Topography of Functional Connectivity in Human Multichannel Electroencephalogram during Second Language Processing

We analyze the topography of nonlinear functional connectivity in the EEG of two groups of German-native speakers, divided according to their English proficiency level (high or low), when listening to one text in German and one in English. Global interdependence was assessed in full-band EEG by means of an index of multivariate correlation derived from the normalized cross-mutual information between every two electrodes within each region of interest (ROI): three interhemispheric (frontal, centro-temporal and parietooccipital) and two intrahemispheric ones (left and right hemisphere). The results show clear topographic differences between the interhemispheric ROIs, but no differences between the intrahemispheric ROIs. Furthermore, there are also differences in language processing that depend on the proficiency level. We discuss these results and their implication along with recent findings on phase synchronization in the gamma band during second language processing.