A role for the hippocampus in encoding simulations of future events
A role for the hippocampus in encoding simulations of future events
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DOI：
10.1073/pnas.1105816108
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发表时间：
2011-08-16
影响因子：
11.1
通讯作者：
Addis, Donna Rose
中科院分区：
文献类型：
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作者：
Martin, Victoria C.;Schacter, Daniel L.;Addis, Donna Rose
海马体在想象未来中的作用引起了相当大的兴趣。相对于记忆中的过去事件，想象的未来事件观察到优先的右侧海马参与，海马损伤的患者在想象详细的未来事件时受损。然而，一些海马损伤的患者在想象时并没有受损，这表明在某些情况下海马可能不需要进行情景模拟。鉴于海马在记忆编码中的作用，与想象相关的海马活动可能反映了模拟的编码，而不是事件本身的构建。目前的功能（f）MRI研究探讨了这种可能性。参与者根据人物、地点和物体的线索想象未来的事件。扫描后的线索回忆测试探测记忆的细节集分类未来的事件，要么成功编码或没有。成功与不成功的编码事件的对比显示前和后右侧海马群。当想象的事件被成功编码时，前海马和后海马显示出共同的功能连接网络，包括海马旁回，内侧顶叶和扣带皮层，内侧前额叶皮层。然而，当编码不成功时，只有前海马体而不是后海马体表现出这种连接模式。这些发现表明，在未来的模拟过程中观察到的右海马活动可能反映了模拟到记忆的编码。这种功能对于构建连贯的场景并不是必不可少的，这可能解释了为什么一些海马损伤的患者仍然能够想象未来。
The role of the hippocampus in imagining the future has been of considerable interest. Preferential right hippocampal engagement is observed for imagined future events relative to remembered past events, and patients with hippocampal damage are impaired when imagining detailed future events. However, some patients with hippocampal damage are not impaired at imagining, suggesting that there are conditions in which the hippocampus may not be necessary for episodic simulation. Given the known hippocampal role in memory encoding, the hippocampal activity associated with imagining may reflect the encoding of simulations rather than event construction per se. The present functional (f)MRI study investigated this possibility. Participants imagined future events in response to person, place, and object cues. A postscan cued-recall test probing memory for detail sets classified future events as either successfully encoded or not. A contrast of successfully versus unsuccessfully encoded events revealed anterior and posterior right hippocampal clusters. When imagined events were successfully encoded, both anterior and posterior hippocampus showed common functional connectivity to a network including parahippocampal gyrus, medial parietal and cingulate cortex, and medial prefrontal cortex. However, when encoding was unsuccessful, only the anterior hippocampus, and not the posterior, exhibited this pattern of connectivity. These findings demonstrate that right hippocampal activity observed during future simulation may reflect the encoding of the simulations into memory. This function is not essential for constructing coherent scenarios and may explain why some patients with hippocampal damage are still able to imagine the future.