Analysis of brain bioelectric activity during verbal-logical thinking of biology students
Authors: Tretiak T. O. , Sokorenko A. G. , Dregval I. V. , Severynovska O. V. 
Published: June 2017

75 female students of biology aged 18–22 were examined. The indicators of coherence of frequency components of electroencephalography in a quiet state and during solving tasks involving verbal-logical type of thinking, were assessed. The study included two stages: at the first stage, the individual psycho-physiological features of the students were investigated, then, the students investigated were divided into two groups, those with low and those with medium levels of performing tests. Performance of tasks involving verbal-logical thinking, compared with the background state, was characterized by polyrhythmic EEG activity with dominating δ-oscillations and prevailing δ-activity in the frontal area, which indicates their special role in regulation of complicated forms of cognitive activity. With development of ability of verbal-logical thinking, we established the increase in the spectral capacity in the frontal F3, F7, central С3, С4, parietal Р3, Р4 and temporal Т5 leads and increasing of synchronization in α-range in the left frontal zone, in areas near the Vernike zone and in the contour area F4–F8–T4–P4 of the right hemisphere. In the process of solving logical problems, the students with the low level of development of this cognitive ability demonstrated an increase of SC of β1-oscillation in Fp2, Р3, О2 leads, and the students with the medium level of development of logical thinking, on the contrary, demonstrated a reliable decrease in capacity of β1-oscillations in the central С4 and parietal Р4 leads. However, in the most productive students, a considerable number of significant functional connections and high values of coefficients of coherence between frontal F3–F4, F4–C4, central and parietal C3–P3, C4–P3, C4–P4 and occipital O1–O2 leads in the above mentioned EEG range were recorded. The spectral capacity of β2-components of EEG in students with different levels of development of logical thinking varied within background values and decreased in certain sections. The students with the medium level of manifestation of verbal-logical thinking demonstrated synchronization of SC of β2-range between frontal Fp1–Fp2, Fp2–F7, F3–F4 and other C3–C4, O1–T5, T3–T4 leads. While performing the tasks involving logical thinking, the students with low manifestation of this mental ability, did not demonstrate any considerable changes in indicators of SC of the θ-range. However, a reliable increase was established in the Fp1, Fp2, F7 and in О2 leads in the students tested in the group with the medium manifestation of cognitive ability. It should also be noted that with the development of verbal-logical way of thinking, the brain transfers in a special functioning mode with the low functional connection in the area of θ-oscillations, which indicates the preservation of the previously formed neural network. Therefore, in this work, we for the first-time distinguished special features and functional connections during performing verbal, rather than mathematical cognitive logical tasks: localization of loci of interaction at α-frequencies in frontal and central leads of the right hemisphere; β1 – in frontal leads of the left and central right hemisphere, β2 – in frontal and occipital left and in occipital areas of the right hemisphere. It was established that in low-frequency δ- and θ-ranges of EEG, both large cell ensembles, which embrace almost all right hemisphere, and separate sections in frontal, pariental, pariental-occipital locuses of the left hemisphere, are functionally integrated.