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

Background: 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. Purpose: 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. Methods: 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. Results: 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. Conclusion: 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

Electrical activity of the cerebral cortex in men having high or low output alpha-frequencies while performing usual manual movements in response to sensory signals

A test group consisting of 104 healthy men from the ages of 19 to 21 was divided into two groups according to the magnitude of their individual α- frequency (ІАF) median―groups with high (n = 53, IA ≥ 10,04 Hz) and low (n = 51, IAF ≤ 10,03 Hz) levels of ІАF. Changes in power and coherence of the EEG oscillations during the usual manual movements as well as intergroup differences were evaluated. The higher level of the background tone of the cortex activation in men with a high IAF (individual alpha-frequency) was found as correlative with a significant selection of the relevant sensory information and a nonspecific input afferentation and its weakening under the performance of habitual manual movements. A functional state of the cortex is relatively lower in men with a low IAF and compensated by the tension of brain processes associated with a low level of the selective attention and the increase of the reticular influences and their significance during the finger movements. Men with a high IAF are characterized by the greater locality and asymmetry of processes of the cortical excitation under the dominant role of the left hemisphere. Activation changes are more diffuse in nature in subjects having a low frequency

Cortical Arousal Strategies in Left-Handers during the Aural Perception and Manual Playback of Mono- and Polyphonic Rhythmical Patterns

The actual purpose of this study is to establish the cortical arousal strategies (according to the power of the EEG (electroencephalogram) α-oscillations) during the aural perception as well as manual playback of mono- and polyphonic rhythmical patterns in men with left profile. The study involved 35 men from 19 to 21 years old with the left profile of the manual and aural asymmetries. EEG was recorded in the functional status of rest: during the aural perception and playback of mono- and polyphonic rhythmical patterns with the left and right hand fingers. The monophony in the rhythmical pattern sounding relative to monophonic patterns is followed by more expressed and widespread cortical processes of the EEG α-oscillation depression. Given patterns indicate a greater intensity of ascending nonspecific arousal strategies of data processing by men on conditions of the sound and harmonious complications of the pattern structure. The aural perception and playback of rhythmical patterns with both hands were accompanied by the increased significance of arousal processes in the right hemisphere. This may be due to the dominant role of the hemisphere during the formation of the innervation impacts on the left-hander’s neuro-motor apparatus. More differentiated changes in the cerebral cortex were installed during the left hand activation