Department of Psychology, Center for Learning and Memory, and Institute for Neuroscience, The University of Texas at Austin, Austin, Texas 78712, USA.
J Neurosci. 2010 Nov 3;30(44):14676-84. doi: 10.1523/JNEUROSCI.3250-10.2010.
Episodic memory is characterized by rapid formation of new associations that bind information within individual episodes. A powerful aspect of episodic memory is the ability to flexibly apply and recombine information from past experience to guide new behavior. A critical question for memory research is how medial temporal lobe (MTL) and prefrontal cortex (PFC), regions implicated in rapid within-episode binding, further support cross-episode binding in service of mnemonic flexibility. We set to answer this question using an associative inference task in humans that required rapid binding of information across overlapping experiences (AB, BC) to enable successful transfer to novel test probes (AC). Within regions predicting subsequent associative memory for directly learned associations, encoding activation in MTL, including hippocampus and parahippocampal cortex, uniquely predicted success on novel transfer trials both within and across participants, consistent with an integrative encoding mechanism where overlapping experiences are linked into a combined representation during learning. In contrast, during retrieval, PFC activation predicted trial-by-trial transfer success while MTL predicted transfer performance across participants. Moreover, increased MTL-PFC coupling was observed during novel transfer trials compared with retrieval of directly learned associations. These findings suggest that inferential processes support transfer of rapidly acquired experiences to novel events during retrieval where multiple memories are recalled and flexibly recombined in service of successful behavior. Together, these results demonstrate distinct encoding and retrieval mechanisms that support mnemonic flexibility, revealing a unique role for MTL regions in cross-episode binding during encoding and engagement of interactive MTL-PFC processes during flexible transfer at test.
情景记忆的特点是快速形成新的联想，将个体情景中的信息联系起来。情景记忆的一个强大方面是能够灵活地应用和重新组合过去经验中的信息，以指导新的行为。记忆研究的一个关键问题是，内侧颞叶（MTL）和前额叶皮层（PFC）这两个与情景内绑定有关的区域，如何进一步支持跨情景绑定，以实现记忆灵活性。我们使用人类的联想推理任务来回答这个问题，该任务要求在重叠的经验（AB、BC）之间快速绑定信息，以成功转移到新的测试探针（AC）。在预测直接学习关联的后续联想记忆的区域中，MTL （包括海马体和海马旁回）的编码激活，独特地预测了参与者内和参与者间的新转移试验的成功，这与一种整合的编码机制一致，即在学习过程中，重叠的经验被链接成一个综合的表示。相比之下，在检索过程中，PFC 的激活预测了逐试转移的成功，而 MTL 则预测了参与者间的转移表现。此外，与直接学习关联的检索相比，在新的转移试验中观察到 MTL-PFC 耦合的增加。这些发现表明，推理过程支持在检索过程中快速获取的经验向新事件的转移，在检索过程中，多个记忆被召回并灵活地重新组合，以成功地进行行为。总之，这些结果表明，存在支持记忆灵活性的独特编码和检索机制，揭示了 MTL 区域在编码期间的跨情景绑定和在灵活转移时的交互 MTL-PFC 过程的参与中的独特作用。
