Spatial source location analysis of EEG signals for multimodal mental tasks

In order to analyze the cerebral cortex activating by multimodal mental tasks with reading Chinese silently, electroencephalography(EEG) signals related to mental tasks are analyzed using the spatial source location. Firstly, the EEG signals of all electrodes are decomposed into independent components by independent component analysis. Each component can be considered from an equivalent dipole, and its position and direction are calculated in the cerebral cortex. Then, the dipole associated with the mental task is determined by time-frequency analysis. Finally, the differences of dipoles from multimodal mental tasks are analyzed and compared with single mode. After analyzing the results of 10 subjects, the average numbers of dipoles associated with two multimodal mental tasks are respectively calculated as 5 and 4.3, which are more than single mode tasks. The sorting of dipole numbers is consistent with the average classification accuracies of the four tasks. It suggests that more activation of the cerebral cortex is beneficial to improve the accuracy of classification. The validity and rationality of the experiment is also verified.