Revisiting the role of spike afterhyperpolarization and spike threshold in motoneuron current-frequency gain.
Revisiting the role of spike afterhyperpolarization and spike threshold in motoneuron current-frequency gain.
复制标题
重新审视超极化后的尖峰和尖峰阈值在运动神经元电流频率增益中的作用。
DOI：
10.1152/jn.01195.2011
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发表时间：
2012
影响因子：
2.5
通讯作者：
Mitchell,CassieS
中科院分区：
文献类型：
--
作者：
Lee,RobertH;Mitchell,CassieS
突触或注入输入电平与放电率之间的关系是表征神经元输入输出动力学的重要指标。在这项研究中，我们研究了两个长期持有的，但从未验证过的假设，在“后超极化的代数求和”理论，它解释了放电率如何随输入（通常称为输入电流频率调制或“F-I增益”）而变化。在理论中，后超极化本身，沿着尖峰阈值，被假定为常数。也就是说，尽管它们是理论中的中心概念，但它们不包括在任何反馈回路中，在反馈回路中，它们既可以影响放电率，也可以被放电率影响。我们进行了细胞内记录脊髓运动神经元在成年猫，以确定是否F-I增益与后超极化和/或尖峰阈值。我们观察到后超极化确实出现在F-I增益机制环之外，因此最初的假设成立。然而，所提出的实验证据表明，尖峰阈值似乎是在循环中。也就是说，与输入相关的尖峰阈值变化与F-I增益相关。我们提出了一个扩展的原始理论，它解释了F-I增益的实验相关性。
The relationship between synaptic or injecting input level and firing rate is an important metric to characterize neuron input-output dynamics. In this study, we examine two long-held, but never validated, assumptions in the “algebraic summation of afterhyperpolarization” theory, which explains how firing rate varies with input (typically referred to as input current-frequency modulation or “F-I gain”). In the theory, the afterhyperpolarizations themselves, along with spike threshold, were assumed constant. That is, whereas they were central concepts in the theory, they were not included in any feedback loops, wherein they could both affect and be affected by firing rate. We performed intracellular recordings from spinal motoneurons in the adult cat to determine whether F-I gain correlates with the afterhyperpolarization and/or spike threshold. We observe that the afterhyperpolarization does indeed appear to be out of the F-I gain mechanism loop, and thus that original assumption holds. However, the presented experimental evidence indicates that the spike threshold appears to be in the loop. That is, spike threshold variation associated with input correlates with F-I gain. We present an extension to the original theory, which explains the F-I gain experimental correlations.