Hippocampal CA3 region predicts memory sequences: Accounting for the phase precession of place cells
Hippocampal CA3 region predicts memory sequences: Accounting for the phase precession of place cells
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DOI：
10.1101/lm.3.2-3.279
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发表时间：
1996-09-01
影响因子：
2
通讯作者：
Lisman, JE
中科院分区：
文献类型：
--
作者：
Jensen, O;Lisman, JE
海马记录显示，在同一θ振荡期间，不同位置的细胞在不同阶段放电，可能是在不同γ周期的峰值。当老鼠在给定细胞的位置场移动时，θ周期中的放电阶段逐渐推进。在本文中，我们试图确定是否最近开发的海马和皮层记忆功能的模型可以解释这个相位提前和其他属性的位置细胞。根据这种基于生理学的模型，CA 3网络存储关于在学习期间遍历的位置的序列的信息。在这里，我们表明，相位提前可以理解，如果它是假设海马是在回忆模式，操作时，动物已经熟悉的路径。在这种模式下，感官信息的当前位置触发回忆即将到来的5-6个地方（记忆）在路径中的一个记忆的速度每伽玛周期。该模型预测，平均相位提前将是一个伽马周期每θ周期，一个值在合理的协议与数据。该模型还正确地解释了（1）位置细胞的放电发生在类似于7 θ周期的事实（2）观察到位置细胞放电的相位更系统地取决于位置而不是时间;以及（3）已经熟悉的路径的遍历产生进一步修改（将单元的激发移动到路径中的较早位置）的事实。后来的发现表明，回忆以前存储的信息可以加强对该信息的记忆。在模型中，这是因为N-甲基-D-天冬氨酸通道在回忆中的新作用。该模型的普遍成功为海马体存储序列信息并在伽马频率回忆期间预测预期位置的想法提供了支持。
Hippocampal recordings show that different place cells fire at different phases during the same theta oscillation, probably at the peak of different gamma cycles. As the rat moves through the place field of a given cell, the phase of firing during the theta cycle advances progressively. In this paper we have sought to determine whether a recently developed model of hippocampal and cortical memory function can explain this phase advance and other properties of place cells. According to this physiologically based model, the CA3 network stores information about the sequence of places traversed during learning. Here we show that the phase advance can be understood if it is assumed that the hippocampus is in a recall mode that operates when the animal is already familiar with a path. in this mode, sensory information about the current position triggers recall of the upcoming 5-6 places (memories) in the path at a rate of one memory per gamma cycle. The model predicts that the average phase advance will be one gamma cycle per theta cycle, a value in reasonable agreement with the data. The model also correctly accounts for (1) the fact that the firing of a place cell occurs during similar to 7 theta cycles (on average) as the animal crosses the place field; (2) the observation that the phase of place cell firing depends more systematically on position than on time; and (3) the fact that traversal of an already familiar path produces further modifications (shifts the firing of a cell to an earlier position in the path). This later finding suggests that recall of previously stored information strengthens the memory of that information. In the model, this occurs because of a novel role of N-methyl-D-aspartate channels in recall. The general success of the model provides support for the idea that the hippocampus stores sequence information and makes predictions of expected positions during gamma-frequency recall.