Epstein R, Kanwisher N
Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge 02139, USA.
Nature. 1998 Apr 9;392(6676):598-601. doi: 10.1038/33402.
Medial temporal brain regions such as the hippocampal formation and parahippocampal cortex have been generally implicated in navigation and visual memory. However, the specific function of each of these regions is not yet clear. Here we present evidence that a particular area within human parahippocampal cortex is involved in a critical component of navigation: perceiving the local visual environment. This region, which we name the 'parahippocampal place area' (PPA), responds selectively and automatically in functional magnetic resonance imaging (fMRI) to passively viewed scenes, but only weakly to single objects and not at all to faces. The critical factor for this activation appears to be the presence in the stimulus of information about the layout of local space. The response in the PPA to scenes with spatial layout but no discrete objects (empty rooms) is as strong as the response to complex meaningful scenes containing multiple objects (the same rooms furnished) and over twice as strong as the response to arrays of multiple objects without three-dimensional spatial context (the furniture from these rooms on a blank background). This response is reduced if the surfaces in the scene are rearranged so that they no longer define a coherent space. We propose that the PPA represents places by encoding the geometry of the local environment.
内侧颞叶脑区，如海马结构和海马旁皮质，通常与导航和视觉记忆有关。然而，这些区域中每个区域的具体功能尚不清楚。在此我们提供证据表明，人类海马旁皮质内的一个特定区域参与导航的一个关键组成部分：感知局部视觉环境。我们将这个区域命名为“海马旁位置区”（PPA），在功能磁共振成像（fMRI）中，它对被动观看的场景有选择性且自动的反应，但对单个物体反应微弱，对人脸则完全无反应。这种激活的关键因素似乎是刺激中存在关于局部空间布局的信息。PPA对有空间布局但无离散物体的场景（空房间）的反应与对包含多个物体的复杂有意义场景（同一房间摆放家具）的反应一样强烈，并且比对没有三维空间背景的多个物体阵列（这些房间的家具在空白背景上）的反应强两倍多。如果场景中的表面重新排列，使其不再定义一个连贯的空间，这种反应就会减弱。我们提出，PPA通过编码局部环境的几何形状来表征地点。
