优化多通道经颅电刺激中多个目标的电场强度。
Optimizing the electric field strength in multiple targets for multichannel transcranial electric stimulation.
机构信息
Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.
Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark.
出版信息
J Neural Eng. 2021 Feb 11;18(1). doi: 10.1088/1741-2552/abca15.
Most approaches to optimize the electric field pattern generated by multichannel transcranial electric stimulation (TES) require the definition of a preferred direction of the electric field in the target region(s). However, this requires knowledge about how the neural effects depend on the field direction, which is not always available. Thus, it can be preferential to optimize the field strength in the target(s), irrespective of the field direction. However, this results in a more complex optimization problem.We introduce and validate a novel optimization algorithm that maximizes focality while controlling the electric field strength in the target to maintain a defined value. It obeys the safety constraints, allows limiting the number of active electrodes and allows also for multi-target optimization.The optimization algorithm outperformed naïve search approaches in both quality of the solution and computational efficiency. Using the amygdala as test case, we show that it allows for reaching a reasonable trade-off between focality and field strength in the target. In contrast, simply maximizing the field strength in the target results in far more extended fields. In addition, by maintaining the pre-defined field strengths in the targets, the new algorithm allows for a balanced stimulation of two or more regions.The novel algorithm can be used to automatically obtain individualized, optimal montages for targeting regions without the need to define preferential directions. It will automatically select the field direction that achieves the desired field strength in the target(s) with the most focal stimulation pattern.
大多数优化多通道经颅电刺激(TES)产生的电场模式的方法都需要定义目标区域(多个)中电场的首选方向。然而,这需要了解神经效应如何随场方向而变化,而这并不总是可行的。因此,优先优化目标中的场强,而不考虑场方向可能更为有利。然而,这会导致更复杂的优化问题。
我们引入并验证了一种新的优化算法,该算法在控制目标中的电场强度以保持定义值的同时最大化聚焦度。它遵守安全约束,允许限制活动电极的数量,也允许多目标优化。
在解决方案的质量和计算效率方面,优化算法都优于盲目搜索方法。使用杏仁核作为测试案例,我们表明它可以在聚焦度和目标中的场强之间实现合理的权衡。相比之下,简单地最大化目标中的场强会导致场强扩展得更远。此外,通过保持目标中预定义的场强,新算法允许对两个或更多区域进行平衡刺激。
该新算法可用于自动为无需要定义首选方向的目标区域获得个性化的最优刺激配置。它将自动选择实现目标中所需场强的最佳场方向,同时实现最聚焦的刺激模式。