Research on High Spatial Resolution SSVEP Signal Acquisition and Analysis Based on Scalp Laplace EEG Electrodes

‍ ‍EEG signals are widely used due to their advantages of high temporal resolution and convenience. However， the low spatial resolution of EEG signals limits the effectiveness of EEG application. Laplacian filtering methods have been proved to improve the spatial resolution of body surface potentials. The traditional Laplace EEG research usually utilize algorithms to estimate Laplace potentials through the disc electrode arrays. However， the distance between the disc electrodes usually are far away， which makes the estimation results of this method less accurate. This study proposed to use Laplace EEG electrode to improve the spatial resolution of EEG signals， which was verified by both simulation experiments and real human EEG experiments. The simulation results show that the spatial resolution of the Laplace electrode is about 41.4% higher than that of the traditional disc electrode. The results of EEG experiments show when the visual cortices of left and right hemispheres simultaneously produced steady-state visual evoked potentials（SSVEPs）， the left and right SSVEP sources could be clearly distinguished from Laplace EEG signals but not from the traditional EEG signals. These results indicate that the Laplace EEG electrode proposed in this study can effectively improve the spatial resolution of EEG， and the Laplace EEG is expected to achieve more accurate EEG source location.