[Ontogenetic formation of stereognosis brain mechanism (EEG study)]

In this study the age specificity of inter- and intrahemispheric relations during stereognostic task (tactile identification of predetermined chess-like pieces with right or left hand) in adults and children of 5-6, 7-8 an 9-10 years old is considered. The combined pattern of cortical interactions was revealed in adults. Its appeared in significant increasing (compared to baseline) of interhemispheric EEG relations along with increasing of system interactions of anterior and posterior cortex areas bioelectrical activity. This combined pattern is observed both in case of using EEG coherence and correlation analysis. In children interhemispheric EEG relations increasing is appeared already in 5-6 years (maximum in 7-8 yo.), whereas increasing of EEG relations in fronto-occipital direction expanses gradually with age, and only in age 9-10 approaches to definitive level, typical for adults. The data obtained evidence the gradually formation in postnatal ontogenesis of central mechanisms of such important function--stereognosis. Our results suppose that brain mechanisms of right (leading) hand stereognostic activity maturate earlier than left (nonleading) hand activity. Heterochronic involving in stereognostic activity of inter- and intrahemispheric relations can be closely related with gradual and heterochronic processes of commissural and associative hemispheric tracts mielinization.