Rutten W L, van Wier H J, Put J H
Department of Biomedical Engineering, Faculty of Electrical Engineering, Twente University, Enschede, The Netherlands.
IEEE Trans Biomed Eng. 1991 Feb;38(2):192-8. doi: 10.1109/10.76386.
Artificial electrical stimulation of peripheral nerves needs the development of multielectrode devices which stimulate individual fibers or small groups in a selective and sensitive way. To this end, a multielectrode array in silicon technology has been developed, as well as experimental paradigms and model calculations for sensitivity and selectivity measures. The array consists of twelve platinum electrode sites (10 x 50 microns at 50 microns interdistance) on a 45 microns thick tip-shaped silicon substrate and a Si3N4 insulating glass cover layer. The tip is inserted in the peroneal nerve of the rat during acute experiments to stimulate alpha motor fibers of the extensor digitorum longus muscle. Sensitivity calculations and experiments show a cubic dependence of the number of stimulated motor units on current amplitude of the stimulatory pulse (recruitment curves), starting at single motor level. Selectivity was tested by a method based on the refractory properties of neurons. At the lowest stimulus levels (for one motor unit) selectivity is maximal when two electrodes are separated by 200-250 microns, which was estimated also on theoretical grounds. The study provides clues for future designs of two- and three-dimensional devices.
外周神经的人工电刺激需要开发能够以选择性和灵敏方式刺激单个纤维或小群体的多电极装置。为此，已经开发出一种基于硅技术的多电极阵列，以及用于灵敏度和选择性测量的实验范式和模型计算。该阵列由位于45微米厚的尖端形硅基片上的十二个铂电极位点（尺寸为10×50微米，电极间距为50微米）和一层Si3N4绝缘玻璃覆盖层组成。在急性实验期间，将该尖端插入大鼠的腓神经中，以刺激趾长伸肌的α运动纤维。灵敏度计算和实验表明，从单个运动水平开始，受刺激运动单位的数量与刺激脉冲的电流幅度呈三次方关系（募集曲线）。通过基于神经元不应期特性的方法测试了选择性。在最低刺激水平（针对一个运动单位）下，当两个电极相距200 - 250微米时，选择性最大，这一点也从理论上得到了估计。该研究为未来二维和三维装置的设计提供了线索。
