On the calculation of magnetic fields based on multipole modeling of focal biological current sources.
On the calculation of magnetic fields based on multipole modeling of focal biological current sources.
复制标题
基于焦点生物电流源多极建模的磁场计算。
DOI：
10.1016/s0006-3495(97)78158-x
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发表时间：
1997
影响因子：
3.4
通讯作者：
G. Curio
中科院分区：
文献类型：
--
作者：
G. Nolte;G. Curio
空间受限的生物电流分布，如电刺激人体躯体感觉皮质的初级神经元反应，可以用电流多极展开来充分描述。本文根据偶极子磁场的n阶导数，导出了电流多极感应磁场的解析计算公式。对于任意阶，所需的微分算符以封闭形式给出。该概念以不同的形式实现，用于标量以及并矢格林函数的展开，后者允许分离那些电静默但可磁检测的多极源分量。所得公式一般适用于任意形状的体导体中的电流源。利用神经生理学相关的源参数，给出了具有解析给定偶极子场的球形体积导体的例子。对直到八极项的多极系数的信噪比分析表明，皮层电流源的横向范围可以通过脑磁图记录来检测。
Spatially restricted biological current distributions, like the primary neuronal response in the human somatosensory cortex evoked by electric nerve stimulation, can be described adequately by a current multipole expansion. Here analytic formulas are derived for computing magnetic fields induced by current multipoles in terms of an nth-order derivative of the dipole field. The required differential operators are given in closed form for arbitrary order. The concept is realized in different forms for an expansion of the scalar as well as the dyadic Green's function, the latter allowing for separation of those multipolar source components that are electrically silent but magnetically detectable. The resulting formulas are generally applicable for current sources embedded in arbitrarily shaped volume conductors. By using neurophysiologically relevant source parameters, examples are provided for a spherical volume conductor with an analytically given dipole field. An analysis of the signal-to-noise ratio for multipole coefficients up to the octapolar term indicates that the lateral extent of cortical current sources can be detected by magnetoencephalographic recordings.