Achim A, Richer F, Saint-Hilaire J M
Hôpital Notre-Dame, Montreal, Que., Canada.
Electroencephalogr Clin Neurophysiol. 1991 Sep;79(3):227-40. doi: 10.1016/0013-4694(91)90140-y.
The effects of physiological noise and modelling procedure on spatio-temporal source modelling (STSM) solutions were examined by adding EEG noise (3-4% of total energy) to synthetic signals from 3 dipoles producing topographies that partially cancelled at the surface of an homogeneous sphere. Three patterns of source activation profiles were each associated with two EEG records. The STSM solutions were subjected to statistical tests that detect signal left in the residuals. All models substantially accounted for noise. Essentially correct models left no consistent signal in the residuals, but other statistically acceptable models were also occasionally found. Unambiguous correct solutions were found for moderately correlated source activations. Statistically adequate 2-source and 3-source models were found for the 4 data sets incorporating nearly parallel activations of 2 sources. When all 3 sources had comparable amplitudes, the 2-source models represented compromises containing gross mislocalizations but correct 3-source models were found. When one of the parallel sources was attenuated by 75%, only 2-source models satisfactorily approximated the 2 main sources. The localization errors in the "correct" models ranged from 2.5% to 13% of the sphere radius. Thus, even with a perfect signal propagation model, STSM could at best claim approximate localizations from data containing structured noise.
通过向来自3个偶极子的合成信号添加脑电图噪声（总能量的3-4%）来研究生理噪声和建模过程对时空源建模（STSM）解决方案的影响，这些偶极子产生的地形在均匀球体表面部分抵消。三种源激活轮廓模式分别与两个脑电图记录相关联。对STSM解决方案进行统计测试，以检测残差中留下的信号。所有模型都在很大程度上考虑了噪声。本质上正确的模型在残差中没有留下一致的信号，但偶尔也会发现其他统计上可接受的模型。对于适度相关的源激活，找到了明确的正确解决方案。对于包含两个源几乎平行激活的4个数据集，找到了统计上足够的双源和三源模型。当所有3个源具有可比幅度时，双源模型代表了包含严重定位错误的折衷方案，但找到了正确的三源模型。当其中一个平行源衰减75%时，只有双源模型能令人满意地近似两个主要源。“正确”模型中的定位误差范围为球体半径的2.5%至13%。因此，即使有完美的信号传播模型，STSM最多也只能从包含结构化噪声的数据中获得近似定位。
