Sidman R D, Semel J S, Lagerlund T D, Ford M R
Department of Mathematics, University of Southwestern Louisiana Lafayette, USA.
J Neurosci Methods. 1996 Oct;68(2):175-84. doi: 10.1016/0165-0270(96)00060-x.
Although scalp potential distributions do not uniquely determine the location and configuration of neural generators, they are important because they provide the necessary conditions that any hypothesized sources must satisfy and suggest a basis for testing alternate source hypotheses. One problem that could confound the correct interpretation of scalp potentials is the choice of reference electrode. Changing the reference may make activity patterns and waveform components appear and disappear (Pascual-Marqui et al. (1988) Int. J. Neurosci., 43: 237-249). The cortical imaging technique (CIT), a method for approximating potential fields on the cortical surface, was used to test the effects of the choice of reference electrode on these fields. Simulated and empirical evoked potential scalp-recorded referential data were mathematically analyzed for the case in which the reference (linked-ears) was arbitrarily assumed to be at zero potential, and the case in which the reference was the 'average' electrode, the arithmetic mean of all of the scalp-recorded voltages in the referential montage. The results for the two references were similar. This is encouraging because potential measurements relative to a point at infinity (zero potential) are never available and the assumption that any actual reference used for a recording is at zero potential is therefore suspect.
尽管头皮电位分布不能唯一确定神经发生器的位置和形态，但它们很重要，因为它们提供了任何假设源必须满足的必要条件，并为检验替代源假设提供了基础。可能混淆头皮电位正确解释的一个问题是参考电极的选择。改变参考电极可能会使活动模式和波形成分出现或消失（帕斯夸尔-马奎等人，《国际神经科学杂志》，1988年，第43卷：237 - 249页）。皮层成像技术（CIT）是一种近似皮层表面电位场的方法，用于测试参考电极选择对这些场的影响。对于参考电极（双耳相连）被任意假定为零电位的情况，以及参考电极是“平均”电极（参考导联中所有头皮记录电压的算术平均值）的情况，对模拟和经验性诱发电位头皮记录的参考数据进行了数学分析。两种参考电极的结果相似。这令人鼓舞，因为相对于无穷远处一点（零电位）的电位测量永远无法实现，因此记录中使用的任何实际参考电极处于零电位的假设值得怀疑。
