Hippocampal contributions to episodic encoding: Insights from relational and item-based learning
Hippocampal contributions to episodic encoding: Insights from relational and item-based learning
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DOI：
10.1152/jn.2002.88.2.982
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发表时间：
2002-08-01
影响因子：
2.5
通讯作者：
Wagner, AD
中科院分区：
文献类型：
--
作者：
Davachi, L;Wagner, AD
海马体和周围内侧颞叶皮质的完整性对情景记忆至关重要，海马体被认为支持关系或结构联想学习。本研究利用事件相关功能磁共振成像（fMRI）研究了特定的中颞叶结构在关系加工和基于项目的学习过程中的作用，以及这些结构在工作记忆中基于项目的刺激维持过程中的作用程度。fMRI显示，在两种语言编码条件下，海马体和底层皮质区域的参与情况，一种需要在工作记忆中以项目为基础维持单词三联体，另一种需要在每个单词三联体中形成项目间的联系。16名受试者在经历基于项目和关系处理试验时，使用快速事件相关功能磁共振成像设计进行扫描。为了检验学习过程中中颞叶结构的fMRI信号与受试者随后记忆刺激的能力（有效记忆形成的一种测量方法）之间的相关性，受试者在完成编码扫描后进行了是-否识别记忆测试。结果表明，在关系处理和基于项目的处理过程中，海马体都参与其中，关系处理导致海马体更大的反应。相比之下，在基于项目的加工过程中，内嗅回和海马旁回的参与是不同的，这为海马和海马旁结构之间的功能神经解剖学区别提供了强有力的证据。对后续记忆的神经相关分析表明，双侧海马的激活与有效记忆形成的行为测量可靠地相关，仅对那些以相关方式编码的刺激。综上所述，这些数据提供了证据，表明海马体在参与基于项目的工作记忆维持过程时，会以不同的方式将项目的关系绑定提供给一个综合记忆痕迹，从而使该经历可以在以后被记住。
The integrity of the hippocampus and surrounding medial-temporal cortices is critical for episodic memory, with the hippocampus being posited to support relational or configural associative learning. The present event-related functional magnetic resonance imaging (fMRI) study investigated the role of specific medial-temporal lobe structures in learning during relational and item-based processing, as well as the extent to which these structures are engaged during item-based maintenance of stimuli in working memory. fMRI indexed involvement of the hippocampus and underlying cortical regions during performance of two verbal encoding conditions, one that required item-based maintenance of word triplets in working memory and the other that entailed the formation of inter-item associations across the words in each triplet. Sixteen subjects were scanned using a rapid event-related fMRI design while they encountered the item-based and relational processing trials. To examine the correlation between fMRI signal in medial-temporal structures during learning and the subject's subsequent ability to remember the stimuli (a measure of effective memory formation), subjects were administered a yes-no recognition memory test following completion of the encoding scans. Results revealed that the hippocampus proper was engaged during both relational and item-based processing, with relational processing resulting in a greater hippocampal response. By contrast, entorhinal and parahippocampal gyri were differentially engaged during item-based processing, providing strong evidence for a functional neuroanatomic distinction between hippocampal and parahippocampal structures. Analysis of the neural correlates of subsequent memory revealed that activation in the bilateral hippocampus was reliably correlated with behavioral measures of effective memory formation only for those stimuli that were encoded in a relational manner. Taken together, these data provide evidence that the hippocampus, while engaged during item-based working memory maintenance, differentially subserves the relational binding of items into an integrated memory trace so that the experience can be later remembered.