Analysis and optimization of pulse dynamics for magnetic stimulation.
Analysis and optimization of pulse dynamics for magnetic stimulation.
复制标题
DOI：
10.1371/journal.pone.0055771
复制
发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Weyh T
中科院分区：
文献类型：
--
作者：
Goetz SM;Truong CN;Gerhofer MG;Peterchev AV;Herzog HG;Weyh T
磁刺激是大脑研究中的标准工具，并在神经病学，精神病学和康复中发现了重要的临床应用。而线圈的设计和空间场的属性已在文献中进行了深入的研究，该领域的时间动态受到较少的关注。通常，磁场波形是由可用的设备电路拓扑结构确定的，而不是考虑什么对神经刺激最佳。本文分析和优化的波形动力学使用的非线性模型的哺乳动物轴突。优化目标是使脉冲能量损失最小。能量损失导致功耗和发热，这是磁刺激的主要限制。该优化方法是基于一个混合的全局-局部方法。为了保证数值稳定性，在有限的参数空间中定义了描述连续波形的不同坐标系。优化结果表明，有波形的效率大大高于传统的脉冲形状。进一步分析了一类最优脉冲。虽然这些波形的线圈电压分布几乎是矩形的，但相应的电流形状呈现出独特的特征，例如在主脉冲之前的缓慢的低幅度第一相位，并减少了损耗。对应于不同最大电压的这类波形的代表通过非线性变换链接。然而，主要阶段只与时间成比例。与传统的磁刺激脉冲一样，较短的脉冲导致较低的能量损失，但需要比较长脉冲更高的线圈电压。
Magnetic stimulation is a standard tool in brain research and has found important clinical applications in neurology, psychiatry, and rehabilitation. Whereas coil designs and the spatial field properties have been intensively studied in the literature, the temporal dynamics of the field has received less attention. Typically, the magnetic field waveform is determined by available device circuit topologies rather than by consideration of what is optimal for neural stimulation. This paper analyzes and optimizes the waveform dynamics using a nonlinear model of a mammalian axon. The optimization objective was to minimize the pulse energy loss. The energy loss drives power consumption and heating, which are the dominating limitations of magnetic stimulation. The optimization approach is based on a hybrid global-local method. Different coordinate systems for describing the continuous waveforms in a limited parameter space are defined for numerical stability. The optimization results suggest that there are waveforms with substantially higher efficiency than that of traditional pulse shapes. One class of optimal pulses is analyzed further. Although the coil voltage profile of these waveforms is almost rectangular, the corresponding current shape presents distinctive characteristics, such as a slow low-amplitude first phase which precedes the main pulse and reduces the losses. Representatives of this class of waveforms corresponding to different maximum voltages are linked by a nonlinear transformation. The main phase, however, scales with time only. As with conventional magnetic stimulation pulses, briefer pulses result in lower energy loss but require higher coil voltage than longer pulses.
登录
查看更多内容
影响因子：
4.6
作者：
Hsu, KH;Nagarajan, SS;Durand, DM
通讯作者：
Durand, DM
影响因子：
4.7
作者：
Kammer, T;Beck, S;Topka, H
通讯作者：
Topka, H
影响因子：
5.7
作者：
Butson, Christopher R.;Cooper, Scott E.;McIntyre, Cameron C.
通讯作者：
McIntyre, Cameron C.
影响因子：
4
作者：
Foutz TJ;McIntyre CC
通讯作者：
McIntyre CC
影响因子：
5.5
作者：
Di Lazzaro, V;Oliviero, A;Rothwell, JC
通讯作者：
Rothwell, JC