Brain processes during the perception of sensory signals in men with high and low output α-frequencies

Human functional capabilities largely depend upon genetic qualities of person's nervous system. The registration of the spontaneous electroencephalogram (EEG) is among the physiological technigues allowing making a direct estimation of specific features of the nervous system, in particular, the human brain activity.

The study is devoted to the investigation of brain processes in men with high and low levels of individual α-frequency determined in a quiescent state during the perception of sensory signals.

A test group consisting of 104 right-hand healthy men from the ages of 19 to 21 was divided into two groups according to the magnitude of their individual α- frequency (IAF) median - groups with high (n = 53, IA ≥ 10,04 Hz) and low (n = 51, IAF≤10,03 Hz) levels of IAF. The power and coherence of the electrical activity of the cerebral cortex as well as inter group differences were evaluated in a quiescent state and during the perception of sensory signals by Subjects.

A localized power increase of the EEG α1-waves are registered in frontal areas, β1, β2- oscillations - in the anterior cortex, γ- activity - around the scalp and its decrease is present in the posterior temporal, parietal and occipital cortex leads, especially in the α- and β- frequency spectrum during the perception of sensory signals in men with a high IAF. The generalized depression of the θ-, α- and β- activity of the cortex is fixed in individuals with a low IAF while the expression of γ- waves is more local. The generalized increase of data in EEG coherence fluctuations throughout the frequency spectrum of the EEG in the cortex is set in all Subjects. The dextrocerebral preponderance is observable in posterior structures of the Subjects' right hemisphere. A localized decrease of the coherence concerning θ-, α1-, α3-, β- and γ- oscillations are traced in the frontal and anterior temporal areas of the left hemisphere.

We are of the opinion that the establishment of such common factors in the studied groups is an important step towards the release of the clear prognostic criteria for the functionality of men in the sensory area according to the congenital features of brain function.