1] UCL Institute of Cognitive Neuroscience, 17 Queen Square, London WC1N 3AR, UK [2] UCL Institute of Neurology, Queen Square, London WC1 3BG, UK.
Nat Commun. 2015 Jul 2;6:7462. doi: 10.1038/ncomms8462.
Recollection is thought to be the hallmark of episodic memory. Here we provide evidence that the hippocampus binds together the diverse elements forming an event, allowing holistic recollection via pattern completion of all elements. Participants learn complex 'events' from multiple overlapping pairs of elements, and are tested on all pairwise associations. At encoding, element 'types' (locations, people and objects/animals) produce activation in distinct neocortical regions, while hippocampal activity predicts memory performance for all within-event pairs. When retrieving a pairwise association, neocortical activity corresponding to all event elements is reinstated, including those incidental to the task. Participant's degree of incidental reinstatement correlates with their hippocampal activity. Our results suggest that event elements, represented in distinct neocortical regions, are bound into coherent 'event engrams' in the hippocampus that enable episodic recollection--the re-experiencing or holistic retrieval of all aspects of an event--via a process of hippocampal pattern completion and neocortical reinstatement.
回忆被认为是情景记忆的标志。在这里，我们提供的证据表明，海马体将形成一个事件的各种元素结合在一起，通过所有元素的模式完成实现整体回忆。参与者从多个重叠的元素对中学习复杂的“事件”，并对所有成对的关联进行测试。在编码时，元素“类型”（位置、人和物体/动物）在不同的新皮质区域产生激活，而海马体活动预测所有事件内对的记忆表现。当检索成对的关联时，与所有事件元素相对应的新皮质活动被重新激活，包括与任务无关的元素。参与者的偶然重新激活程度与他们的海马体活动相关。我们的结果表明，在不同的新皮质区域中表示的事件元素被绑定到海马体中的连贯“事件记忆”中，从而通过海马体模式完成和新皮质重新激活的过程实现情景回忆——即对事件的所有方面的重新体验或整体检索。
