Flegal Kristin E, Marín-Gutiérrez Alejandro, Ragland J Daniel, Ranganath Charan
University of California, Davis.
J Cogn Neurosci. 2014 Aug;26(8):1694-704. doi: 10.1162/jocn_a_00587. Epub 2014 Feb 24.
Episodic memory is associated with the encoding and retrieval of context information and with a subjective sense of reexperiencing past events. The neural correlates of episodic retrieval have been extensively studied using fMRI, leading to the identification of a "general recollection network" including medial temporal, parietal, and prefrontal regions. However, in these studies, it is difficult to disentangle the effects of context retrieval from recollection. In this study, we used fMRI to determine the extent to which the recruitment of regions in the recollection network is contingent on context reinstatement. Participants were scanned during a cued recognition test for target words from encoded sentences. Studied target words were preceded by either a cue word studied in the same sentence (thus congruent with encoding context) or a cue word studied in a different sentence (thus incongruent with encoding context). Converging fMRI results from independently defined ROIs and whole-brain analysis showed regional specificity in the recollection network. Activity in hippocampus and parahippocampal cortex was specifically increased during successful retrieval following congruent context cues, whereas parietal and prefrontal components of the general recollection network were associated with confident retrieval irrespective of contextual congruency. Our findings implicate medial temporal regions in the retrieval of semantic context, contributing to, but dissociable from, recollective experience.
情景记忆与情境信息的编码和提取以及对过去事件的重新体验的主观感受相关。使用功能磁共振成像（fMRI）对情景提取的神经关联进行了广泛研究，从而确定了一个“一般回忆网络”，包括内侧颞叶、顶叶和前额叶区域。然而，在这些研究中，很难将情境提取的影响与回忆区分开来。在本研究中，我们使用功能磁共振成像来确定回忆网络中各区域的激活程度在多大程度上取决于情境恢复。在对编码句子中的目标词进行线索识别测试期间，对参与者进行扫描。所研究的目标词之前要么是在同一句子中研究过的线索词（因此与编码情境一致），要么是在不同句子中研究过的线索词（因此与编码情境不一致）。来自独立定义的感兴趣区域（ROI）和全脑分析的功能磁共振成像结果趋同，显示了回忆网络中的区域特异性。在与情境一致的线索提示后成功检索期间，海马体和海马旁皮质的活动特别增加，而一般回忆网络的顶叶和前额叶成分与自信检索相关，与情境一致性无关。我们的研究结果表明内侧颞叶区域参与语义情境的检索，这对回忆体验有贡献，但与之可分离。
