Common Interferences Removal from Dense Multichannel EEG Using Independent Component Decomposition

Figure 7

Comparison of the index of global coherence between the original and the processed signals. (The horizontal axis represents the frequency, and the vertical axis represents the index of global coherence. In the original data, all human subjects, i.e., (a), (b), (f), and (g), present high coherences in both low frequency band and high frequency band, which indicates a universal conductance induced consistency on scalp. However, as for the processed data, the high coherences in that two frequency bands are both suppressed while a coherence peak in mu rhythms (the green shade area) becomes prominent except for subject #b. It implies that although we did not mean to filter the specific frequency, the spurious high coherences caused by the common interferences are greatly alleviated. We cannot observe mu coherence in the artificial signals, i.e., (c), (d), and (e))

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