Department of Electronics and Electromagnetism, Universidad de Sevilla , Seville, Spain.
Department of Applied Physics, Universidad de Sevilla , Seville, Spain.
Electromagn Biol Med. 2020 Oct 1;39(4):310-315. doi: 10.1080/15368378.2020.1793172. Epub 2020 Jul 15.
Transcranial static magnetic stimulation is a novel noninvasive method of reduction of the cortical excitability in certain neurological diseases that makes use of static magnetic fields generated by permanent magnets. By contrast, ordinary transcranial magnetic stimulation makes use of pulsed magnetic fields generated by strong currents. Whereas the physical principle underlying ordinary transcranial magnetic stimulation is well known, that is, the Faraday´s law, the physical mechanism that explains the interaction between neurons and static magnetic fields in transcranial static magnetic stimulation remains unclear. In the present work, it is discussed the possibility that this mechanism might be the Lorentz force exerted on the ions flowing along the membrane channels of neurons. The overall effect of the static magnetic field would be to introduce an additional friction between the ions and the walls of the membrane channels, thus reducing its conductance. Calculations performed by using a Hodgkin-Huxley model demonstrate that even a slight reduction of the conductance of the membrane channels can lead to the suppression of the action potential, thus inhibiting neuronal activity.
经颅静磁刺激是一种利用永磁体产生的静磁场来降低某些神经疾病皮质兴奋性的新型无创方法。相比之下，普通经颅磁刺激则利用强电流产生的脉冲磁场。虽然普通经颅磁刺激的物理原理众所周知，即法拉第定律，但解释经颅静磁刺激中神经元与静磁场相互作用的物理机制尚不清楚。在本工作中，讨论了这种机制可能是洛伦兹力作用于沿神经元膜通道流动的离子的可能性。静磁场的整体效果将在离子和膜通道壁之间引入额外的摩擦力，从而降低其电导。使用 Hodgkin-Huxley 模型进行的计算表明，即使膜通道电导略有降低也可能导致动作电位抑制，从而抑制神经元活动。
