Spatial Synchronization of Cortical Electrical Activity at Different Stages of a Visual Set in 8-Year-Old Children with Different Levels of Development of the Frontothalamic Selective Attention System

Children of early school age (8.0 ± 0.1 years) were separated on the basis of EEG characteristics into the following groups: 1) those with normal development of the frontothalamic selective attention system (n = 21) and 2) those with functional immaturity of the frontothalamic system due to delays in its development (n = 29). The Uznadze paradigm was used to form a set to nonverbal visual stimuli (circles of different sizes). The set was rigid in most group 2 children. The coherence of cortical electrical potentials in the theta, alpha, and beta ranges recorded from the frontal, central, temporal, parietal, and occipital areas was analyzed. Intergroup differences were most marked at the set actualization stage in children with plastic sets: the coherence of potentials between the anterior and posterior zones was significantly more marked in subjects with immature frontothalamic systems than in the “normal” group. The relationship between the level of coherence of potentials with set plasticity was more defined in the “frontothalamic” group than in the control group. Rigid sets were associated with significantly lower levels of coherence of potentials in all ranges as compared with the baseline EEG with the eyes open. The increase in the coherence of theta potentials on set actualization occurring mainly in the right hemisphere in the “frontothalamic” group was interpreted as a measure of the compensatory increase in the role of the corticohippocampal system to support set plasticity.