Long-Term Neural Recordings Using MEMS Based Movable Microelectrodes in the Brain.
Long-Term Neural Recordings Using MEMS Based Movable Microelectrodes in the Brain.
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DOI：
10.3389/fneng.2010.00010
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发表时间：
2010-01-01
期刊：
影响因子：
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通讯作者：
Muthuswamy, Jit
中科院分区：
文献类型：
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作者：
Jackson, Nathan;Sridharan, Arati;Muthuswamy, Jit
新兴的神经假体设备的关键要求之一是在长时间内保持良好质量的神经记录。我们在这里报告了一种新的MEMS（微机电系统）为基础的技术，可以移动微电极在神经信号恶化的情况下采样一组新的神经元。微型电热致动器用于以大约9 μ m的步长可控地移动植入后的微电极。在这项研究中，共12个可移动微电极芯片单独植入成年大鼠。12个可移动微电极芯片中的两个在3周内不移动，并作为对照实验。在植入的前3周期间，移动微电极导致平均信噪比（SNR）从移动前的14.61 +/-5.21 dB改善到所有微电极和所有日期移动后的18.13 +/-4.99 dB。然而，噪声幅度的平均均方根值在微电极移动之前和之后在2.98 +/-1.22 μ V和3.01 +/-1.16 μ V是相似的。超过3周，观察到的主要失效模式是PMMA（牙科粘固剂）基颅骨支架的生物排斥，导致器械松动并最终从颅骨上脱落。此外，在微电极移动前，3周后功能正常的器械的平均SNR为11.88 +/-2.02 dB，与移动后的平均SNR 13.34 +/-0.919 dB有显著差异（p <0.01）。这项研究的结果表明，基于MEMS的技术可以在长期实验中移动啮齿动物大脑中的微电极，从而改善信号质量。包装和手术技术的进一步改进将有可能使可移动微电极在慢性实验中记录皮层神经元活动。
One of the critical requirements of the emerging class of neural prosthetic devices is to maintain good quality neural recordings over long time periods. We report here a novel MEMS (Micro Electro Mechanical Systems) based technology that can move microelectrodes in the event of deterioration in neural signal to sample a new set of neurons. Microscale electro-thermal actuators are used to controllably move microelectrodes post-implantation in steps of approximately 9 mum. In this study, a total of 12 movable microelectrode chips were individually implanted in adult rats. Two of the twelve movable microelectrode chips were not moved over a period of 3 weeks and were treated as control experiments. During the first 3 weeks of implantation, moving the microelectrodes led to an improvement in the average signal to noise ratio (SNR) from 14.61 +/- 5.21 dB before movement to 18.13 +/- 4.99 dB after movement across all microelectrodes and all days. However, the average root-mean-square values of noise amplitudes were similar at 2.98 +/- 1.22 muV and 3.01 +/- 1.16 muV before and after microelectrode movement. Beyond 3 weeks, the primary observed failure mode was biological rejection of the PMMA (dental cement) based skull mount resulting in the device loosening and eventually falling from the skull. Additionally, the average SNR for functioning devices beyond 3 weeks was 11.88 +/- 2.02 dB before microelectrode movement and was significantly different (p < 0.01) from the average SNR of 13.34 +/- 0.919 dB after movement. The results of this study demonstrate that MEMS based technologies can move microelectrodes in rodent brains in long-term experiments resulting in improvements in signal quality. Further improvements in packaging and surgical techniques will potentially enable movable microelectrodes to record cortical neuronal activity in chronic experiments.