Improvement of spatial selectivity and decrease of mutual information of tri-polar concentric ring electrodes
Improvement of spatial selectivity and decrease of mutual information of tri-polar concentric ring electrodes
复制标题
DOI：
10.1016/j.jneumeth.2007.06.007
复制
发表时间：
2007-09-30
影响因子：
3
通讯作者：
Besio, Walter G.
中科院分区：
文献类型：
--
作者：
Koka, Kanthaiah;Besio, Walter G.
脑电(EEG)信号本质上是时空的。脑电具有很好的时间分辨率，但通常不具有高空间分辨率。表面拉普拉斯增强了表面电活动记录的空间分辨率和选择性。与传统电极相比，同心圆环电极具有更好的空间分辨率，可以直接估计表面拉普拉斯效应。为此，我们对运动相关电位(MRP)信号进行了分析。使用原始配置中的三极环电极以及分别通过排除或短路三极版本的记录面而实现的双极和单极配置来记录信号。电极以35个阵列方案放置，围绕以C3为中心的Fz-Cz-Pz-P3-T5-T3-F7-F3之间的区域。数据分五步顺序测量，每次仅使用七个电极，在每一步之后移位，并在稍后的评估中对齐。受试者被提示按下微动开关。比较了不同电极系统记录的MRP信号的信噪比(SNR)、空间选择性和互信息(MI)，其中采用三极同心圆环电极系统记录的MRP信号的信噪比明显高于双极同心圆环电极和传统圆盘电极模拟系统。与所测试的其他两种电极配置相比，三极电极还显示出显著更高的空间选择性以及显著更少的位置间互信息。这些特性应该会使三极同心电极对脑电应用有利。(C)2007 Elsevier B.V.保留所有权利。
Electroencephalography (EEG) signals are spatio-temporal in nature. EEG has very good temporal resolution but typically does not possess high spatial resolution. The surface Laplacian enhances the spatial resolution and selectivity of the surface electrical activity recording. Concentric ring electrodes have been shown to estimate the surface Laplacian directly with significantly better spatial resolution than conventional electrodes.For this report movement-related potentials (MRP) signals were analyzed. The signals were recorded using tri-polar ring electrodes in the original configuration as well as in bipolar and unipolar configurations achieved by excluding or shorting recording surfaces of the tri-polar version, respectively. The electrodes were placed in an array scheme of 35, encompassing the area between Fz-Cz-Pz-P3-T5-T3-F7-F3 centered on C3. Data were measured in five steps sequentially using only seven electrodes at a time, displaced after each step and aligned during evaluation later. Subjects were cued to press a micro-switch. The signal-to-noise ratio (SNR), spatial selectivity, and mutual information (MI) of the MRP signals recorded with the different electrode systems were compared.The MRP signals recorded with the tri-polar concentric ring electrode system have significantly higher SNR than from bipolar concentric ring electrode and conventional disc electrode emulations. The tri-polar electrodes have also shown significantly higher spatial selectivity as well as significantly less mutual information between locations than the other two electrode configurations tested. These characteristics should make tri-polar concentric electrodes beneficial for EEG applications. (c) 2007 Elsevier B.V. All rights reserved.