Theoretical assessment of the function of the hippocampus has suggested that given certain physiological constraints at both the neuronal and cortical level, the hippocampus is best suited to associate discontiguous items that occur in different temporal or spatial positions. Conceptually, “discontiguous” refers to events that are to be associated with one another but do not temporally or spatially overlap. However, given that humans can actively maintain information “online” by rehearsing it, even when the information is no longer being presented to the sensory system, the right way to experimentally define “discontiguity” is still a question. Does it refer to a “gap” in the presentation of information (temporal discontiguity) or to an “interruption” of the active maintenance of working memory (WM) information (functional discontiguity)? To assess this, participants were imaged by functional magnetic resonance imaging (fMRI) when making judgments on whether two words were semantically related or not. In contrast with recognition memory that can be carried out through perceptual familiarity heuristics, judgments on semantic relatedness can only be accomplished through associative processing. To assess this experimentally, two words are either (1) presented at the same time (Event AB) or (2) one after the other with an unfilled, cross-viewing delay (Event A_B) (the uninterrupted discontiguity) or (3) presented one after the other, between which participants are required to perform a calculation task (Event A#B) (the interrupted discontiguity). Results of event-related fMRI analysis revealed that relative to Event AB, Event A_B was not associated with more hippocampal activity, whereas Event A#B was. The direct contrast of Event A#B relative to Event A_B also revealed significant hippocampal and parahippocampal activity. This result implied that functional discontiguity (the interruption of online maintenance of the inputted information) could be more apt at engaging the function of the hippocampus.

中文翻译：

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海马体在弥合功能性和时间性不连续性方面的功能

海马体功能的理论评估表明，考虑到神经元和皮质水平的某些生理限制，海马体最适合关联出现在不同时间或空间位置的不连续项目。从概念上讲，“不连续”是指彼此关联但在时间或空间上不重叠的事件。然而，鉴于人类可以通过排练来主动保持信息“在线”，即使信息不再呈现给感官系统，实验定义“不连续性”的正确方法仍然是一个问题。它是指信息呈现中的“差距”（时间不连续性）还是工作记忆（WM）信息的主动维护“中断”（功能性不连续性）？为了评估这一点，参与者在判断两个词是否在语义上相关时通过功能磁共振成像 (fMRI) 进行成像。与可以通过知觉熟悉启发式进行的识别记忆相比，对语义相关性的判断只能通过联想处理来完成。为了通过实验评估这一点，两个词要么 (1) 同时出现 (事件 AB) 要么 (2) 一个接一个地出现，具有未填充的交叉查看延迟（事件 A_B）（不间断的不连续性）或（3）一个接一个地呈现，在哪些参与者之间需要执行计算任务（事件 A#B）（中断的不连续性）。事件相关 fMRI 分析结果显示，相对于事件 AB，事件 A_B 与更多的海马活动无关，而事件 A#B 相关。事件 A#B 相对于事件 A_B 的直接对比也揭示了显着的海马和海马旁活动。这一结果意味着功能不连续（输入信息的在线维护中断）可能更容易发挥海马体的功能。事件 A#B 相对于事件 A_B 的直接对比也揭示了显着的海马和海马旁活动。这一结果意味着功能不连续（输入信息的在线维护中断）可能更容易发挥海马体的功能。事件 A#B 相对于事件 A_B 的直接对比也揭示了显着的海马和海马旁活动。这一结果意味着功能不连续（输入信息的在线维护中断）可能更容易发挥海马体的功能。