Temporal Memory Is Shaped by Encoding Stability and Intervening Item Reactivation
Temporal Memory Is Shaped by Encoding Stability and Intervening Item Reactivation
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DOI：
10.1523/jneurosci.2535-14.2014
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发表时间：
2014-10-15
影响因子：
5.3
通讯作者：
Davachi, Lila
中科院分区：
文献类型：
--
作者：
DuBrow, Sarah;Davachi, Lila
要理解先前的经验，需要记住事件在时间上展开的顺序。先前的研究表明海马体和内侧颞叶皮层参与了与个体事件相关的时间信息的记忆。然而，在编码和检索跨扩展序列的时间信息所涉及的过程是相对知之甚少。在这里，我们使用功能磁共振成像在编码和检索的扩展序列，以测试特定的预测类型的信息用于解决时间顺序和海马体在这个过程中的作用。参与者研究了名人面孔和常见物体的图像序列，然后进行了近因辨别测试。感兴趣的主要条件是成对的项目，已经提出了三个干预项目，其中一半包括干预类别转移。在编码过程中，海马模式的相似性，在干预项目与随后的成功顺序记忆。为了测试关联检索的证据，我们训练了一个分类器来区分与人脸和物体相关的编码模式，并在近因歧视期间将分类器应用于fMRI模式。我们发现的证据表明，干预项目的类别内容重新激活近因判断，这与海马编码检索相似性。后续的行为启动实验揭示了额外的证据干预项目恢复时间顺序判断。恢复没有根据项目是否发生在一个单一的上下文或跨上下文边界的差异。因此，这些数据表明，由海马介导的项目间关联编码和检索有助于时间顺序记忆。
Making sense of previous experience requires remembering the order in which events unfolded in time. Prior work has implicated the hippocampus and medial temporal lobe cortex in memory for temporal information associated with individual episodes. However, the processes involved in encoding and retrieving temporal information across extended sequences is relatively poorly understood. Here we used fMRI during the encoding and retrieval of extended sequences to test specific predictions about the type of information used to resolve temporal order and the role of the hippocampus in this process. Participants studied sequences of images of celebrity faces and common objects followed by a recency discrimination test. The main conditions of interest were pairs of items that had been presented with three intervening items, half of which included an intervening category shift. During encoding, hippocampal pattern similarity across intervening items was associated with subsequent successful order memory. To test for evidence of associative retrieval, we trained a classifier to discriminate encoding patterns associated with faces versus objects and applied the classifier on fMRI patterns during recency discrimination. We found evidence that the category content of intervening items was reactivated during recency judgments, and this was related to hippocampal encoding-retrieval similarity. A follow-up behavioral priming experiment revealed additional evidence for intervening item reinstatement during temporal order judgments. Reinstatement did not differ according to whether the items occurred within a single context or across context boundaries. Thus, these data suggest that inter-item associative encoding and retrieval mediated by the hippocampus contribute to temporal order memory.