Genetic features of the spatial organization of the human cerebral cortex.

The within-pair similarity of the topographical maps of the spatial synchronization of the cerebral cortical potentials was studied in 11 pairs of monozygotic twins and 20 genetically unrelated subjects in the resting state and during four types of intellectual activity. It was demonstrated that the degree of similarity of the topographical maps is higher in the resting state in the monozygotic twins than in the genetically unrelated subjects. No frequency band of the EEG which exerts a special influence on the formation of the high degree of similarity of the spatial synchronization of the potentials was found. The maximal similarity in the topographical maps of the monozygotic twins is observed in the anterior regions of the left hemisphere and in the temporoparietal regions of the right. Differences between groups are recorded in both regions; however they are especially distinct in the right hemisphere. The data obtained make it possible to draw an inference regarding the influence of a genetic factor not only on individual components of the EEG (which had been previously demonstrated by a number of authors), but also on the systemic organization of the cortical processes. The right-hemispheric activity apparently relates to the most controllable genetic processes. The results of the analysis of the similarity of topographical maps during various types of activity confirm this: the coefficient of similarity reaches the level of significance in the majority of pairs of monozygotic twins only in a “right-hemispheric” test (simultaneous analysis of nonverbal material).