A modified cable formalism for modeling neuronal membranes at high frequencies
A modified cable formalism for modeling neuronal membranes at high frequencies
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DOI：
10.1529/biophysj.107.113571
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发表时间：
2008-02-15
影响因子：
3.4
通讯作者：
Destexhe, Alain
中科院分区：
文献类型：
--
作者：
Bedard, Claude;Destexhe, Alain
体内皮层神经元的细胞内记录显示强烈的阈下膜电位（V-m）活动。V-m的功率谱密度在高频（> - 50hz）下呈现幂律结构，斜率近似于2.5。这种类型的频率缩放无法用传统模型来解释，因为无论是单室模型还是基于重构细胞形态的模型，其频率缩放斜率都接近于-4。这个斜率是由于薄膜电阻在高频时被电容短路，这种情况可能不现实。这里，我们将非理想电容整合到电缆方程中，以反映电容不能立即充电的事实。我们证明了所得到的非理想电缆模型可以用傅里叶变换解析求解。采用球棒模型的数值模拟得到了与实验中相似的频率标度膜电位活性。我们还讨论了使用非理想电容器对其他细胞特性的影响，如高频传输，在非理想电缆中增强，或树突中的电压衰减。这些结果表明，基于非理想电容器的电缆方程应该用于捕捉高频下神经元膜的行为。
Intracellular recordings of cortical neurons in vivo display intense subthreshold membrane potential (V-m) activity. The power spectral density of the V-m displays a power-law structure at high frequencies (>50 Hz) with a slope of similar to-2.5. This type of frequency scaling cannot be accounted for by traditional models, as either single-compartment models or models based on reconstructed cell morphologies display a frequency scaling with a slope close to -4. This slope is due to the fact that the membrane resistance is short-circuited by the capacitance for high frequencies, a situation which may not be realistic. Here, we integrate nonideal capacitors in cable equations to reflect the fact that the capacitance cannot be charged instantaneously. We show that the resulting nonideal cable model can be solved analytically using Fourier transforms. Numerical simulations using a ball-and-stick model yield membrane potential activity with similar frequency scaling as in the experiments. We also discuss the consequences of using nonideal capacitors on other cellular properties such as the transmission of high frequencies, which is boosted in nonideal cables, or voltage attenuation in dendrites. These results suggest that cable equations based on nonideal capacitors should be used to capture the behavior of neuronal membranes at high frequencies.