Trigeminal neuralgia (TN) is a severe neuropathic pain, which has an electric shock-like characteristic. There are some common treatments for this pain such as medicine, microvascular decompression or radio frequency. In this regard, transcranial direct current stimulation (tDCS) is another therapeutic method to reduce pain, which has been recently attracting the therapists’ attention. The positive effect of tDCS on TN was shown in many previous studies. However, the mechanism of the tDCS effect has remained unclear. This study aims to model the neuronal behavior of the main known regions of the brain participating in TN pathways to study the effect of transcranial direct current stimulation. The proposed model consists of several blocks: (1) trigeminal nerve, (2) trigeminal ganglion, (3) PAG (periaqueductal gray in the brainstem), (4) thalamus, (5) motor cortex (M1) and (6) somatosensory cortex (S1). Each of these components is represented by a modified Hodgkin-Huxley (HH) model. The modification of the HH model was done based on some neurological facts of pain sodium channels. The input of the model involves any stimuli to the ‘trigeminal nerve,’ which cause the pain, and the output is the activity of the somatosensory cortex. An external current, which is considered as an electrical current, was applied to the motor cortex block of the model. The results showed that by decreasing the conductivity of the slow sodium channels (pain channels) and applying tDCS over the M1, the activity of the somatosensory cortex would be reduced. This reduction can cause pain relief. The proposed model provided some possible suggestions about the relationship between the effects of tDCS and associated components in TN, and also the relationship between the pain measurement index, somatosensory cortex activity, and the strength of tDCS.

中文翻译：

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修改后的霍奇金-赫胥黎模型显示运动皮层刺激对三叉神经痛网络的影响。


三叉神经痛（TN）是一种严重的神经性疼痛，具有类似电击的特征。对于这种疼痛有一些常见的治疗方法，例如药物、微血管减压或射频。在这方面，经颅直流电刺激（tDCS）是另一种减轻疼痛的治疗方法，最近引起了治疗师的关注。之前的许多研究都显示了 tDCS 对 TN 的积极作用。然而，tDCS 效应的机制仍不清楚。本研究旨在模拟参与 TN 通路的主要已知大脑区域的神经元行为，以研究经颅直流电刺激的效果。所提出的模型由几个模块组成：（1）三叉神经，（2）三叉神经节，（3）PAG（脑干中的导水管周围灰质），（4）丘脑，（5）运动皮层（M1）和（6）体感皮质（S1）。每个组件都由修改后的 Hodgkin-Huxley (HH) 模型表示。 HH 模型的修改是根据疼痛钠通道的一些神经学事实进行的。该模型的输入涉及对“三叉神经”的任何刺激，从而引起疼痛，输出是体感皮层的活动。将外部电流（被视为电流）施加到模型的运动皮层模块。结果表明，通过降低慢钠通道（疼痛通道）的电导率并在 M1 上应用 tD​​CS，体感皮层的活动将会降低。这种减少可以缓解疼痛。 所提出的模型为 tDCS 效果与 TN 相关成分之间的关​​系，以及疼痛测量指数、体感皮层活动和 tDCS 强度之间的关系提供了一些可能的建议。