The role of the hippocampus in retaining relational information across short delays: The importance of memory load
The role of the hippocampus in retaining relational information across short delays: The importance of memory load
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DOI：
10.1101/lm.2010711
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发表时间：
2011-05-01
影响因子：
2
通讯作者：
Squire, Larry R.
中科院分区：
文献类型：
--
作者：
Jeneson, Annette;Mauldin, Kristin N.;Squire, Larry R.
海马损伤的患者有时会在短短几秒钟的延迟中记忆信息。如何理解这些缺陷？一种可能性是，某些类型的信息的保留在很大程度上依赖于海马体，无论保留间隔如何，也无论任务是否依赖于工作记忆或长期记忆。或者，只有当任务涉及的记忆负荷大到足以超过工作记忆容量时，记忆力的保持才可能依赖于海马体。为了探索这些可能性，我们评估了海马损伤患者在两项任务上的表现，这两项任务需要在短暂的延迟内保留相同的场景中的对象信息。这些任务对记忆力有不同的要求。在一项使用连续识别格式的任务中，参与者需要尝试记住多达九个场景，即使在研究场景和相应的测试场景之间没有任何场景。患者在这种情况下受损。在第二个任务中，使用传统的学习测试格式，参与者需要记住一个场景，每次3或14秒。在这个过程中，患者在3秒延迟后表现与对照组一样好，但在14秒延迟后受损。我们认为，保留的对象在场景中的信息是依赖于海马体，只有当工作记忆是不足以支持性能（因为记忆负荷高或保留间隔长）。在这些情况下，表现至少部分取决于长期记忆。
Patients with hippocampal damage are sometimes impaired at remembering information across delays as short as a few seconds. How are these impairments to be understood? One possibility is that retention of some kinds of information is critically dependent on the hippocampus, regardless of the retention interval and regardless of whether the task depends on working memory or long-term memory. Alternatively, retention may be dependent on the hippocampus only when the task involves a memory load large enough to exceed working memory capacity. To explore these possibilities, we assessed the performance of patients with hippocampal lesions on two tasks requiring retention of the same object-in-scene information across a brief delay. The tasks placed different demands on memory. In one task, which used a continuous recognition format, participants needed to try to hold up to nine scenes in mind, even when no scene intervened between the study scene and the corresponding test scene. Patients were impaired in this condition. In a second task, using a conventional study-test format, participants needed to hold in mind only one scene at a time for either 3 or 14 sec. With this procedure, patients performed as well as controls after a 3-sec delay but were impaired after a 14-sec delay. We suggest that retention of object-in-scene information is dependent on the hippocampus only when working memory is insufficient to support performance (because memory load is high or the retention interval is long). In these circumstances performance depends, at least in part, on long-term memory.