Expression of Hemispheric Asymmetry and Psychological Type in the EEG Traveling Wave

Spontaneous EEG patterns were recorded from 16 derivations in the parieto-occipital area over 2 min for subjects in the resting state with the eyes closed. Further, computer analysis of the current pattern of EEG phase relationships between all derivations was conducted, followed by visualization in real time of the trajectory and velocity of the traveling EEG wave as a computerized animation over the contour of the head. On the basis of visual observations and objective statistical analysis, we found consistent individual characteristics of the time course and trajectory of the traveling wave, which were compared to the results of psychological testing of the subjects. Most characteristic were modulations of the electric activity (traveling) in the transverse direction (from left to right and from right to left) and along the diagonal from the left anterior to the right posterior areas. Distinct groups of subjects were found with the predominance of one or the other trajectory type. The specific direction of the diagonal traveling was significantly correlated with the level of extroversion of the subject: extroverts were characterized by traveling of electric waves from the occiput forward to the vertex along the diagonal indicated, whereas for introverts, traveling from the vertex to the occiput was typical.