Multiplexed neural recording along a single optical fiber via optical reflectometry.
Multiplexed neural recording along a single optical fiber via optical reflectometry.
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DOI：
10.1117/1.jbo.21.5.057003
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发表时间：
2016-05-01
影响因子：
3.5
通讯作者：
Boyden ES
中科院分区：
文献类型：
--
作者：
Rodriques SG;Marblestone AH;Scholvin J;Dapello J;Sarkar D;Mankin M;Gao R;Wood L;Boyden ES
我们介绍了一种用于无造影剂的神经记录的光纤结构的设计和理论分析，该结构将神经电信号转换成多路光学读出。我们的传感器设计灵感来自电光调制器，它通过在电光核心材料上施加电压来调制波导的折射率。我们估计，这种设计将允许记录位于沿10厘米长的光纤的点上的单个神经元的活动，轴向分辨率和灵敏度低到使用商业上可用的光学反射计作为读出设备。神经记录部位检测与参考的电势差，并将该电势施加到电容器上。波导作为电容器的一个极板，因此电容器上的电荷积累会产生光学效应。该设计的一个关键概念是，可以通过增加电容来提高灵敏度。为了使电容最大化，我们利用了一层具有高相对介电常数的微观材料。如果能找到合适的材料--单位面积具有高电容，并且在毒性、光衰减、欧姆结和表面电容方面具有良好的性能--那么原则上可以将这种传感纤维缩小到几个微米的横截面，用于微创神经接口。我们研究了这些材料需求，并提出了潜在的材料选择。因此，使用反射读数探测的定制设计的多材料光纤可能会为神经传感提供一个强大的平台。
We introduce the design and theoretical analysis of a fiber-optic architecture for neural recording without contrast agents, which transduces neural electrical signals into a multiplexed optical readout. Our sensor design is inspired by electro-optic modulators, which modulate the refractive index of a waveguide by applying a voltage across an electro-optic core material. We estimate that this design would allow recording of the activities of individual neurons located at points along a 10-cm length of optical fiber with axial resolution and sensitivity down to using commercially available optical reflectometers as readout devices. Neural recording sites detect a potential difference against a reference and apply this potential to a capacitor. The waveguide serves as one of the plates of the capacitor, so charge accumulation across the capacitor results in an optical effect. A key concept of the design is that the sensitivity can be improved by increasing the capacitance. To maximize the capacitance, we utilize a microscopic layer of material with high relative permittivity. If suitable materials can be found—possessing high capacitance per unit area as well as favorable properties with respect to toxicity, optical attenuation, ohmic junctions, and surface capacitance—then such sensing fibers could, in principle, be scaled down to few-micron cross-sections for minimally invasive neural interfacing. We study these material requirements and propose potential material choices. Custom-designed multimaterial optical fibers, probed using a reflectometric readout, may, therefore, provide a powerful platform for neural sensing.