MICROMACHINED STIMULATING MICROELECTRODE ARRAYS

许多潜在的神经假体，包括视觉、听觉和运动假体，在微电极阵列被开发出来之前将是不可行的，这些微电极阵列允许独立地刺激多个小神经元簇。该项目将涉及薄膜微电极阵列的研究和开发，该阵列能够独立刺激多达512个这样的小细胞簇。具体地说，这些微电极阵列的设计是为了在视觉皮质、耳蜗核和腰椎脊髓的多个位置提供微刺激。硅的微加工与微机械结构上的电子电路集成相结合，允许在多个杆上制造具有多个刺激点的有源电路微电极。目前正在开发的微电极阵列将刺激点放置在8到16个穿透小腿上。这些现场的二维微电极阵列可以组装成具有512个刺激点的三维阵列。与传统的线束微电极相比，这种薄膜刺激微电极在多部位、高选择性刺激方面具有许多优点。它们的刺激部位密度至少比线束电极大一个数量级，并允许刺激部位间距与神经元的尺寸相当。这些设计提供了一种电路，允许体外为许多神经刺激点产生刺激指令，将其组合成单一信号，然后通过植入物上的集成电子设备进行解码。集成电子设备还允许将阵列设计为具有集成遥测功能，从而消除了对系缆的需要。

Many potential neural prostheses, including visual, auditory, and motor prostheses, will not be feasible until microelectrode arrays are developed that allow multiple, small clusters of neurons to be independently stimulated. This project will involve research and development on thin-film microelectrode arrays capable of independently stimulating as many as 512 such small clusters of cells. Specifically, these microelectrode arrays are being designed to provide microstimulation at multiple sites in the visual cortex, the cochlear nucleus and the lumbrosacral spinal cord. Micromachining of silicon, combined with integration of electronic circuits on the micromachined structure, permits fabrication of active circuit microelectrodes with multiple stimulating sites on multiple shanks. Microelectrode arrays currently under development have 64 stimulation sites placed along 8 or 16 penetrating shanks. These 64-site, two-dimensional microelectrode arrays can be assembled into a 3-dimensional array with 512 stimulating sites. These thin- film stimulating microelectrodes have several advantages over more conventional wire bundle microelectrodes for multiple site, highly selective stimulation. Their stimulating site density is at least an order of magnitude greater than wire bundle electrodes and permits stimulation site spacing with dimensions comparable to the dimensions of neurons. The designs provide circuitry which permits extracorporeally generated stimulus instructions for many neural stimulating sites to be combined into a single signal and then decoded by integrated electronics on the implant. The integrated electronics also permit the arrays to be designed with integrated telemetry, eliminating the need for tethering cables.