Abstract：
Contextual features are integral to episodic memories; yet, we know little about context effects on pattern separation, a hippocampal function promoting orthogonalization of overlapping memory representations. Recent studies suggested that various extrahippocampal brain regions support pattern separation; however, the specific role of the parahippocampal cortex-a region involved in context representation-in pattern separation has not yet been studied. Here, we investigated the contribution of the parahippocampal cortex (specifically, the parahippocampal place area) to context reinstatement effects on mnemonic discrimination, using functional magnetic resonance imaging. During scanning, participants saw object images on unique context scenes, followed by a recognition task involving the repetitions of encoded objects or visually similar lures on either their original context or a lure context. Context reinstatement at retrieval improved item recognition but hindered mnemonic discrimination. Crucially, our region of interest analyses of the parahippocampal place area and an object-selective visual area, the lateral occipital cortex indicated that while during successful mnemonic decisions parahippocampal place area activity decreased for old contexts compared to lure contexts irrespective of object novelty, lateral occipital cortex activity differentiated between old and lure objects exclusively. These results imply that pattern separation of contextual and item-specific memory features may be differentially aided by scene and object-selective cortical areas.
摘要：
情境特征是情景记忆不可或缺的；然而，我们对上下文对模式分离的影响知之甚少，促进重叠记忆表征的正交化的海马功能。最近的研究表明，各种海马外脑区支持模式分离；然而，尚未研究海马旁皮层-一个参与上下文表征模式分离的区域的具体作用.这里,我们调查了海马旁皮层的贡献(特别是，海马旁区域)对记忆区分的上下文恢复效果，使用功能磁共振成像。在扫描过程中,参与者在独特的上下文场景中看到了物体图像，然后是识别任务，该任务涉及在其原始上下文或诱饵上下文上重复编码对象或视觉上相似的诱饵。检索时的上下文恢复改善了项目识别，但阻碍了记忆区分。至关重要的是，我们感兴趣的区域分析了海马旁位置区域和对象选择视觉区域，枕骨外侧皮层表明，在成功的记忆决定过程中，与引诱环境相比，旧环境下海马旁区域的活动减少，而与对象新颖性无关。枕骨外侧皮层活动仅在旧物体和诱饵物体之间区分。这些结果表明，场景和对象选择皮层区域可能会不同地帮助上下文和特定于项目的记忆特征的模式分离。
