Passive normalization of synaptic integration influenced by dendritic architecture
Passive normalization of synaptic integration influenced by dendritic architecture
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DOI：
10.1152/jn.1999.82.6.3268
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发表时间：
1999-12-01
影响因子：
2.5
通讯作者：
Carnevale, NT
中科院分区：
文献类型：
--
作者：
Jaffe, DB;Carnevale, NT
我们研究了生物物理特性和神经元形态如何影响单个突触后电位（PSP）从突触输入到索马的传播。这种分析是基于这样的证据，即在大多数中枢神经元中，单个突触激活不会显著降低局部驱动力，因此每个突触近似地充当电流源。因此，PSP在整个树突树中的分布可以用传递阻抗（Z（c））来描述，其反映了施加在一个位置处的电流如何影响其他位置处的膜电位。我们通过四个方面的研究解决了这个问题，并发现了突触整合的神经元形态的新影响。首先，Z（c）被认为是根据双豌豆理论，并与树体电压传递。其次，利用等效圆柱模型比较了Z（c）和树体电压传递的空间分布。这些模拟表明，Z（c）受枝晶位置的影响小于电压传递。第三，使用基于五种不同神经元类型的形态重建的房室模型来计算Z（c）、输入阻抗（Z（N））和整个树突树的电压传递。对于所有神经元，Z（c）在高阶树突内的位置没有显著变化。此外，Z（c）在五种神经元类型中的三种（CA3中间神经元，CA3锥体神经元和齿状颗粒细胞）中相对独立于整个细胞的突触位置。这与Z（N）很不一样，Z（N）随着与索马的距离而增加，并导致电压传递的平行降低。第四，快兴奋性PSP（EPSP）的模拟与Z（c）的分析一致，EPSP峰值幅度变化
We examined how biophysical properties and neuronal morphology affect the propagation of individual postsynaptic potentials (PSPs) from synaptic inputs to the soma. This analysis is based on evidence that individual synaptic activations do not reduce local driving force significantly in most central neurons, so each synapse acts approximately as a current source. Therefore the spread of PSPs throughout a dendritic tree can be described in terms of transfer impedance (Z(c)), which reflects how a current applied at one location affects membrane potential at other locations. We addressed this topic through four lines of study and uncovered new implications of neuronal morphology for synaptic integration. First, Z(c) was considered in terms of two-pea theory and contrasted with dendrosomatic voltage transfer. Second, equivalent cylinder models were used to compare the spatial profiles of Z(c) and dendrosomatic voltage transfer. These simulations showed that Z(c) is less affected by dendritic location than voltage transfer is. Third, compartmental models based on morphological reconstructions of five different neuron types were used to calculate Z(c), input impedance (Z(N)), and voltage transfer throughout the dendritic tree. For all neurons, there was no significant variation of Z(c) with location within higher-order dendrites. Furthermore, Z(c) was relatively independent of synaptic location throughout the entire cell in three of the five neuron types (CA3 interneurons, CA3 pyramidal neurons, and dentate granule cells). This was quite unlike Z(N), which increased with distance from the soma and was responsible for a parallel decrease of voltage transfer. Fourth, simulations of fast excitatory PSPs (EPSPs) were consistent with the analysis of Z(c); peak EPSP amplitude varied