Volume 45, Nº 2 (2019)

To analyze the mechanisms of voluntary control of oculomotor behavior, including the inhibition processes, we studied the parameters and topography of the positive components of the event-related potential (ERP) to visual stimuli of various signal values in the saccadic “Go/NoGo” paradigm in 19 healthy right-handed subjects. The data we obtained suggest a different functional significance of the positive ERP components depending on the individual magnitude of the latent period (LP) of the saccadic response to the starting stimuli (Go). In the group of fast subjects (LP = 193 ± 10 ms), the Go-P100, Go-P200, and Go-P300 components may reflect the processes of decision-making, response initiation, and behavior monitoring, respectively; in slow subjects (LP = 277 ± 11 ms) they may reflect the processes of stimulus evaluation, decision-making, and response initiation. Regardless of the group of subjects, the NoGo-P100 component reflects the stage of evaluation of the inhibitory stimulus; the NoGo-P200 component reflects the stage of decision-making and saccade inhibition and the NoGo-P300 component reflects the stage of monitoring and analyzing the results of behavior.

The characteristics of neurocognitive processes during the perception of tonal modulation by using the technique of event-related potentials (ERPs) have been studied. The study involved 20 volunteers (six men, the average age of the participants was 19.7 ± 2.3 years). All the participants were right-handed; none of them had a professional musical education. The participants were asked to listen to a series of harmonic progressions with tonal modulation to the subdominant (near modulation, replacement of one tone with respect to the beginning scale), to the ascending minor sixth (distant modulation, replacement of four tones with respect to the beginning scale) and to the triton (distant modulation, replacement of six tones with respect to the beginning scale). The set of stimuli also included zero-step modulation to establish a baseline for the modulating stimuli. The data showed that N200 was decreased when listening to harmonic progressions regardless of the degree of modulation. It was found that the amplitude of P600 increased in response to an increase in the tonal distance between the beginning and ending tonalities, i.e., in response to an increase in the degree of modulation. This suggests that the amplitude of P600 corresponds to the degree of violation of tonal expectations, which, in turn, is associated with an increase in the complexity of the mental reorientation of the tonal scheme from one tonality to another tonality.

The study has assayed a new type of brain–computer interface technology based on the P300 wave (BCI–P300), in which an artificial hand with moving fingers was used as an executive device, and flashes of LEDs located on each finger were used as visual stimuli. The focus of the subject’s attention on particular LED flashes on the finger subjectively selected for flexion was detected by the P300 wave from the flash of the corresponding LED and transmitted to the electric drive of the corresponding finger. We have tested the hypothesis that the work of the subject in the BCI–P300 with control of finger drives of an artificial hand leads to an increase in corticospinal excitability, measured with transcranial magnetic stimulation (TMS). Neurophysiological trial involving 43 volunteers has shown that the corticospinal excitability actually increases when the fingers of the artificial hand are controlled through the BCI–P300 and does not change if the subjects simply observe independent movements of the fingers of the artificial hand, or work in the BCI–P300 with a panel of LEDs located separately from the hand. The confirmation of the hypothesis of increased corticospinal excitability during the active work of a subject with the control of fingers of the artificial hand in the BCI-P300 allows us to recommend this complex as a simulator of motor function in the recovery period after stroke or neurotraumas.

This work was aimed at studying the effects of physical exercise on brain electrical activity, cerebral blood flow, and cognitive function in athletes engaged in cyclic and acyclic sports. The study was performed on healthy young men at ages of 18 to 23 years. We used cognitive tests, electroencephalography, and rheoencephalography. Cerebral hemodynamics was shown to change after dynamic and static loading. The changes in blood flow after static loading were more marked than after dynamic loading. The results suggest that static loads cause a decrease in the activity of the EEG β- and θ-rhythms in the cognitive testing. It has been shown that cyclic loads have a positive effect on cognitive functions, while no such effects are observed after static loadings.

A new graphical method for determining the anaerobic threshold (AT), which has been experimentally tested in testing the maximal aerobic capacity in 46 cyclic sports athletes (mean age, 20.3 ± 3.6 years; body weight, 68.3 ± 10.4 kg). The gas exchange indices, the heart rate, the time of onset (from the beginning of the test) of AT by pulmonary gas exchange ratios, the non-metabolic CO₂ excess, the concentration of lactate in capillary blood, and the time of onset of AT determined by the proposed graphical method by the parameters of the pulsogram obtained during the test and 10-min recovery were determined. Two different protocols of load change—the incremental ramp test on a treadmill and the incremental step test on a bicycle ergometer—were used. Regardless of the protocol and the load type, statistical analysis revealed no significant differences between the results of AT measurements in the same athletes by the gas exchange and lactate dynamics indices, on the one hand, and by using the graphical method by the pulsogram parameters, on the other hand. In the test with a stepwise increase in load on a bicycle ergometer, as well as in the test with a smoothly increasing load on a running treadmill, the indices obtained at the AT that was determined by using the graphical method highly correlated with the indices obtained at the AT that was determined by analyzing the dynamics of pulmonary ventilation, non-metabolic CO₂ excess, and lactate concentration (p < 0.05). The proposed method does not require the use of sophisticated equipment and invasive procedures and can be widely used in sports and fitness practice.

We conducted immunological examination of men 40–69 years of age working in the aluminum industry with occupational bronchopulmonary conditions of various etiologies (chronic non-obstructive bronchitis (CNB) and chronic obstructive pulmonary disease (COPD)). Persistent polyclonal immunosuppression was observed in both CNB (95% of cases) and COPD (85%). We recorded differences in the production of antibodies (ABs) depending on the form of bronchopulmonary conditions. We detected an increase in the levels of ABs against the S100, β1-AdrR, GFAP, AdrM proteins in CNB. We found a decrease in ABs against LuS and β2-GP I combined with an increase in ABs against GFAP in COPD. These changes in the content of visceral ABs are more likely to reflect destructive and inflammatory processes in the corresponding tissue structures and, consequently, different mechanisms of disease. Using discriminant analysis, we determined the most sensitive indicators in the CNB diagnosis: ABs against membrane antigens of lung tissue (LuM), ABs against the S100 protein, which is a regulator of cellular functions, and ABs against cytoplasmic antigens of neutrophils (ANCA). The data can help to improve the quality of diagnosis of occupational bronchopulmonary conditions in aluminum industry workers and provide the most optimal treatment options.

The review presents the current understanding of interhemispheric asymmetry of the human brain activity, recorded by electrophysiological and hemodynamic methods using various sound features. Along with the anatomical differences which may exist between the auditory cortices of the left and right brain hemispheres, the authors consider how lateralization of auditory responses depends on the parameters of sound stimulation and what patterns of interhemispheric asymmetry can be found in auditory evoked potentials (AEP) elicited during spatial processing of sound stimuli.