A rapidly growing number of neuromagnetic studies focus on the analysis of auditory steady-state responses (ASSR) in relation to a diverse array of factors including age, selective attention, and presence of psychopathology. The objectives of these studies require accurate spatio-temporal estimation of the underlying neural generators, a challenging task due to the relatively low signal strength and high correlation between bilateral auditory cortical sources. This paper evaluates the performance of two beamforming schemes that can potentially overcome such difficulties: 1) the linearly constrained minimum variance beamformer with partial sensor coverage (LCMV-PSC), and 2) the multiple constrained minimum-variance beamformer with coherent source region suppression (MCMV-CSRS). Simulation experiments are conducted to assess the impact of source parameters on the reconstruction accuracy. The results indicate that the LCMV-PSC method is prone to localization errors that essentially occur along medio-lateral directions, increase with source depth, and are associated to amplitude and phase distortions of the estimated time courses of activity. Comparatively, the MCMV-CSRS method exhibits precise localization and minimal amplitude and phase distortion for a broad range of relative interferer's positions within the suppression region. The results from the numerical experiments are validated on real magnetoencephalographic (MEG) data collected from a 40-Hz ASSR paradigm.

译文

越来越多的神经磁学研究专注于分析听觉稳态反应 (ASSR) 与各种因素有关,包括年龄,选择性注意和精神病理学的存在。这些研究的目标需要对潜在的神经发生器进行准确的时空估计,这是一项艰巨的任务,因为信号强度相对较低且双边听觉皮层源之间的相关性较高。本文评估了两种可能克服此类困难的波束形成方案的性能: 1) 具有部分传感器覆盖的线性约束最小方差波束形成器 (lcmv-psc),以及2) 具有相干源区抑制的多重约束最小方差波束形成器 (mcmv-csrs)。进行了仿真实验,以评估源参数对重建精度的影响。结果表明,lcmv-psc方法容易发生定位误差,这些误差基本上沿中横向方向发生,随着源深度的增加而增加,并且与估计的活动时间过程的幅度和相位失真有关。相比之下,MCMV-CSRS方法在抑制区域内的相对干扰源位置范围很广,表现出精确的定位以及最小的幅度和相位失真。数值实验的结果已在从40Hz ASSR范例收集的真实脑磁图 (MEG) 数据上进行了验证。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录