Department of Biomedical Engineering, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America.
PLoS One. 2013;8(3):e59839. doi: 10.1371/journal.pone.0059839. Epub 2013 Mar 28.
Deep brain stimulation (DBS) is a common therapy for treating movement disorders, such as Parkinson's disease (PD), and provides a unique opportunity to study the neural activity of various subcortical structures in human patients. Local field potential (LFP) recordings are often performed with either intraoperative microelectrodes or DBS leads and reflect oscillatory activity within nuclei of the basal ganglia. These LFP recordings have numerous clinical implications and might someday be used to optimize DBS outcomes in closed-loop systems. However, the origin of the recorded LFP is poorly understood. Therefore, the goal of this study was to theoretically analyze LFP recordings within the context of clinical DBS applications. This goal was achieved with a detailed recording model of beta oscillations (∼20 Hz) in the subthalamic nucleus. The recording model consisted of finite element models of intraoperative microelectrodes and DBS macroelectrodes implanted in the brain along with multi-compartment cable models of STN projection neurons. Model analysis permitted systematic investigation into a number of variables that can affect the composition of the recorded LFP (e.g. electrode size, electrode impedance, recording configuration, and filtering effects of the brain, electrode-electrolyte interface, and recording electronics). The results of the study suggest that the spatial reach of the LFP can extend several millimeters. Model analysis also showed that variables such as electrode geometry and recording configuration can have a significant effect on LFP amplitude and spatial reach, while the effects of other variables, such as electrode impedance, are often negligible. The results of this study provide insight into the origin of the LFP and identify variables that need to be considered when analyzing LFP recordings in clinical DBS applications.
深部脑刺激 (DBS) 是治疗运动障碍的常用疗法，如帕金森病 (PD)，并为研究人类患者各种皮质下结构的神经活动提供了独特的机会。局部场电位 (LFP) 记录通常使用术中微电极或 DBS 导联进行，反映基底神经节核内的振荡活动。这些 LFP 记录具有许多临床意义，并且有朝一日可能用于在闭环系统中优化 DBS 结果。然而，记录的 LFP 的起源尚不清楚。因此，本研究的目的是从理论上分析临床 DBS 应用中 LFP 的记录。这一目标是通过在亚丘脑核中进行β振荡（约 20 Hz）的详细记录模型来实现的。记录模型由植入大脑的术中微电极和 DBS 宏观电极的有限元模型以及 STN 投射神经元的多腔电缆模型组成。模型分析允许系统地研究许多可能影响记录 LFP 组成的变量（例如电极尺寸、电极阻抗、记录配置以及大脑、电极-电解质界面和记录电子设备的滤波效果）。该研究的结果表明，LFP 的空间范围可以延伸几毫米。模型分析还表明，诸如电极几何形状和记录配置等变量对 LFP 幅度和空间范围有显著影响，而诸如电极阻抗等其他变量的影响通常可以忽略不计。这项研究的结果提供了对 LFP 起源的深入了解，并确定了在分析临床 DBS 应用中的 LFP 记录时需要考虑的变量。
