A MIMO channel approach for characterizing electrode-tissue interface in long-term chronic microelectrode array recordings.
A MIMO channel approach for characterizing electrode-tissue interface in long-term chronic microelectrode array recordings.
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一种 MIMO 通道方法，用于表征长期慢性微电极阵列记录中的电极组织界面。
DOI：
10.1109/iembs.2006.260055
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Oweiss,KarimG
中科院分区：
文献类型：
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作者：
Oweiss,KarimG
表征在慢性植入物中由微电极阵列周围的胶质瘢痕形成引起的封装层一直是广泛研究的主题。通常，等效电路模型用于通过非线性拟合电阻抗谱（EIS）数据来表征反应性组织响应。该模型假设包封组织的时不变相邻层在每个电极部位上具有相同的结构。在本文中，提出了一种替代方法的基础上建模的封装层作为一个随时间变化的通信信道。该信道的特征在于具有时变系数的多输入多输出（MIMO）传递函数。该模型避免了现有EIS等效电路模型的空间分辨率限制。它还允许捕获所观察到的神经信号质量随时间的变化。我们表明，“均衡”的信道使用此模型可以产生信号质量的大幅改善。随着高密度电极阵列用于皮层植入的趋势，所提出的模型更适合于均衡衰落信道，并以更高的精度解释记录的信号。我们还展示了如何模式化的波形可以定期被用来探测信道，如果可以避免不利影响的概念。这可以潜在地改善信道估计器性能，特别是当小区迁移发生时
Characterizing the encapsulation layer caused by glial scar formation surrounding microelectrode arrays in chronic implants has been the subject of extensive research. Typically, an equivalent circuit model is used to characterize the reactive tissue response by nonlinearly fitting the electrical impedance spectroscopy (EIS) data. This model assumes a time invariant adjacent layer of encapsulation tissue to have the same structure on every electrode site. In this paper, an alternative approach is proposed based on modeling the encapsulation layer as a time varying communication channel. The channel is characterized by a multi-input multi-output (MIMO) transfer function with time varying coefficients. This model circumvents spatial resolution limitations of existing EIS equivalent circuit models. It further allows capturing the observed changes in neural signal quality over time. We show that "equalizing" the channel using this model can yield a substantial improvement in signal quality. With tendency towards high-density electrode arrays for cortical implantation, the proposed model is better suited to equalize the fading channel and interpret the recorded signals with higher accuracy. We also show conceptually how patterned waveforms can periodically be used to probe the channel if adverse effects can be avoided. This can potentially improve the channel estimator performance, particularly when cell migration occurs