Lesions of the mammillary body region alter hippocampal movement signals and theta frequency: implications for path integration models.
Lesions of the mammillary body region alter hippocampal movement signals and theta frequency: implications for path integration models.
复制标题
乳头体区域的病变改变海马运动信号和 theta 频率：对路径整合模型的影响。
DOI：
10.1002/hipo.20474
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发表时间：
2008
期刊：
影响因子：
3.5
通讯作者：
Koester,Kate
中科院分区：
文献类型：
--
作者：
Sharp,PatriciaE;Koester,Kate
整个海马结构的细胞都参与处理空间信息。这些相同的细胞还显示出运动活动的影响，并且这些运动信号被认为对于这些细胞的路径整合能力至关重要。乳头区域的核对海马结构提供上行影响，并且与影响海马空间和 θ 信号有关。在这里，我们报告了乳头病变对几个海马亚区域运动相关信号的影响。我们首先发现，正如早期工作所预测的那样，这些病变导致细胞放电的 θ 调制频率降低约 1 Hz。根据最近的理论工作，这可能反过来会影响海马区域的大小。我们的数据并未证实对任何检查的海马区域的这一预测。其次，我们报告了海马细胞放电率和跑步速度之间关系的损伤效应。这些损伤导致海马体和下潜细胞的速率-速度函数的斜率和截距均降低。令人惊讶的是，下托细胞表现出相反的作用，从而增强了运动的兴奋性影响。路径整合理论预测路径整合发生的速度与该运动信号的强度有关。与这一预测非常一致的是，我们报告说，海马和下皮后细胞的乳头病变后，位置细胞信号的计时减慢，但相反，下皮细胞的信号计时加快。事实上，跨病变条件和大脑区域的位置信号的时序是通过单个线性函数预测的，该函数将时序与跑步速度信号的强度相关联。因此，这些数据为当前路径整合理论的某些方面提供了显着的支持，同时对这些相同理论的其他方面提出了挑战。 © 2008 Wiley-Liss, Inc.
Cells throughout the hippocampal formation are involved in processing spatial information. These same cells also show an influence of locomotor activity, and these movement signals are thought to be critical for the path integration abilities of these cells. Nuclei in the mammillary region provide ascending influences to the hippocampal formation and have been implicated in influencing both hippocampal spatial and theta signals. Here, we report the effects of mammillary lesions on movement‐related signals in several hippocampal subregions. We find first, as predicted by earlier work, these lesions cause an approximately 1 Hz reduction in the frequency of theta modulation of cell firing. According to recent theoretical work, this might, in turn, be expected to influence the size of hippocampal place fields. Our data do not confirm this prediction for any of the hippocampal regions examined. Second, we report lesion effects on the relationship between firing rate and running speed for the hippocampal cells. These lesions caused a reduction in both the slope and intercept of rate‐by‐speed functions for cells in the hippocampus and postsubiculum. Surprisingly, cells in subiculum showed an opposite effect, so that the excitatory influence of locomotion was enhanced. Path integration theories predict that the speed at which path integration occurs is related to the strength of this movement signal. In remarkable accordance with this prediction, we report that the timing of the place cell signals is slowed following mammillary lesions for hippocampal and postsubicular cells, but, in contrast, is speeded up for subicular cells. In fact, the timing for place signals across lesion condition and brain region is predicted by a single linear function which relates timing to the strength of the running speed signal. Thus, these data provide remarkable support for some aspects of current path integration theory, while posing a challenge for other aspects of these same theories. © 2008 Wiley‐Liss, Inc.