Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America.
Department of Electrical and Computer Engineering, John Hopkins University, Baltimore, MD, United States of America.
J Neural Eng. 2023 Apr 28;20(2). doi: 10.1088/1741-2552/acc6f1.
. Electrical neuromodulation remains an effective therapy for multiple neurological disorders. One strategy to electrically stimulate nerves utilizes the interference of multiple high frequency waveforms. This technique, known as temporal interference stimulation or interferential current stimulation, has recently gained significant attention as a method to improve the state-of-the-art in neurostimulation in both animal studies and human clinical trials.Here we report our investigation into the fundamental properties of the neuronal response to these types of waveforms-the effects of carrier and envelope frequencies, thresholds, firing behavior, and phase and asymmetric interference patterns.We utilized a cuff electrode on the rat sciatic nerve to apply a variety of interferential signals. We recorded muscle activity in the plantar muscles and biceps femoris, which are proxies for activity on two of the major branches of the sciatic, which are spatially distinct in the target volume. We tested both fundamental recruitment properties as well as spatial techniques to selectively activate either muscle group.Our data suggest, contrary to the currently accepted explanation, that neurons do not extract envelopes at all, and that the response to these signals is well explained by a resistor-capacitor (i.e. integrator) membrane with a fixed firing threshold. Basic interference techniques do not change recruitment far from electrodes. Techniques can produce regions of both phasic activation and tonic activation/conduction block.An integrator model suggests that interference techniques are less capable of minimally invasive stimulation for a subcortical brain target than previously thought. Human clinical trials using these techniques should reevaluate their methods. Interference stimulation allows significant target selectivity in a peripheral cuff electrode with targets near electrodes. These techniques can allow spatially distinct regions of phasic firing, tonic firing, conduction block, and no effect.
电神经调节仍然是治疗多种神经疾病的有效方法。一种利用多个高频波形干扰来刺激神经的策略，称为时变干扰刺激或干扰电流刺激。最近，作为一种在动物研究和人体临床试验中提高神经刺激最新技术的方法，这种技术引起了人们的极大关注。在这里，我们报告了我们对神经元对这些类型波形的反应的基本特性的研究，包括载波和包络频率、阈值、放电行为以及相位和非对称干扰模式的影响。我们使用大鼠坐骨神经上的袖带电极施加各种干扰信号。我们记录了足底肌肉和股二头肌的肌肉活动，这些肌肉活动是坐骨神经两个主要分支的活动的代表，在目标体积中空间上是不同的。我们测试了基本的募集特性以及空间技术，以选择性地激活任一组肌肉。我们的数据表明，与目前公认的解释相反，神经元根本不提取包络，这些信号的反应可以很好地用具有固定放电阈值的电阻-电容（即积分器）膜来解释。基本干扰技术不会在远离电极的地方改变募集。技术可以产生相位激活和紧张激活/传导阻滞的区域。积分器模型表明，与以前的想法相比，干扰技术对于皮质下脑目标的微创刺激的能力较低。使用这些技术的人体临床试验应重新评估他们的方法。干扰刺激允许在靠近电极的目标的外周袖带电极中具有显著的目标选择性。这些技术可以允许相位放电、紧张放电、传导阻滞和无效应的空间上不同的区域。
