Fundamental Properties of Micromagnetics for Peripheral and Central Nervous System Stimulation

最近的神经工程研究表明，神经退行性疾病患者的运动功能和感觉可以通过神经电刺激部分恢复。然而，目前用于替代内源性电激活的电极阵列存在一些缺点，包括金属触点暴露于导电组织，当电极尺寸小时可能需要过高的电荷密度来实现刺激，以及电极触点与神经组织之间的不完全接触缺乏耐受性。pi最近证明了一种新型微线圈可以有效地刺激周围神经系统，这导致了可植入设备和神经假体的磁性微刺激器可以被设计出来的想法。由于磁刺激机制以涡流及其梯度为中心，线圈不需要与组织直接接触，因此它们可以完全绝缘，从而避免了与导电神经或周围组织发生物质反应的可能性。此外，线圈阵列可以潜在地提供更多的选择来控制感应磁场的形状，因此涡流，它们的操作不受接触电容的影响。智力价值：我们提出的工作目标是利用我们的理论和实验发现，即接触磁刺激神经系统是可行的，并研究特别适合微磁刺激的新型微线圈和磁刺激器。具体来说，一个主要目标是研究允许控制微线圈的线圈几何形状。S磁场；这将大大提高磁通密度水平，远远超过传统线圈的水平，并改变目标神经元附近的磁场方向。铁氧体支持的微线圈阵列有可能提供增加的磁场强度，尖锐的梯度，以及控制选择性神经刺激所需的磁场。在这项工作中，pi研究了与传统电神经刺激器相比可以提供范式转变的新型设备。更广泛的影响：这项工作有可能为外周和中枢系统神经刺激装置提供一种高度创新的解决方案。提供表面电极或穿透电极的替代方案可能会对许多植入式系统产生积极影响，这些系统目前受到电神经刺激的显著缺点的影响。除了重要的临床影响，拟议的计划提供了独特的机会，培养工程学生在工程技术和医学研究的前沿高度跨学科的活动。除了在各种现有项目中利用拟议的研究活动，旨在对当前和未来的本科生产生持久的影响外，拟议的项目还将增加工程专业学生对神经修复学新兴领域的兴趣，并展示工程对医学的好处。pi将通过外展计划为K-12, 2年和4年的支线学校和大学提供额外的学习机会。

Recent neuroengineering research has demonstrated that motor function and sensing in patients that are affected by neurodegenerative diseases can be partially restored by means of electrical neurostimulation. However, electrode arrays currently used to replace endogenous electrical activation present several drawbacks, including exposure of metal contacts to conductive tissue, potential need for excessive charge density to achieve stimulation when electrode size is small, and lack of tolerance with respect to imperfect contact between the electrode contacts and the neural tissue.The PIs have recently demonstrated that a new class of microcoils can effectively stimulate the peripheral nervous system, leading to the idea that magnetic microstimulators for implantable devices and neuroprostheses can be devised. Since the mechanisms of magnetic stimulation are centered on eddy currents and their gradients, coils do not need direct contact with the tissue and therefore they can be completely insulated, thus avoiding the possibility of material reactions with conductive neural or surrounding tissues. Further, arrays of coils can potentially offer more options to control the shape of the induced magnetic fields, and therefore eddy currents, and their operation is not affected by contact capacitance. Intellectual Merit: The goals of the proposed work capitalize on our theoretical and experimental findings that contact magnetic stimulation of the nervous system is feasible, and investigate new classes of microcoils and magnetic stimulators that will be particularly suited for micromagnetic stimulation. Specifically, a major goal is to investigate coil geometries that allow control of the microcoil?s magnetic fields; this will increase the magnetic flux density levels well beyond those of traditional coils and alter the orientation of the fields in the proximity of the target neurons. Ferrite-backed microcoil arrays have the potential to provide increased field strength, sharp gradients, and control of the magnetic field needed for selective neurostimulation. In this work, the PIs investigate novel devices that could provide a paradigm shift compared to traditional electrical neurostimulators. Broader Impacts: This work has the potential to offer a highly innovative solution to peripheral and central system neurostimulation devices. Providing an alternative solution to surface or penetrating electrodes could positively impact a number of implantable systems, which currently suffer from the significant drawbacks of electrical neural stimulation. Besides the important clinical impact, the proposed program offers unique opportunities to train engineering students in a highly interdisciplinary activity at the forefront of engineering technology and medical research. In addition to utilizing the proposed research activity in various existing programs designed to have a lasting impact on current and prospective undergraduate students, the proposed project will increase the interest of engineering students in the emerging field of neuroprosthetics and demonstrate the benefits of engineering to medicine. The PIs will provide additional learning opportunities targeted at K-12, 2-year, and 4-year feeder schools and colleges through outreach programs.