Reorganization of interhemispheric interactions during verbal-mental activity aimed at synthesis of words and sentences

Ontogenetic Development of Neurophysiological Mechanisms Underlying Language Processing

“…A significant increase of the interhemispheric Evolutionary Physiology and Biochemistry -Advances and Perspectivesrelations was observed during phoneme recognition, especially in theta and delta frequency bands between temporal areas of both hemispheres [44] (Figure 2). During word composition task, changes in the hemispheric interactions were most pronounced in the temporal, especially Wernike's and temporo-parieto-occipital areas of both hemispheres [2] (Figure 2). A remarkable increase in regional interactions in the occipital areas accompanied by a decrease in interactions in frontal areas was observed during controlled word association.…”

“…The rate of composing words from sounds was much slower in children than the rate of composing sentences from words. This may be due to the children preschool age, and they are still unable to read and write, so they do not operate with visual images while inventing words, comparing to adults [2].…”

“…The other line of our research addresses the neurophysiological mechanisms underlying the maintenance of mental speech activity associated with the synthesis of speech units from elementary components (mental composing words from a set of phonemes and composing sentences from a set of words) in healthy adults [2] and children aged 5-6 years [4]. During the mental composition of words from an auditory presented set of phonemes (phonemic synthesis) or sentences from a set of words, the adults exhibited specific changes in the spatial structure of the statistical EEG relationships with a significant increase in the interhemispheric interactions.…”

“…An appropriate way to study patterns of cortical interactions is analysis of the spatiotemporal organization of brain activity oscillations. Currently, it is of no doubt that language processing relies on a widespread network of brain regions [1][2][3][4][5][20][21][22][23][24][25][26]. Great importance is also attached to the role of cortical networks and functional connections between different parts of the brain, in both adults and children [21,22,[27][28][29][30][31][32][33].…”

“…A study of the functional interaction between various parts of the cerebral cortex (so-called functional connectivity) is of fundamental importance for understanding the neural basis of cognition [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. A growing number of studies that have appeared in the last decade testify the renewed interest in functional interactions among different brain parts, in both the background state and under cognitive activity [13,15].…”