Spatial and temporal resolutions of EEG: Is it really black and white? A scalp current density view.
Spatial and temporal resolutions of EEG: Is it really black and white? A scalp current density view.
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DOI：
10.1016/j.ijpsycho.2015.05.004
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发表时间：
2015-09
期刊：
影响因子：
--
通讯作者：
Vidal F
中科院分区：
文献类型：
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作者：
Burle B;Spieser L;Roger C;Casini L;Hasbroucq T;Vidal F
在各种脑成像技术中，脑电图（EEG）被认为具有良好的时间分辨率，但空间分辨率较差。在这里，我们认为，传统的（头皮电位）EEG的实际时间分辨率被高估，和体积传导，EEG的空间分辨率差的主要原因，也扭曲了恢复的时间过程中的底层源在头皮水平，从而降低了EEG的实际时间分辨率。虽然电流源密度（CSD）估计，通过表面拉普拉斯（SL）计算，是众所周知的，以显着减少体积传导效应，从而提高EEG的空间分辨率，其积极的影响EEG的时间分辨率是少得多的认可。在两个模拟研究中，我们首先展示了体积传导和参考电极如何扭曲头皮电位时间过程，以及SL变换如何提供更好的时空描述。然后，我们在两个经验数据集上验证了类似的效果。我们展示了头皮电位的时间过程是如何错误估计相关脑事件的延迟的，并且CSD提供了更丰富、更准确的脑活动时空动态的视图。我们研究了体积传导对EEG时间分辨率的影响。模拟结果显示，头皮电位数据的时间分辨率下降。电流源密度允许很好地恢复潜在的时间过程。这些影响在两个经验数据集上显示。讨论了CSD等去模糊方法的重要性。
Among the different brain imaging techniques, electroencephalography (EEG) is classically considered as having an excellent temporal resolution, but a poor spatial one. Here, we argue that the actual temporal resolution of conventional (scalp potentials) EEG is overestimated, and that volume conduction, the main cause of the poor spatial resolution of EEG, also distorts the recovered time course of the underlying sources at scalp level, and hence degrades the actual temporal resolution of EEG. While Current Source Density (CSD) estimates, through the Surface Laplacian (SL) computation, are well known to dramatically reduce volume conduction effects and hence improve EEG spatial resolution, its positive impact on EEG temporal resolution is much less recognized. In two simulation studies, we first show how volume conduction and reference electrodes distort the scalp potential time course, and how SL transform provides a much better spatio-temporal description. We then exemplify similar effects on two empirical datasets. We show how the time courses of the scalp potentials mis-estimate the latencies of the relevant brain events and that CSD provides a much richer, and much more accurate, view of the spatio-temporal dynamics of brain activity. We investigated the impact of volume conduction on the temporal resolution of EEG. Simulations revealed a degraded temporal resolution of scalp potential data. Current Source Density allows to nicely recover the underlying time courses. These effects are shown on two empirical datasets. The importance of deblurring methods, such as CSD, is discussed.