Dentate gyrus granule cell firing patterns can induce mossy fiber long-term potentiation in vitro.
Dentate gyrus granule cell firing patterns can induce mossy fiber long-term potentiation in vitro.
复制标题
齿状回颗粒细胞放电模式可以在体外诱导苔藓纤维长期增强。
DOI：
10.1002/hipo.20815
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发表时间：
2011
期刊：
影响因子：
3.5
通讯作者：
Mellor,JackR
中科院分区：
文献类型：
--
作者：
Mistry,Rajen;Dennis,Siobhan;Frerking,Matthew;Mellor,JackR
海马颗粒细胞通过苔藓纤维突触将行为相关刺激的信息传递给CA3锥体细胞。这些突触表达一种形式的长时程增强（mfLTP），它是非赫布的，不需要NMDA受体。mfLTP被认为在突触前被诱导和表达，因此，mfLTP是否发生的主要决定因素是颗粒细胞中的活性。然而，目前还不清楚是否mfLTP可以诱导颗粒细胞在体内表现出的活动模式，如果是这样，什么样的背景下产生这些模式。为了解决这些问题，我们检查了大鼠在执行延迟非匹配样本（DNMS）任务期间体内记录的颗粒细胞活性，发现颗粒细胞表现出广泛的尖峰模式。小鼠体外切片实验表明，这些活性模式中的一些但不是全部可以诱导mfLTP。通过进一步定义海马脑片中mfLTP的活动阈值，我们发现mfLTP只能由以低平均放电频率高频率爆发放电的尖峰模式诱导。使用这些信息，我们然后筛选在DNMS任务期间的阈上活动爆发。在一个子集的细胞，阈上爆发优先发生在采样阶段的任务。如果阈上爆发发生后，在延迟阶段，任务的性能被打乱。我们的结论是，mfLTP可以诱导的颗粒细胞锋电位模式在记忆任务，和mfLTP诱导的时间可以预测任务的表现。© 2010 Wiley Periodicals，Inc.
Hippocampal granule cells transmit information about behaviorally‐relevant stimuli to CA3 pyramidal cells via mossy fiber synapses. These synapses express a form of long‐term potentiation (mfLTP) that is non‐Hebbian and does not require NMDA receptors. mfLTP is thought to be induced and expressed presynaptically, hence, the major determinant of whether mfLTP occurs is activity in the granule cells. However, it remains unclear whether mfLTP can be induced by activity patterns that granule cells exhibit in vivo, and—if so—what context generates these patterns. To address these issues, we examined granule cell activity from in vivo recordings from rats during performance of a delayed nonmatch‐to‐sample (DNMS) task and found that granule cells exhibit a wide range of spike patterns. In vitro slice experiments in mice demonstrated that some, but not all, of these patterns of activity could induce mfLTP. By further defining the activity thresholds for mfLTP in hippocampal slices, we found that mfLTP can only be induced by spike patterns that fire in high frequency bursts with a low average firing frequency. Using this information, we then screened for suprathreshold bursts of activity during the DNMS task. In a subset of cells, suprathreshold bursts occurred preferentially during the sampling phase of the task. If suprathreshold bursting took place later, during the delay phase, task performance was disrupted. We conclude that mfLTP can be induced by granule cell spike patterns during a memory task, and that the timing of mfLTP induction can predict task performance. © 2010 Wiley Periodicals, Inc.