[The ontogenetic characteristics of the functional organization of the cerebral hemispheres in selective attention: perceptual task expectancy].

EEG characteristics of brain organization of selective attention were studied in children (n = 10, 9 years old) during task expectancy with special reference to hemisphere specialization. Children had to distinguish lateralized signals according to their duration. Warning stimulus pointed to the modality of the task (tactile, auditory, visual). Intra-hemispheric alpha-coherence was evaluated in the prestimulus period with the following statistical analysis of the individual data. The main distinctions of the brain functional organization during expectancy between children and adults consisted in less pronounced selectivity of EEG changes in the left hemisphere and in existence of modal specificity in the right hemisphere in children as compared to adults. Thus, the functional specialization of the hemispheres in children is not yet completely developed. Brain hemispheres of children partly share functions rather than complement each other.