Rossel Olivier, Soulier Fabien, Bernard Serge, Guiraud David, Cathébras Guy
DEMAR Team, INRIA, Montpellier, France.
LIRMM (Laboratoire d'Informatique de Robotique et de Microélectronique de Montpellier), Université Montpellier, Montpellier, France.
Med Biol Eng Comput. 2016 Aug;54(8):1257-67. doi: 10.1007/s11517-016-1463-3. Epub 2016 Mar 25.
Electrode designs and strategies for electroneurogram recordings are often tested first by computer simulations and then by animal models, but they are rarely implanted for long-term evaluation in humans. The models show that the amplitude of the potential at the surface of an axon is higher in front of the nodes of Ranvier than at the internodes; however, this has not been investigated through in vivo measurements. An original experimental method is presented to emulate a single fiber action potential in an infinite conductive volume, allowing the potential of an axon to be recorded at both the nodes of Ranvier and the internodes, for a wide range of electrode-to-fiber radial distances. The paper particularly investigates the differences in the action potential amplitude along the longitudinal axis of an axon. At a short radial distance, the action potential amplitude measured in front of a node of Ranvier is two times larger than in the middle of two nodes. Moreover, farther from the phantom axon, the measured action potential amplitude is almost constant along the longitudinal axis. The results of this new method confirm the computer simulations, with a correlation of 97.6 %.
用于记录神经电图的电极设计和策略通常首先通过计算机模拟进行测试，然后通过动物模型进行测试，但很少植入人体进行长期评估。模型显示，轴突表面的电位幅度在郎飞结前方比在结间更高；然而，这尚未通过体内测量进行研究。本文提出了一种原始实验方法，用于在无限导电体积中模拟单纤维动作电位，从而能够在广泛的电极与纤维径向距离范围内，在郎飞结和结间记录轴突的电位。本文特别研究了沿轴突纵轴的动作电位幅度差异。在较短的径向距离下，在郎飞结前方测得的动作电位幅度比在两个结中间测得的大两倍。此外，离虚拟轴突越远，沿纵轴测得的动作电位幅度几乎恒定。这种新方法的结果证实了计算机模拟，相关性为97.6%。
