Optimization of micro-coil arrays for precise stimulation of visual cortex

项目摘要 已经提出通过植入微电极阵列对初级视觉皮层（V1）进行电刺激作为一种有效的方法。 是指为患有各种视力障碍的人恢复视力。尽管有一些初步的临床 尽管取得了成功，但由于此类设备无法选择性地针对特定目标，系统性进展受到了限制 神经元亚群以及异物反应和其他可能损害 植入物的长期功效。我们的目标是提高皮质激素的有效性和可靠性 通过开发用于皮层内磁刺激的微线圈阵列来植入。基于线圈的磁刺激 与基于电极的电刺激相比具有几个重要的优点。第一，电动 由线圈感应的场是空间不对称的 皮质中的锥体神经元，而不激活其他皮质区域的水平通过轴突， 从而增强皮层刺激的空间分辨率。第二，磁场产生于 线圈对任何生物组织具有高的渗透性 神经胶质瘢痕包封皮质植入物，从而继续可靠地诱导电场， 目标区域。第三，通过气密密封整个装置，可以使微线圈阵列更可靠 具有介电涂层，因此不会受到水渗透引起的器件退化的困扰 通过暴露的电极和电介质涂层之间的弱结合和/或 在慢性刺激过程中，薄金属电极从基板上脱落。因此，基于线圈的方法提供了 更有效、更可靠的皮质假体神经刺激方法。这样做的目的是 建议通过优化视觉假体的设计， 微线圈阵列，开发更有效的刺激策略，并在小鼠中建立疗效， 因视网膜变性而失明（rd 10）。

Project Summary Electrical stimulation of primary visual cortex (V1) via implanted microelectrode arrays has been proposed as a means to restore vision to those suffering from a wide range of visual impairments. Despite some initial clinical success, systematic advances have been limited by an inability of such devices to selectively target specific neuronal sub-populations as well as by the foreign body responses and other reactions that can compromise the long-term efficacy of implants. Our goal here is to enhance the efficacy and the reliability of cortical implants by developing a micro-coil array for intracortical magnetic stimulation. Coil-based magnetic stimulation has several important advantages when compared to electrode-based electric stimulation. First, the electric fields induced by the coils are spatially asymmetric and can therefore be used to selectively activate vertical pyramidal neurons in the cortex without also activating the horizontal passing axons of other cortical areas, thereby enhancing the spatial resolution of cortical stimulation. Second, the magnetic fields arising from the coils have high permeability to any biological tissue and so they can pass readily through the high impedance glial scarring that encapsulates cortical implants and thus continue to reliably induce electric fields in the targeted area. Third, the micro-coil array can be made more reliable by hermetically sealing the entire device with dielectric coatings so that it will not be plagued by the device degradation caused by water infiltration through the weak bonding between the exposed electrode and the dielectric coating and/or delamination of the thin metal electrode from the substrate during chronic stimulation. Thus, the coil-based approach provides a more effective and more reliable approach for neural stimulation with cortical prostheses. The aims of this proposal are to further enhance the efficacy and reliability of visual prosthetics by optimizing the design of a micro-coil array, developing more effective stimulation strategies, and establishing efficacy in mice that are blind due to retinal degeneration (rd10).