Walter J S, Griffith P, Sweeney J, Scarpine V, Bidnar M, McLane J, Robinson C
Rehabilitation Research and Development Center, Edward Hines Jr. Hospital, Department of Veterans Affairs, Hines, IL, USA.
J Spinal Cord Med. 1997 Apr;20(2):233-43. doi: 10.1080/10790268.1997.11719475.
In this study, an electrode system consisting of twelve small platinum dot electrodes imbedded in a spiral silicone rubber insulating cuff was used to investigate the feasibility of selective (regional) stimulation of the median nerves of the raccoon. Acute experiments in four raccoons consisted of functional responses observations, isometric force recordings from tendon attachments and postmortem fascicular mapping. Functional responses (elbow, wrist and/or digit flexion, pronation and/or thumb abduction) to selective stimulation were noted as dependent upon cuff electrode configuration (longitudinal tripole with and without field steering, as well as a transverse bipolar arrangement) and current level (threshold, 1/2 maximal, maximal). Muscle force recruitment curves (force as a function of stimulus amplitude) were plotted for flexor digitorum superficialis, flexor digitorum profundus, flexor carpi radialis, palmaris longus and pronator teres of three raccoons. Fascicular maps at the level of the nerve cuff were created indicating the approximate position of innervation to each of the aforementioned muscles, as well as other innervation such as paw fascicles, sensory fascicles, and elbow innervation (such as coracobrachialis). The greatest selectivity was observed at or near threshold current levels. In all four raccoons studied, a threshold electrode choice and stimulation strategy could be identified enabling selective production of either digit flexion, wrist flexion and/or digit and wrist flexion. It was possible to elicit a selective pronation response at threshold in three of the four animals. Selective elbow flexion at threshold could be produced in all four experiments. With stronger currents, additional movements were usually induced. The raccoon therefore appears to be a suitable, if challenging, animal model for further development of not only nerve cuff electrode approaches but perhaps other stimulation electrode technologies prior to human neuroprosthetic studies.
在本研究中，使用了一种电极系统，该系统由嵌入螺旋硅橡胶绝缘袖带中的十二个小铂点电极组成，用于研究选择性（局部）刺激浣熊正中神经的可行性。对四只浣熊进行的急性实验包括功能反应观察、肌腱附着处的等长力记录以及死后束状图谱绘制。记录了对选择性刺激的功能反应（肘部、腕部和/或手指屈曲、旋前和/或拇指外展），发现其取决于袖带电极配置（带和不带场控制的纵向三极以及横向双极排列）和电流水平（阈值、最大电流的1/2、最大电流）。绘制了三只浣熊的指浅屈肌、指深屈肌、桡侧腕屈肌、掌长肌和旋前圆肌的肌肉力量募集曲线（力量作为刺激幅度的函数）。创建了神经袖带水平的束状图谱，显示了上述各肌肉的大致神经支配位置，以及其他神经支配，如爪束、感觉束和肘部神经支配（如肱二头肌）。在阈值电流水平或接近阈值电流水平时观察到最大的选择性。在所有四只研究的浣熊中，可以确定一种阈值电极选择和刺激策略，从而能够选择性地产生手指屈曲、腕部屈曲和/或手指与腕部屈曲。在四只动物中的三只中，可以在阈值水平引发选择性旋前反应。在所有四个实验中，都可以在阈值水平产生选择性肘部屈曲。随着电流增强，通常会诱发额外的运动。因此，浣熊似乎是一种合适的动物模型，尽管具有挑战性，不仅可用于进一步开发神经袖带电极方法，或许还可用于在人体神经假体研究之前开发其他刺激电极技术。
