Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom.
J Neurosci. 2011 May 18;31(20):7441-9. doi: 10.1523/JNEUROSCI.0267-11.2011.
The debate surrounding the function of the human posterior parahippocampal cortex (PHC) is currently dominated by two competing theories. The spatial layout hypothesis proposes that PHC processes information about the shape of space embodied in layout-defining scene features. The contextual association hypothesis rejects this notion, proposing instead that PHC responds to highly contextualized, but not necessarily spatial, stimuli. Here we present a novel concept that suggests PHC is primarily concerned with any representation that depicts three-dimensional local space, be it scenes or even single objects. Specifically, we identified space-defining (SD) and space-ambiguous (SA) single objects, where SD objects consistently evoke a strong sense of the surrounding space while SA objects do not, in the absence of any background, spatial layout, or context. We found that participants could easily identify and distinguish between SD and SA objects. This distinction was subsequently affirmed at a neural level, where visualizing or viewing single SD objects compared with SA objects engaged PHC, despite these single SD objects offering no information about the shape or layout of the space. Moreover, this PHC response was robust and not accounted for by other factors, including contextual associations. Instead, it was linked to intrinsic object properties, specifically a combination of perceived object size and portability. By showing that PHC is responsive to the awareness of surrounding local space suggests its role in scene processing is basic and fundamental, such that it is not dependent on complex scene properties such as geometric structure, scene schema, or contextual associations.
目前，关于人类后旁海马皮质（PHC）功能的争论主要由两种相互竞争的理论主导。空间布局假说提出，PHC 处理体现于布局定义场景特征的空间形状的信息。语境关联假说拒绝了这一观点，而是提出 PHC 对高度语境化但不一定是空间化的刺激做出反应。在这里，我们提出了一个新的概念，即 PHC 主要关注任何描绘三维局部空间的表示形式，无论是场景还是单个物体。具体来说，我们确定了空间定义（SD）和空间模糊（SA）的单个物体，其中 SD 物体始终强烈唤起周围空间的感觉，而 SA 物体在没有任何背景、空间布局或语境的情况下则不会。我们发现参与者可以轻松识别和区分 SD 和 SA 物体。这种区别随后在神经水平上得到了证实，在那里，与 SA 物体相比，可视化或观看单个 SD 物体会激活 PHC，尽管这些单个 SD 物体没有提供关于空间形状或布局的信息。此外，这种 PHC 反应是稳健的，不受其他因素的影响，包括语境关联。相反，它与物体的固有属性有关，特别是感知物体大小和便携性的组合。通过表明 PHC 对周围局部空间的意识有反应，这表明其在场景处理中的作用是基本和基础的，因此它不依赖于复杂的场景属性，如几何结构、场景图或语境关联。
