64通道微電極量測系統之研製

Abstract

本研究的目的是要建立一個神經細胞群體訊號的量測平台，從多通道平面微電極的研製到放大濾波電路的設計與製作及整體系統的測試及驗證。 在本研究中利用了半導體製程技術製作一個64通道的平面微電極，其量測電極至外部電極連接點的阻值約為10 ± 4.65 Ω，並已完成電極外部之打線及封膠，方便將電極所量測到的神經電訊號藉此連接板傳送到後端系統中進行運算及分析。 其次是自行設計製作了16通道的放大濾波電路模組，使之可同時量測場電位及多細胞神經動作電位，此放大濾波電路整體放大倍率為2500倍，濾波器的設計是利用二階Butterworth低通濾波器及二階Bessel的帶通濾波器，其濾波頻帶分別為0.1 - 100 Hz及300 Hz - 3 kHz。每一模組16通道的設計增加了量測系統運用的彈性及未來的擴張性，並搭配市售之類比數位轉換介面達成整體神經細胞群體訊號的量測平台。

This study is to set up a measurement platform for the recording of neural ensemble. A 64-channel microelectrode, amplifiers, and filters were therefore designed and implemented. By utilizing the semiconductor processes, a 64-channel microelectrode was implemented in this thesis. The impedance of each electrode, measured with respect to the connecting pad, is only 10 ± 4.56 Ω. The bonding and package of this 64-chanel microelectrode was successfully tested, and enabling the transmission of the detected neuronal activities to the host system for signal processing. Further, a module each with a 16-channel amplifiers and 32-channel filters was designed and fully tested. This module can be used to measure field potential and multi-unit action potential at the same time. The gain of the amplifiers is programmed at 2500, whereas the passbands of the filters are 0.1 - 100 Hz for the Butterworth lowpass filters and 300 Hz – 3 kHz for the Bessel filters. The 2nd-order Butterworth lowpass filter is designed for field potential recording, while the 2nd-order Bessel bandpass filter was for extra-cellular multi-unit recording. A further advantage of the module design for the signal conditioning unit is the flexibility and expandability. This measurement system, in accompany with the A/D convector card, has successfully set up an indispensable platform for the recording of multichannel field potentials as well as action potentials.