Correlation and coherence analyses of multichannel EEG recordings from 18 subjects (mean age 25 years) were used for investigating the reorganization of systemic interactions between bioelectric potentials of the cortical areas of both hemispheres (20 EEG derivations) during verbal–mental activity connected with generating verbal units from simpler components. When generating words from auditory presented phonemes or sentences from a set of words, the subjects exhibited specific changes in the spa-
tial structure of the statistical relationships in the EEG, with a significant increase in the hemispheric interactions. During performance of both tasks, the changes in the hemispheric interactions were most pronounced in the temporal, temporo-parieto-occipital (TPO), inferofrontal, and occipital areas of both hemi
spheres. Phonemic synthesis was associated with a more marked increase in the contralateral interactions in the left hemisphere, and generating sentences from words, in the right hemisphere. The coherence analysis of the EEG showed the greatest changes in the
∆, θ, and β frequency bands, with rather slight changes in the α
frequency band. For all frequency bands, changes in the EEG coherences were the greatest in Wernicke’s and the TPO areas during performance of both tasks, especially during the phone-
mic synthesis. These findings suggest that neurophysiological processes underlying mental generation of words
and sentences require coordinated activity of the left and right hemispheres, which is accompanied by an increase in the interhemispheric interactions in the EEG, especially in the temporal, inferofrontal, and TPO areas.