Abboud S, Rosenfeld M, Luzon J
Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Israel.
IEEE Trans Biomed Eng. 1996 Jul;43(7):690-6. doi: 10.1109/10.503176.
The correlation between source asymmetry in the brain and the potential amplitude asymmetry on the scalp was studied by a two-dimensional (2-D) numerical model of the head. The model employed computerized tomography (CT) images to define the different compartments of the head. The source was modeled by a dipole layer in the occiput for an occipital source (visual evoked potential generators) or a dipole layer around the cortex representing spontaneous activity generators. The volume conductor equation for the potential distribution was solved numerically using a finite volume method for two CT images; one had relatively symmetric left-right anatomy while the other had a falx deviation of 6 degrees between the occiput and the nasion-inion line. By examining several arrangements of sources, it has been demonstrated that source asymmetry can cause nonnegligible asymmetry in the potential amplitude at the homotopic points on the scalp. This asymmetry, that is not related to real physiologic or psychological origin, should be taken into consideration in any EEG potential distribution analysis.
通过头部的二维（2-D）数值模型研究了大脑中源不对称与头皮上电位幅度不对称之间的相关性。该模型采用计算机断层扫描（CT）图像来定义头部的不同区域。对于枕部源（视觉诱发电位发生器），源由枕部的偶极层建模；对于代表自发活动发生器的源，源由皮质周围的偶极层建模。使用有限体积法对两个CT图像数值求解电位分布的体积导体方程；一个具有相对对称的左右解剖结构，而另一个在枕部与鼻根-枕骨线之间有6度的大脑镰偏移。通过检查源的几种排列方式，已证明源不对称可导致头皮上同位点处电位幅度出现不可忽略的不对称。这种与真实生理或心理起源无关的不对称，在任何脑电图电位分布分析中都应予以考虑。
