Impact of uncertain head tissue conductivity in the optimization of transcranial direct current stimulation for an auditory target.
Impact of uncertain head tissue conductivity in the optimization of transcranial direct current stimulation for an auditory target.
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DOI：
10.1088/1741-2560/12/4/046028
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发表时间：
2015-08
影响因子：
4
通讯作者：
Wolters CH
中科院分区：
文献类型：
--
作者：
Schmidt C;Wagner S;Burger M;Rienen Uv;Wolters CH
经颅直流电刺激（tDCS）是一种非侵入性的脑刺激技术，以改变神经兴奋性。使用多阵列tDCS，我们调查的最佳电极配置的听觉皮层刺激的个体间不同的头部组织的电导率分布的影响。为了量化最佳电极配置的不确定性，基于隔室皮肤、颅骨、灰质和白色物质的不确定电导率分布，使用模型解的多变量广义多项式混沌（gPC）展开。随机测量，概率密度函数，和感兴趣的量的灵敏度进行了研究，为每个电极和电流密度在目标与所得的刺激协议可视化的头部表面上。我们证明，优化的刺激方案仅由几个有源电极组成，阳极的刺激幅度具有可容忍的偏差。然而，在补偿阴极的刺激方案中，可以注意到电导率曲线的不确定性顺序的大偏差。关于这些主要刺激电极，刺激方案对颅骨电导率的不确定性最敏感。最后，在听觉皮层目标区域中的电流密度幅值是阈上的概率低于50%。结果表明，不确定的电导率分布在计算模型的tDCS可以有很大的影响预测的最佳刺激方案刺激的听觉皮层。在这项研究中进行的调查提出了一种可能性，预测提供一个优化的电极系统的治疗效果的概率，为未来的听觉临床和实验程序的tDCS应用。
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique to modify neural excitability. Using multi-array tDCS, we investigate the influence of inter-individually varying head tissue conductivity profiles on optimal electrode configurations for an auditory cortex stimulation. In order to quantify the uncertainty of the optimal electrode configurations, multi-variate generalized Polynomial Chaos (gPC) expansions of the model solutions are used based on uncertain conductivity profiles of the compartments skin, skull, gray matter, and white matter. Stochastic measures, probability density functions, and sensitivity of the quantities of interest are investigated for each electrode and the current density at the target with the resulting stimulation protocols visualized on the head surface. We demonstrate that the optimized stimulation protocols are only comprised of a few active electrodes, with tolerable deviations in the stimulation amplitude of the anode. However, large deviations in the order of the uncertainty in the conductivity profiles could be noted in the stimulation protocol of the compensating cathodes. Regarding these main stimulation electrodes, the stimulation protocol was most sensitive to uncertainty in skull conductivity. Finally, the probability that the current density amplitude in the auditory cortex target region is supra-threshold was below 50%. The results suggest that an uncertain conductivity profile in computational models of tDCS can have a substantial influence on the prediction of optimal stimulation protocols for stimulation of the auditory cortex. The investigations carried out in this study present a possibility to predict the probability of providing a therapeutic effect with an optimized electrode system for future auditory clinical and experimental procedures of tDCS applications.