Category-Specificity in the Human Medial Temporal Lobe Cortex
Category-Specificity in the Human Medial Temporal Lobe Cortex
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DOI：
10.1002/hipo.20515
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发表时间：
2009-01-01
期刊：
影响因子：
3.5
通讯作者：
Davachi, L.
中科院分区：
文献类型：
--
作者：
Litman, L.;Awipi, T.;Davachi, L.
内侧颞叶皮层（MTLC）在新皮质关联区和海马之间的界面上占据关键位置。研究表明，MTLC包含不同的功能区域，其中鼻周皮层（PRc）优先支持物体加工，海马后旁皮层（PHc）优先支持空间信息编码。通过测量BOLD对物体、场景和其他刺激类别的不同反应，我们发现在前PRc对物体的反应和后PHc对场景刺激的反应之间存在双重分离。此外，为了了解这种双重分离背后的反应特征，采用了一种基于ROI的解剖方法。我们没有看到任何证据表明在假定的场景优先和物体优先的MTLC区域之间存在明显的边界。相反，场景优先反应在MTLC前区依次呈分级线性下降，直到PRc前区出现物体优先反应，尽管物体在海马旁回的前后范围产生高于基线的反应。其他刺激类别，如面孔和文字，要么导致少数受限区域（面孔）的激活高于基线，要么根本没有（文字）。因此，海马旁回的不同区域是对物体和场景的相对反应，而不仅仅是对任何一类的高于基线的反应。这种模式提出了一种可能性，即PHc后部和PRc前部位于由整个MTLC长度支持的单个组织连续体的两端。(C) 2008 Wiley-Liss, Inc。
The medial temporal lobe cortex (MTLC) occupies a pivotal position at the interface between neocortical association areas and the hippocampus. It has been suggested that the MTLC contains functionally distinct regions, with perirhinal cortex (PRc) preferentially supporting object processing and posterior parahippocampal cortex (PHc) preferentially supporting encoding of spatial information. Measuring differential BOLD responsiveness to objects, scenes, and other stimulus categories, we find a double dissociation between an anterior PRc response to objects and a posterior PHc response to scene stimuli. Furthermore, an anatomical ROI based approach was undertaken in an effort to understand the response profile underlying this double dissociation. We did not see any evidence for a sharp border between putatively distinct scene-preferential and object-preferential MTLC regions. Instead, scene-preferential responsiveness was noted to drop off in a graded, linear fashion in successively anterior MTLC regions until object-preferential responsiveness emerged in anterior PRc, although objects produced above baseline responses across the anterior-posterior extent of the parahippocampal gyrus. Other stimulus categories, such as faces and words, led to above baseline activation in either a few confined regions (faces) or none at all (words). Thus, what differentiated regions along the parahippocampal gryus was the relative response to objects and scenes, not simply above baseline responses to either category. This pattern raises the possibility that posterior PHc, and anterior PRc are situated at the ends of a single organizational continuum supported by the entire length of MTLC. (C) 2008 Wiley-Liss, Inc.