Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America. Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America.
J Neural Eng. 2018 Jun;15(3):036027. doi: 10.1088/1741-2552/aab55f. Epub 2018 Mar 9.
The dorsal root ganglia (DRG) are promising nerve structures for sensory neural interfaces because they provide centralized access to primary afferent cell bodies and spinal reflex circuitry. In order to harness this potential, new electrode technologies are needed which take advantage of the unique properties of DRG, specifically the high density of neural cell bodies at the dorsal surface. Here we report initial in vivo results from the development of a flexible non-penetrating polyimide electrode array interfacing with the surface of ganglia.
Multiple layouts of a 64-channel iridium electrode (420 µm) array were tested, with pitch as small as 25 µm. The buccal ganglia of invertebrate sea slug Aplysia californica were used to develop handling and recording techniques with ganglionic surface electrode arrays (GSEAs). We also demonstrated the GSEA's capability to record single- and multi-unit activity from feline lumbosacral DRG related to a variety of sensory inputs, including cutaneous brushing, joint flexion, and bladder pressure.
We recorded action potentials from a variety of Aplysia neurons activated by nerve stimulation, and units were observed firing simultaneously on closely spaced electrode sites. We also recorded single- and multi-unit activity associated with sensory inputs from feline DRG. We utilized spatial oversampling of action potentials on closely-spaced electrode sites to estimate the location of neural sources at between 25 µm and 107 µm below the DRG surface. We also used the high spatial sampling to demonstrate a possible spatial sensory map of one feline's DRG. We obtained activation of sensory fibers with low-amplitude stimulation through individual or groups of GSEA electrode sites.
Overall, the GSEA has been shown to provide a variety of information types from ganglia neurons and to have significant potential as a tool for neural mapping and interfacing.
背根神经节（DRG）是有前途的感觉神经接口神经结构，因为它们提供了对初级传入细胞体和脊髓反射回路的集中访问。为了利用这种潜力，需要新的电极技术，利用 DRG 的独特特性，特别是背表面高浓度的神经细胞体。在这里，我们报告了一种与神经节表面接口的柔性非穿透性聚酰亚胺电极阵列的初步体内结果。
测试了多个 64 通道铱电极（420 µm）阵列的布局，其间距小至 25 µm。利用无脊椎动物海蛞蝓 Aplysia californica 的颊神经节开发了与神经节表面电极阵列（GSEA）的处理和记录技术。我们还证明了 GSEA 能够记录与各种感觉输入（包括皮肤刷、关节弯曲和膀胱压力）相关的猫腰骶部 DRG 的单元和多单位活动。
我们记录了通过神经刺激激活的各种 Aplysia 神经元的动作电位，并且在紧密间隔的电极位点上观察到单元同时发射。我们还记录了与来自猫 DRG 的感觉输入相关的单元和多单位活动。我们利用紧密间隔的电极位点上动作电位的空间过采样来估计神经源的位置，在 DRG 表面下方 25 µm 到 107 µm 之间。我们还使用高空间采样来证明一只猫的 DRG 可能存在空间感觉图谱。我们通过单个或多个 GSEA 电极位点的低幅度刺激来激活感觉纤维。
总的来说，GSEA 已被证明可以从神经节神经元提供多种信息类型，并且具有作为神经映射和接口工具的巨大潜力。
