Michel C M, Henggeler B, Brandeis D, Lehmann D
Department of Neurology, University Hospital, Zurich, Switzerland.
Physiol Meas. 1993 Nov;14 Suppl 4A:A21-6. doi: 10.1088/0967-3334/14/4a/004.
A method is described that accounts for multichannel brain field data (EEG) epochs, after transformation into the frequency domain, by a single oscillating dipole source in terms of phase angles. The method produces a potential distribution for each frequency point ('FFT dipole approximation'). These maps can be subjected to conventional equivalent dipole source fittings in terms of amplitudes. We studied the equivalent source locations for the different temporal EEG frequency bands (delta/theta/alpha) in 12 normal subjects during the collection of reports of spontaneous thoughts. Some of the thought reports were classed into two modes, 'visual imagery' and 'abstract', and the associated equivalent source locations during the 2 s immediately prior to these reports were computed. Different equivalent source locations were found for the different spectral components of the EEG, implying that different neural generator populations generate the different frequencies. Further, the different types of spontaneous thought, i.e. different modes of cortical functioning, were found to be associated with the activity of different neuronal generator sources that operated at the same frequency at different source locations.
本文描述了一种方法，该方法通过单个振荡偶极子源的相位角来解释多通道脑电数据（脑电图）在转换到频域后的各个时段。该方法为每个频率点生成一个电位分布（“快速傅里叶变换偶极子近似”）。这些图谱可以在幅度方面进行传统的等效偶极子源拟合。我们在12名正常受试者收集自发思维报告期间，研究了不同时间脑电图频段（δ/θ/α）的等效源位置。一些思维报告被分为“视觉意象”和“抽象”两种模式，并计算了这些报告前2秒内相关的等效源位置。脑电图的不同频谱成分有不同的等效源位置，这意味着不同的神经发生器群体产生不同的频率。此外，发现不同类型的自发思维，即不同的皮层功能模式，与在不同源位置以相同频率运作的不同神经元发生器源的活动有关。
