Age-related characteristics of the formation of neurophysiological mechanisms of the phonemic, grammatical, and semantic linguistic levels

Abstract

The structure of regional interactions of brain bioelectric potentials has been studied during performance by adults (n = 18) and children aged five to six (n = 15) and eight to nine years (n = 17) of three analytical verbal tasks: recognition of a given phoneme in the context of auditory presented words and recognition of grammatical and semantic mistakes in auditory presented sentences. According to the data of cross-correlation and coherent EEG analyses, adults and, to a lesser extent, children of both age groups showed a noticeable intensification of interhemispheric interaction during the performance of all three tasks, especially between temporal areas, with relatively minor changes in ipsilateral EEG relations. Children were shown to have elements of immaturity of neurophysiological mechanisms underlying various aspects of the language function, such as the analysis of the grammatical formation of a verbal utterance and the semantic content of a phrase. The results also suggest that the level of maturation of neurophysiological mechanisms underlying phonemic analysis is somewhat higher at these age stages than the level of maturity of central mechanisms responsible for the analysis of the semantic content and grammatical construction of a phrase. Quantitative comparison of the patterns of spatial interaction of cortical bioelectric potentials recorded during the performance of the tasks related to different linguistic levels showed a high degree of their statistical similarity for each of the age groups. The findings confirm the assumption that the distributive central maintenance of different linguistic levels is based on topologically close constellations of interacting cortical areas and on similar organization of their regional interactions.