Directional Tuning of Phase Precession Properties in the Hippocampus.
Directional Tuning of Phase Precession Properties in the Hippocampus.
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DOI：
10.1523/jneurosci.1569-21.2021
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发表时间：
2022-03-16
期刊：
影响因子：
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通讯作者：
Leibold C
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文献类型：
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作者：
Yiu YH;Leutgeb JK;Leibold C
海马体中的跑步方向是由位置场活动的速率调制编码的，但也由称为θ序列的尖峰时间相关性编码。然而，到目前为止，尚未探索方向性的编码率和方向性的地方字段的相关性是否相关，因此，方向性的信息是如何编码在角ammonis的性质仍然没有得到解决。在这里，使用先前发表的数据集，其中包含在CA 1，CA 2和CA 3子区域的大鼠海马位置细胞的尖峰活动在自由觅食的雄性Long-Evans大鼠在2D环境中，我们发现，率和尖峰定时代码相关。与位置场的优选发射速率方向相反，尖峰更可能经历θ相位进动，因此更强烈地影响配对相关性。此外，我们还确定了场对的一个子集，其theta相关性是固有的，因为当运行方向相反时，它们保持相同的激发顺序。这两种效应都与θ相位分布的差异有关，并且在CA 3中比在CA 1中更突出。因此，我们假设，内在尖峰是最突出的定向调制的感觉电机驱动海马放电率是最小的，这表明，外在和内在的序列有助于相位进动作为两个不同的机制。一方面，海马theta序列被认为反映了动物的运行轨迹，连接了过去和未来的位置。另一方面，序列已经被提出来反映丰富的，递归的海马连接，与以前的轨迹的记忆，甚至经验无关的前结构。这样的内在序列本质上是一维的，并且不能容易地与二维中的运行轨迹相协调，因为位置场可以在多个一维路径上接近。在这篇文章中，我们解剖相位进动沿着不同的方向在所有海马子区，并发现，CA 3特别是显示了高水平的方向无关的相关性，这是不一致的概念，代表运行轨迹。这些内在的相关性与以后的尖峰相位。
Running direction in the hippocampus is encoded by rate modulations of place field activity but also by spike timing correlations known as theta sequences. Whether directional rate codes and the directionality of place field correlations are related, however, has so far not been explored, and therefore the nature of how directional information is encoded in the cornu ammonis remains unresolved. Here, using a previously published dataset that contains the spike activity of rat hippocampal place cells in the CA1, CA2, and CA3 subregions during free foraging of male Long-Evans rats in a 2D environment, we found that rate and spike timing codes are related. Opposite to a preferred firing rate direction of a place field, spikes are more likely to undergo theta phase precession and, hence, more strongly affect paired correlations. Furthermore, we identified a subset of field pairs whose theta correlations are intrinsic in that they maintain the same firing order when the running direction is reversed. Both effects are associated with differences in theta phase distributions and are more prominent in CA3 than in CA1. We thus hypothesize that intrinsic spiking is most prominent when the directionally modulated sensory-motor drive of hippocampal firing rates is minimal, suggesting that extrinsic and intrinsic sequences contribute to phase precession as two distinct mechanisms. SIGNIFICANCE STATEMENT Hippocampal theta sequences, on the one hand, are thought to reflect the running trajectory of an animal, connecting past and future locations. On the other hand, sequences have been proposed to reflect the rich, recursive hippocampal connectivity, related to memories of previous trajectories or even to experience-independent prestructure. Such intrinsic sequences are inherently one dimensional and cannot be easily reconciled with running trajectories in two dimensions as place fields can be approached on multiple one-dimensional paths. In this article, we dissect phase precession along different directions in all hippocampal subareas and find that CA3 in particular shows a high level of direction-independent correlations that are inconsistent with the notion of representing running trajectories. These intrinsic correlations are associated with later spike phases.