Smart MEMS recording systems for visual cortical studies

描述（申请人提供）：本提案的目的是设计和构建一种智能MEMS设备，用于记录视觉神经系统中的多细胞活动。这种小型化和可植入的微电极阵列系统将自动调整电极的深度，以优化记录性能。该系统的基本原理是改善视觉系统中神经元群体的长期慢性记录，用于科学和神经假体应用。具有固定电极几何形状的当前系统不能被调整以在产量或细胞类型方面优化记录。此外，这些系统不能随时间“跟随”细胞以克服由于组织相对于电极的移动而导致的信号损失。手动系统的缺点是在科学研究中对于大阵列变得难以管理，并且对于用于修复应用的永久性植入物是不可接受的。所提出的系统通过基于记录的信号质量自动化每个电极的位置来克服所有这些缺点。 这项研究的第一个目的是开发算法来自动搜索和保存来自神经元的记录信号。初步数据表明，这是可能的皮层神经元记录清醒，行为猴子和麻醉大鼠。第二个目标是开发具有低散热性的MEMS致动器，其可以用最小的能量应用锁定，并且可以提供大的位移。初步研究表明，由合作研究者之一开发的电解执行器是这种应用的理想选择。目标三将把早期目标中开发的所有组件整合到一个单一的系统中。该设备将包括一个基于MEMS的多电极阵列，具有独立可移动的电极，以及板载控制，监测和通信电路。虽然这是一个开发技术的提议，但一个基本假设是，该系统将大大改善多单元慢性记录，而不是固定几何系统所能实现的。这一假设将首先通过麻醉大鼠的皮层记录进行测试，然后通过行为猴子的视觉皮层区域记录进行测试。

DESCRIPTION (PROVIDED BY APPLICANT): The purpose of this proposal is to design and build a smart MEMs device for recording multicellular activity in the visual nervous system. This miniaturized and implantable microelectrode array system will automatically adjust the depths of the electrodes to optimize recording performance. The rationale for this system is to improve long term, chronic recording from populations of neurons in the visual system for scientific and neuroprosthetic applications. Current systems with fixed electrode geometries cannot be adjusted to optimize recordings in terms of yield or cell type. Moreover, these systems cannot "follow" cells over time to overcome loss of signal due to movement of the tissue with respect to the electrodes. Manual systems have the drawback of becoming unmanageable for large arrays in scientific studies, and unacceptable for permanent implants for prosthetics applications. The proposed system overcomes all of these drawbacks by automating the position of each electrode based on recorded signal quality. The first aim of this study is to develop algorithms to automatically search for, and hold, recorded signals from neurons. Preliminary data show that this is possible for cortical neurons recorded from awake, behaving monkeys and anesthetized rats. The second aim is to develop MEMS actuators that have low heat dissipation, are lockable with minimal energy application, and can provide large displacements. Preliminary studies indicate that electrolysis actuators developed by one of the co-investigators are ideal for this application. Aim three will integrate all of the components developed in the earlier aims into a single system. This device will consist of a MEMS-based multielectrode array with independently moveable electrodes, and on-board control, monitoring and communications circuits. Although this is a proposal to develop technology, an underlying hypothesis is that this system will improve multiunit, chronic recordings substantially over what can be achieved with fixed geometry systems. This hypothesis will be tested initially with cortical recordings in anesthetized rats followed by recordings from visual cortical areas in behaving monkeys.