Kashyap Rajan, Bhattacharjee Sagarika, Arumugam Ramaswamy, Oishi Kenichi, Desmond John E, Chen Sh Annabel
Centre for Research and Development in Learning (CRADLE), Nanyang Technological University, Singapore.
Equal Contribution.
J Neural Eng. 2020 Oct 14;17(5):056034. doi: 10.1088/1741-2552/aba6dc.
Transcranial Direct Current Stimulation (tDCS) is a technique where a weak current is passed through the electrodes placed on the scalp. The distribution of the electric current induced in the brain due to tDCS is provided by simulation toolbox like Realistic volumetric Approach based Simulator for Transcranial electric stimulation (ROAST). However, the procedure to estimate the total current density induced at the target and the intermediary region of the cortex is complex. The Systematic-Approach-for-tDCS-Analysis (SATA) was developed to overcome this problem. However, SATA is limited to standardized (MNI152) headspace only. Here we develop individual-SATA (i-SATA) to extend it to individual head.
T1-weighted images of 15 subjects were taken from two Magnetic Resonance Imaging scanners of different strengths. Across the subjects, the montages were simulated in ROAST. i-SATA converts the ROAST output to Talairach space. The x, y and z coordinates of the anterior commissure (AC), posterior commissure (PC), and Mid-Sagittal (MS) points are necessary for the conversion. AC and PC are detected using the acpcdetect toolbox. We developed a method to determine the MS in the image and cross-verified its location manually using BrainSight®.
Determination of points with i-SATA is fast and accurate. The i-SATA provided estimates of the current-density induced across an individual's cortical lobes and gyri as tested on images from two different scanners.
Researchers can use i-SATA for customizing tDCS-montages. With i-SATA it is also easier to compute the inter-individual variation in current-density across the target and intermediary regions of the brain. The software is publicly available.
经颅直流电刺激（tDCS）是一种将弱电流通过置于头皮上的电极的技术。由于tDCS在大脑中感应产生的电流分布由诸如基于现实容积法的经颅电刺激模拟器（ROAST）这样的模拟工具箱提供。然而，估计在目标区域和皮质中间区域感应产生的总电流密度的过程很复杂。为克服这一问题，开发了tDCS分析系统方法（SATA）。然而，SATA仅局限于标准化（MNI152）头空间。在此，我们开发了个体SATA（i-SATA）以将其扩展到个体头部。
从两台不同强度的磁共振成像扫描仪获取了15名受试者的T1加权图像。在所有受试者中，在ROAST中模拟了电极配置。i-SATA将ROAST输出转换为Talairach空间。转换需要前连合（AC）、后连合（PC）和中矢状（MS）点的x、y和z坐标。使用acpcdetect工具箱检测AC和PC。我们开发了一种在图像中确定MS的方法，并使用BrainSight®手动交叉验证其位置。
使用i-SATA确定点快速且准确。如在来自两台不同扫描仪的图像上所测试的那样，i-SATA提供了在个体皮质叶和脑回上感应产生的电流密度的估计值。
研究人员可以使用i-SATA来定制tDCS电极配置。使用i-SATA也更容易计算大脑目标区域和中间区域电流密度的个体间差异。该软件可公开获取。
