Viskontas Indre V, Carr Valerie A, Engel Stephen A, Knowlton Barbara J
Department of Psychology, University of California, Los Angeles, California, USA.
Hippocampus. 2009 Mar;19(3):265-72. doi: 10.1002/hipo.20503.
Memories for certain events tend to linger in rich, vivid detail, and retrieval of these memories includes a sense of re-experiencing the details of the event. Most events, however, are not retained in any detailed way for more than a few days. According to one theory, the hippocampus plays a specific role in supporting episodic retrieval, that is, the re-experiencing of an event as part of one's personal past. This theory predicts that as episodic memories fade over time and are reduced to feelings of familiarity, activity in the hippocampus should no longer be associated with retrieval. We used high-resolution functional imaging to explore neural activity in medial temporal lobe subregions while participants performed a recognition task at both a short (10-min) and long (1-week) study-test delay. For each recognized item, subjects made "Remember/Know" judgments, allowing us to distinguish between items that were consistently episodic across the two tests and items that were initially episodic, but later became merely familiar. Our results demonstrate that activity in the subiculum is specifically associated with episodic recollection. Overall, recollected items were associated with higher activity in the subiculum than other items. For transiently recollected items, there was a decrease in subicular activity across the 1-week delay as memory faded from recollection to familiarity, whereas consistently recollected items were associated with enhanced subicular activity at both delays. These results provide evidence of a link between subicular activation and recollective experience.
某些事件的记忆往往会以丰富、生动的细节留存下来，而这些记忆的提取会让人有一种重新体验事件细节的感觉。然而，大多数事件并不会以任何详细的方式被保留超过几天。根据一种理论，海马体在支持情景记忆提取中发挥着特定作用，也就是说，将事件作为个人过去的一部分进行重新体验。该理论预测，随着情景记忆随着时间的推移而消退，并逐渐变为熟悉感，海马体中的活动应该不再与提取相关。我们使用高分辨率功能成像技术，在参与者分别于短（10分钟）和长（1周）的学习 - 测试间隔执行识别任务时，探究内侧颞叶亚区域的神经活动。对于每个被识别的项目，受试者做出“记得/知道”的判断，这使我们能够区分在两次测试中始终具有情景性的项目和最初具有情景性但后来仅变为熟悉的项目。我们的结果表明，下托中的活动与情景性回忆特别相关。总体而言，被回忆起的项目在下托中的活动比其他项目更高。对于短暂被回忆起的项目，随着记忆从回忆转变为熟悉，下托活动在1周的间隔中有所下降，而始终被回忆起的项目在两个间隔中都与下托活动增强相关。这些结果为下托激活与回忆体验之间的联系提供了证据。
