2016 Dec 29.
Visual information is initially represented as 2D images on the retina, but our brains are able to transform this input to perceive our rich 3D environment. While many studies have explored 2D spatial representations or depth perception in isolation, it remains unknown if or how these processes interact in human visual cortex. Here we used functional MRI and multi-voxel pattern analysis to investigate the relationship between 2D location and position-in-depth information. We stimulated different 3D locations in a blocked design: each location was defined by horizontal, vertical, and depth position. Participants remained fixated at the center of the screen while passively viewing the peripheral stimuli with red/green anaglyph glasses. Our results revealed a widespread, systematic transition throughout visual cortex. As expected, 2D location information (horizontal and vertical) could be strongly decoded in early visual areas, with reduced decoding higher along the visual hierarchy, consistent with known changes in receptive field sizes. Critically, we found that the decoding of position-in-depth information tracked inversely with the 2D location pattern, with the magnitude of depth decoding gradually increasing from intermediate to higher visual and category regions. Representations of 2D location information became increasingly location-tolerant in later areas, where depth information was also tolerant to changes in 2D location. We propose that spatial representations gradually transition from 2D-dominant to balanced 3D (2D and depth) along the visual hierarchy.
视觉信息最初在视网膜上以二维图像的形式呈现，但我们的大脑能够转换这种输入，以感知丰富的三维环境。虽然许多研究单独探讨了二维空间表征或深度感知，但这些过程在人类视觉皮层中是否相互作用以及如何相互作用仍不清楚。在这里，我们使用功能磁共振成像和多体素模式分析来研究二维位置和深度位置信息之间的关系。我们在一个组块设计中刺激不同的三维位置：每个位置由水平、垂直和深度位置定义。参与者保持注视屏幕中心，同时通过红/绿立体眼镜被动观看外周刺激。我们的结果揭示了整个视觉皮层中广泛而系统的转变。正如预期的那样，二维位置信息（水平和垂直）在早期视觉区域能够被强烈解码，随着视觉层级的升高解码能力降低，这与已知的感受野大小变化一致。至关重要的是，我们发现深度位置信息的解码与二维位置模式呈反向追踪，深度解码的幅度从中间视觉区域到高级视觉和类别区域逐渐增加。二维位置信息的表征在后期区域对位置的容忍度越来越高，在这些区域深度信息对二维位置的变化也具有容忍度。我们提出，空间表征沿着视觉层级从以二维为主逐渐转变为平衡的三维（二维和深度）。
