Huang Yu, Thomas Chris, Datta Abhishek, Parra Lucas C
Annu Int Conf IEEE Eng Med Biol Soc. 2018 Jul;2018:3545-3548. doi: 10.1109/EMBC.2018.8513034.
Transcranial direct current stimulation (tDCS) aims to deliver weak electric current into the brain to modulate neural activities. Based on the volume conductor model of the head, optimization algorithm can be used to determine a specific montage of high-definition electrodes on the scalp to achieve targeted stimulation. However, simultaneous targeting for multiple disconnected regions can rarely be found in the literature. Here we attempted to provide an integrated solution for optimized tDCS to target multiple brain regions (either a single point or brain structures). By improving the "maxintensity" routine previously published in [1], we are able to target two regions of interest (ROI) in the brain simultaneously.For ROIs more than two, we show that the "max-focality" algorithm using weighted least-square in [1] can be further improved by putting the L1-norm constraint on the stimulation current as apenalty term into the cost function. Up to five ROIs can be targeted at the same time without violating the safety criteria. Further analysis shows that, for multiple targets, a trade-off exists between targeting accuracy and the number of electrodes needed. We implemented all these algorithms in Soterix software HD-Targets.
经颅直流电刺激（tDCS）旨在将弱电流输送到大脑中以调节神经活动。基于头部的容积导体模型，可使用优化算法来确定头皮上高清电极的特定组合，以实现靶向刺激。然而，在文献中很少能找到针对多个不相连区域的同时靶向方法。在此，我们试图为优化tDCS以靶向多个脑区（单个点或脑结构）提供一种综合解决方案。通过改进先前在[1]中发表的“最大强度”程序，我们能够同时靶向大脑中的两个感兴趣区域（ROI）。对于两个以上的ROI，我们表明，通过将刺激电流的L1范数约束作为惩罚项纳入成本函数，[1]中使用加权最小二乘法的“最大聚焦度”算法可以进一步改进。在不违反安全标准的情况下，最多可同时靶向五个ROI。进一步分析表明，对于多个靶点，在靶向精度和所需电极数量之间存在权衡。我们在Soterix软件HD-Targets中实现了所有这些算法。
