An automated system for measuring tip impedance and among-electrode shunting in high-electrode count microelectrode arrays
An automated system for measuring tip impedance and among-electrode shunting in high-electrode count microelectrode arrays
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DOI：
10.1016/j.jneumeth.2008.12.020
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发表时间：
2009-04-15
影响因子：
3
通讯作者：
Clark, Gregory A.
中科院分区：
文献类型：
--
作者：
Gunalan, Kabilar;Warren, David J.;Clark, Gregory A.
用于神经元记录和刺激的稳健的高电极计数微电极阵列的开发和有效使用取决于对电极阻抗的有效监测以及这些阻抗如何随时间变化。在多电极阵列中，常规电极阻抗测量可能被电极之间可能的信号分流所混淆。此外，大多数现有的监测高电极数阵列中的阻抗的方法是劳动密集型的，需要一次手动测试一个单独的电极。我们开发了一种能够自动测量100个微电极阵列上每个微电极阻抗的系统，其具有1 kHz，10 mV正弦波。通过切换逻辑，测量阵列中每个电极的两个阻抗值：（1）未分流阻抗（可能代表实际头端阻抗）;（2）分流阻抗。这两个测量值用于计算从测试电极到阵列中所有其他电极的泄漏/分流路径的净阻抗。该系统测量的阻抗范围为300 Ω-10 M Ω。该系统通过简单的电阻梯形网络进行了验证，建模电极头端阻抗的测量值在独立测量值的2%范围内。此外，该系统可靠地显示了净分流阻抗的相对值，尽管高值被系统性地低估了。该自动化设备能够在5分钟内测量100微电极阵列的电极头端和净分流阻抗值。这些快速和可重复的测量允许随着时间的推移对高电极计数阵列进行定量评估。(C)2008 Elsevier B. V.保留所有权利。
The development and effective use of robust high-electrode-count microelectrode arrays for neuronal recording and stimulation depends on effective monitoring of electrode impedances and how these change over time. In multielectrode arrays, conventional electrode impedance measurements may be confounded by possible shunting of signals among electrodes. Additionally, most present methods to monitor impedances in high-electrode-count arrays are labor intensive, requiring manual testing of one individual electrode at a time. We have developed a system capable of automatically measuring the impedances of each microelectrode on a 100-microelectrode array with a 1-kHz, 10-mV sine wave. Through switching logic, two impedance values are measured for each electrode in an array: (1) the unshunted impedance (presumably representing the actual tip impedance); and (2) the shunted impedance. These two measurements are used to calculate the net impedance of leakage/shunting pathways from the test electrode through all the other electrodes in the array. The system measures impedances in the range of 300 Omega-10M Omega. The system was validated with simple resistor ladder networks, and measurements of the modeled electrode tip impedances were within 2% of independently measured values. Additionally, the system reliably indicated the relative values of the net shunting impedances, although high values were systematically underestimated. The automated device was capable of measuring electrode tip and net shunting impedance values for a 100-microelectrode array in 5 min. These rapid and repeatable measurements allow for the quantitative assessment of high-electrode-count arrays over time. (C) 2008 Elsevier B.V. All rights reserved.