[Spectral power of theta and alpha EEG-bands in preschool children with different level of set plasticity].

Spectral power of theta and alpha EEG-bands at different stages of visual set was studied in 5-7-year-old children. Children with a plastic set had greater alpha-band spectral power values than children with a rigid set. At set formation stage children with a rigid set displayed an increase of theta-band EEG-power, which is a manifestation of "immature" arousal reaction. Children with a plastic set displayed at set formation stage an increase of alpha-band spectral power in bilateral occipital brain areas. Dynamics of EEG spectral power differed in children before and after 6 years of age. At set formation stage 5-6-year-olds displayed an above-mentioned "immature" arousal reaction, and 6-7-year-olds--an increase of alpha-band spectral power in occipital brain areas. At set actualization stage 6-7-year-olds displayed an increase of alpha-band spectral power in right posterior brain areas. At set extinction in this group a bilateral decrease of alpha-band spectral power in mid-frontal areas was observed. An importance for a quick set-shifting of certain brain areas' involvement in the process of visual perception is discussed.