Department of Computational Intelligence and System Science, Tokyo Institute of Technology, Yokohama, Japan.
Biophys J. 2010 Feb 17;98(4):524-33. doi: 10.1016/j.bpj.2009.10.041.
Under physiological and artificial conditions, the dendrites of neurons can be exposed to electric fields. Recent experimental studies suggested that the membrane resistivity of the distal apical dendrites of cortical and hippocampal pyramidal neurons may be significantly lower than that of the proximal dendrites and the soma. To understand the behavior of dendrites in time-varying extracellular electric fields, we analytically solved cable equations for finite cylindrical cables with and without a leak conductance attached to one end by employing the Green's function method. The solution for a cable with a leak at one end for direct-current step electric fields shows a reversal in polarization at the leaky end, as has been previously shown by employing the separation of variables method and Fourier series expansion. The solution for a cable with a leak at one end for alternating-current electric fields reveals that the leaky end shows frequency preference in the response amplitude. Our results predict that a passive dendrite with low resistivity at the distal end would show frequency preference in response to sinusoidal extracellular local field potentials. The Green's function obtained in our study can be used to calculate response for any extracellular electric field.
在生理和人为条件下，神经元的树突可以暴露在电场中。最近的实验研究表明，皮质和海马锥体神经元的远侧顶树突的膜电阻可能明显低于近侧树突和胞体的膜电阻。为了了解在时变细胞外电场中树突的行为，我们通过格林函数法对带有和不带有一端泄漏电导的有限圆柱形电缆的电缆方程进行了分析求解。对于一端带有泄漏的电缆，对于直流阶跃电场的解显示在泄漏端发生极化反转，这与以前采用变量分离法和傅里叶级数展开所得到的结果一致。对于一端带有泄漏的电缆，对于交流电电场的解表明，泄漏端在响应幅度上表现出频率偏好。我们的结果预测，在远端具有低电阻的被动树突对正弦细胞外局部场电位的反应会表现出频率偏好。我们研究中获得的格林函数可用于计算任何细胞外电场的响应。
