Contributions of intrinsic membrane dynamics to fast network oscillations with irregular neuronal discharges
Contributions of intrinsic membrane dynamics to fast network oscillations with irregular neuronal discharges
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DOI：
10.1152/jn.00510.2004
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发表时间：
2005-12-01
影响因子：
2.5
通讯作者：
Wang, XJ
中科院分区：
文献类型：
--
作者：
Geisler, C;Brunel, N;Wang, XJ
在局部场电位的快速振荡(40-100赫兹伽马波，100-200赫兹尖波纹波)期间，单个皮质神经元通常以远低于振荡频率的频率不规则地放电。最近的计算研究使用泄漏积分点火(LIF)神经元模型对这种快速振荡提供了数学描述。在这里，我们将这一理论框架扩展到更现实的Hodgkin-Huxley类型基于电导的神经元群体。在由化学突触随机和稀疏连接的GABA能神经元的嘈杂网络中，相干振荡出现的频率敏感地取决于单细胞膜的动力学。在受噪声正弦输入的单个细胞的振荡周期中，可以根据突触时间常数和首选的放电相位来解析地预测群体频率。后者在很大程度上取决于单个细胞的膜特性，并且可以在简化的指数积分与点火(EIF)神经元的背景下理解。我们发现，如果单细胞的有效输入电导很大，那么单细胞的相移足够小，就可以产生200赫兹的振荡。在由兴奋性锥体细胞和抑制性神经元组成的两种群网络中，反复兴奋可以降低或增加种群节律频率，这取决于神经元中兴奋性突触电流是在抑制性突触电流之后还是在抑制性突触电流之前。详细的单细胞特性对群体振荡有很大的影响，即使节律性不是源于起搏神经元，而是一种紧急的网络现象。
During fast oscillations in the local field potential ( 40 - 100 Hz gamma, 100 - 200 Hz sharp- wave ripples) single cortical neurons typically fire irregularly at rates that are much lower than the oscillation frequency. Recent computational studies have provided a mathematical description of such fast oscillations, using the leaky integrate- and- fire ( LIF) neuron model. Here, we extend this theoretical framework to populations of more realistic Hodgkin - Huxley- type conductance- based neurons. In a noisy network of GABAergic neurons that are connected randomly and sparsely by chemical synapses, coherent oscillations emerge with a frequency that depends sensitively on the single cell's membrane dynamics. The population frequency can be predicted analytically from the synaptic time constants and the preferred phase of discharge during the oscillatory cycle of a single cell subjected to noisy sinusoidal input. The latter depends significantly on the single cell's membrane properties and can be understood in the context of the simplified exponential integrate- and- fire ( EIF) neuron. We find that 200- Hz oscillations can be generated, provided the effective input conductance of single cells is large, so that the single neuron's phase shift is sufficiently small. In a two- population network of excitatory pyramidal cells and inhibitory neurons, recurrent excitation can either decrease or increase the population rhythmic frequency, depending on whether in a neuron the excitatory synaptic current follows or precedes the inhibitory synaptic current in an oscillatory cycle. Detailed single- cell properties have a substantial impact on population oscillations, even though rhythmicity does not originate from pacemaker neurons and is an emergent network phenomenon.