School of Electrical Engineering and Computer Science, Gwangju Institute of Science & Technology, South Korea.
School of Electrical Engineering and Computer Science, Gwangju Institute of Science & Technology, South Korea.
Brain Stimul. 2019 Mar-Apr;12(2):275-289. doi: 10.1016/j.brs.2018.11.004. Epub 2018 Nov 10.
To address the brain areas and circuits affected by transcranial electrical stimulation (tES), which had been used widely to treat psychiatric and neurological diseases, the stimulus-induced electric field in the cortex was calculated using a head model that reflects anatomical information. To obtain detailed information at the macroscopic and microscopic levels, multi-scale modeling was proposed that integrates the head model with multi-compartmental models of cortical neurons.
Our goal was to use multi-scale modeling to describe the relation between the stimulus-induced electric field and neuronal responses during tES.
We simulated sub- and supra-threshold neuronal responses to stimulus-induced uniform and realistic electric fields. For the realistic electric field, multi-scale models that combined the head model derived from structural MRIs and multi-compartmental models of neurons were constructed. Then, we simulated the steady-state membrane polarization for sub-threshold stimulation and the excitation threshold for supra-threshold stimulation by varying the tES montages. The electric field calculated was decomposed into two orthogonal components, the radial and tangential fields, which were compared to the neuronal responses.
The stimulus-induced electric field depended strongly on stimulus parameters, and neuronal excitability showed a higher correlation with the radial field. We demonstrated that neurons exhibited linear polarization during sub-threshold stimulation depending on the local radial field intensity that resulted in a significant relation regardless of the tES montage. Supra-threshold stimulation showed a stronger relation with the radial field, but rather complex patterns of excitation thresholds depending on neurons' morphological features.
Our results indicated that cortical neurons are affected greatly by the relative direction of the stimulus-induced electric field, which may be a necessary step toward a detailed understanding of tES' potential mechanisms.
为了了解经颅电刺激（tES）影响的大脑区域和回路，该刺激已被广泛用于治疗精神和神经疾病，我们使用反映解剖信息的头部模型来计算皮质中的刺激诱导电场。为了在宏观和微观层面上获得详细信息，提出了多尺度建模，将头部模型与皮质神经元的多室模型相结合。
我们的目标是使用多尺度建模来描述 tES 期间刺激诱导电场与神经元反应之间的关系。
我们模拟了亚阈值和超阈值神经元对刺激诱导的均匀和真实电场的反应。对于真实电场，构建了将头部模型（源自结构 MRI）与神经元的多室模型相结合的多尺度模型。然后，通过改变 tES 组合，模拟亚阈值刺激下的稳态膜极化和超阈值刺激下的兴奋阈值。所计算的电场分解为两个正交分量，即径向场和切向场，并将其与神经元反应进行比较。
刺激诱导的电场强烈依赖于刺激参数，神经元兴奋性与径向场的相关性更高。我们证明，在亚阈值刺激下，神经元表现出线性极化，这取决于导致显著关系的局部径向场强度，而与 tES 组合无关。超阈值刺激与径向场的相关性更强，但取决于神经元形态特征的兴奋阈值存在复杂的模式。
我们的结果表明，皮质神经元受刺激诱导电场的相对方向影响很大，这可能是深入了解 tES 潜在机制的必要步骤。
