Plovie Tom, Schoeters Ruben, Tarnaud Thomas, Joseph Wout, Tanghe Emmeric
WAVES, Department of Information Technology, Ghent University, Ghent, Belgium.
4Brain, Department of Head and Skin, Ghent University, Ghent, Belgium.
Bioelectromagnetics. 2025 Jan;46(1):e22522. doi: 10.1002/bem.22522. Epub 2024 Aug 26.
In temporal interference (TI) stimulation, neuronal cells react to two interfering sinusoidal electric fields with a slightly different frequency ( , in the range of about 1-4 kHz, in the range of about 1-100 Hz). It has been previously observed that for the same input intensity, the neurons do not react to a purely sinusoidal signal at or . This study seeks a better understanding of the largely unknown mechanisms underlying TI neuromodulation. To this end, single-compartment models are used to simulate computationally the response of neurons to the sinusoidal and TI waveform. This study compares five different neuron models: Hodgkin-Huxley (HH), Frankenhaeuser-Huxley (FH), along with leaky, exponential, and adaptive-exponential integrate-and-fire (IF). It was found that IF models do not entirely reflect the experimental behavior while the HH and FH model did qualitatively replicate the observed neural responses. Changing the time constants and steady state values of the ion gates in the FH model alters the response to both the sinusoidal and TI signal, possibly reducing the firing threshold of the sinusoidal input below that of the TI input. The results show that in the modified (simplified) model, TI stimulation is not qualitatively impacted by nonlinearities in the current-voltage relation. In contrast, ion channels have a significant impact on the neuronal response. This paper offers insights into neuronal biophysics and computational models of TI stimulation.
在时间干扰（TI）刺激中，神经元细胞对两个频率略有不同的干扰正弦电场作出反应（ ， 在约1 - 4kHz范围内， 在约1 - 100Hz范围内）。此前已经观察到，对于相同的输入强度，神经元对 或 的纯正弦信号不产生反应。本研究旨在更好地理解TI神经调节背后很大程度上未知的机制。为此，使用单室模型通过计算模拟神经元对正弦和TI波形的反应。本研究比较了五种不同的神经元模型：霍奇金 - 赫胥黎（HH）模型、弗兰肯海泽 - 赫胥黎（FH）模型，以及漏电、指数和自适应指数积分发放（IF）模型。结果发现，IF模型并未完全反映实验行为，而HH和FH模型在定性上复制了观察到的神经反应。改变FH模型中离子门的时间常数和稳态值会改变对正弦和TI信号的反应，可能会使正弦输入的发放阈值低于TI输入的发放阈值。结果表明，在修改后的（简化）模型中，TI刺激在定性上不受电流 - 电压关系中非线性的影响。相比之下，离子通道对神经元反应有显著影响。本文为TI刺激的神经元生物物理学和计算模型提供了见解。
