Spectral Characteristics of the EEG Theta-Band and Efficiency of Cognitive Test “N-Back” Performing

Abstract

Effectiveness of cognitive test “n-back” performing was assessed in 32 subjects, right-handed men, 18—21 years old. EGG was recorded monopolarly in “10—20” system during initial state, in the period after the first learning stage and during the second learning stage while the subjects performed the test on their own. Two groups of subjects were marked, basing on differences between efficiency of their cognitive activity. Spectral analysis revealed none differences in theta-band spectral power between subjects of the two groups at the initial state. Successful subjects demonstrated increase of the theta-band spectral power in occipital, parietal, central and left frontal zones of cortex in the period after the first learning stage comparing to unsuccessful subjects. On the contrary, unsuccessful subjects demonstrated significant increase of the theta-band spectral power in the second learning stage during the test self-performing comparing to the initial state and the period after the first learning stage. Increase of spectral power of the theta-band can be considered as a regression stage of systemogenesis, accompanied by increase of the representation of low-differentiated systems in new behavior realization and causing high efficiency of cognitive activity.