The hippocampus extrapolates beyond the view in scenes: An fMRI study of boundary extension
The hippocampus extrapolates beyond the view in scenes: An fMRI study of boundary extension
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DOI：
10.1016/j.cortex.2012.11.010
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发表时间：
2013-09-01
期刊：
影响因子：
3.6
通讯作者：
Maguire, Eleanor A.
中科院分区：
文献类型：
--
作者：
Chadwick, Martin J.;Mullally, Sinead L.;Maguire, Eleanor A.
边界延伸（BE）是一种普遍现象，人们记得看到的场景比实际输入的场景更多，因为他们推断出了原始刺激的边界。这种自动将场景嵌入到更广泛的背景中，支持我们对连续连贯的世界的体验，因此具有高度的适应性。BE虽然发生迅速，但被认为包括两个阶段。第一种方法涉及到场景在物理边界之外的积极外推，并且本质上是建设性的。第二阶段发生在检索阶段，在此阶段，超出原始场景边界的初始外推被随后的记忆错误所揭示。大脑中与最初的、至关重要的、视野之外的场景外推相关的区域从未被研究过。在这里，使用功能性磁共振成像（fMRI）和经典的BE范式，我们发现场景的外推在第一次观看场景时迅速发生，并且与海马体（HC）和海马体旁皮层（PHC）的参与有关。通过连通性分析，我们确定，特别是HC似乎驱动了BE效应，对PHC施加自上而下的影响，甚至远溯到早期视觉皮层（VC）的加工流。随后，这些皮质区域显示的活动概况跟踪了对场景的主观感知，而不是物理现实，从而反映了BE错误的行为表达。总之，我们的结果表明，HC参与了超出其物理边界的场景的主动外推。这些信息然后自动和快速地通过场景处理层次结构，早在早期的VC。这表明，场景的预期和构建是我们在线感知的一个普遍而重要的方面，而HC起着核心作用。(c) 2012 Elsevier Ltd.版权所有。
Boundary extension (BE) is a pervasive phenomenon whereby people remember seeing more of a scene than was present in the physical input, because they extrapolate beyond the borders of the original stimulus. This automatic embedding of a scene into a wider context supports our experience of a continuous and coherent world, and is therefore highly adaptive. BE, whilst occurring rapidly, is nevertheless thought to comprise two stages. The first involves the active extrapolation of the scene beyond its physical boundaries, and is constructive in nature. The second phase occurs at retrieval, where the initial extrapolation beyond the original scene borders is revealed by a subsequent memory error. The brain regions associated with the initial, and crucial, extrapolation of a scene beyond the view have never been investigated. Here, using functional MRI (fMRI) and a classic BE paradigm, we found that this extrapolation of scenes occurred rapidly around the time a scene was first viewed, and was associated with engagement of the hippocampus (HC) and parahippocampal cortex (PHC). Using connectivity analyses we determined that the HC in partictlar seemed to drive the BE effect, exerting top-down influence on PHC and indeed as far back down the processing stream as early visual cortex (VC). These cortical regions subsequently displayed activity profiles that tracked the trial-by-trial subjective perception of the scenes, rather than physical reality, thereby reflecting the behavioural expression of the BE error. Together our results show that the HC is involved in the active extrapolation of scenes beyond their physical borders. This information is then automatically and rapidly channelled through the scene processing hierarchy as far back as early VC. This suggests that the anticipation and construction of scenes is a pervasive and important aspect of our online perception, with the HC playing a central role. (c) 2012 Elsevier Ltd. All rights reserved.