Том 49, № 5 (2023)

The development and improvement of closed-loop methods for non-invasive brain stimulation is an actual and rapidly developing area of neuroscience. An innovative version of this approach, in which a person is presented with audiovisual therapeutic stimulation, automatically modulated by the rhythmic components of his electroencephalogram (EEG), is EEG-guided adaptive neurostimulation. The present study aims to experimentally test the assumption that the effectiveness of EEG-guided adaptive neurostimulation can be increased by optimizing the parameters of preliminary resonance scanning, which consists of LED photostimulation with stepwise increasing frequency in the range of θ-, α-, and β EEG-rhythms. In order to test this assumption, we compared the effects of two types of resonance scanning, which differ in the step length of the gradually increasing frequency of LED photostimulation. The experiments involved two equal groups of university students in a state of exam stress. Before EEG-guided adaptive stimulation, one of the groups underwent resonance scanning with a short (3 s), and the other with a long (6 s) step of a gradual increase in the frequency of photostimulation. Changes in the EEG and psychophysiological parameters were analyzed under the influence of combined (resonance scanning plus EEG-guided adaptive neurostimulation) interventions relative to the initial level. It was found that only with a short (3 s) step of increasing the frequency of photostimulation, significant increases in the power of EEG-rhythms are observed, accompanied by significant changes in subjective indicators – a decrease in the number of errors in the word recognition test, a decrease in the level of emotional maladaptation, and an increase in well-being scores. The revealed positive effects are already observed after single therapeutic procedures due to the optimal conditions for the involvement of the resonant and integration mechanisms of the brain and the mechanisms of neuroplasticity in the processes of normalization of body functions. The developed combined approach to neurostimulation after additional experimental studies can be used in a wide range of rehabilitation procedures.

In order to clarify the neurophysiological mechanisms of psychological deterioration after coronavirus infection in 54 young female patients with depression who had previously undergone COVID-19, the relationships of neurophysiological (EEG) and psychological (according to the SCL-90-R inventory) parameters have been analyzed. The index values of some scales of the SCL-90-R questionnaire, reflecting the severity of symptoms associated with a weakening of control of activity and with increased excitability in the emotional sphere, significant positive correlations were found with the spectral power values of the EEG frequency sub-bands, indicating a reduced functional state of the frontal cortex, as well as increased activation of stem and limbic structures of the brain. The structure of correlations between psychological parameters and EEG spectral parameters in depressive patients who underwent COVID-19 indicates that psychological discomfort that persists after the disease (long covid) is associated with a decrease in the functional state of the frontal areas of the cortex, as well as with the “disinhibition” of the stem and limbic structures of the brain, possibly due to the weakening of the descending inhibitory influences from the frontal cortex.

The effect of the masker on the localization of the moving signal was investigated in the free field conditions. Bandpass noise bursts (5–18 kHz) were used to create a signal and a masker. The signal and the mask were uncorrelated stimuli and were created from two independent noise bursts. The stationary masker was always on the right at an angle of 15 degrees. The moving signals traveled to or from the masker along two paths located at two places (–86°…–52° and –52°…–18°). The signal and the masker of 1 s duration each were presented either simultaneously or with a delay of the signal onset relative to the masker onset. The delay varied from 1 to 40 ms and 1200 ms. The subjects localized the start and end points of the trajectory of the moving sounds. Localization of the start and end points of the signal in masking condition was compared with localization of the moving source alone. Results showed that the masker affected the start and end points of the signal trajectory. The shift depended on the direction of movement. The starting points were always shifted in the direction of motion of the signal. The end points were shifted in the opposite the direction.

The aim of the work was to study the influence of balance training on the regulation of the balance of the monosupport posture of young physically active girls (n = 26, 17–21 years old). For 10 weeks (3 times a week), 13 girls trained according to the program of training the ability to maintain balance in postures on unstable (balance-simulators) and supports limited in area, and 13 girls made up the “Control”. The stability of the monosupport posture was analyzed by the speed and area of fluctuations in the common center of pressure (COP) in static (in a stance on a fixed stabiloplatform with open (OE) and closed (CE) eyes) and semi-dynamic conditions (in a stance at low h = 12 cm with OE and CE and high h = 30 cm see-saw with CE). Strength abilities of the thigh muscles and extensibility of the calf muscles were recorded using functional tests. Proprioceptive sensitivity was defined as an reproduction error of the tilt of the straight body in the ankle joint. Compared with the “Control” group, the trained girls showed an significant increase in the strength endurance of the hip extensors and flexors, the accuracy of reproduction of the inclination of the vertical body, as well as the stability of the monosupport posture in static and semi-dynamic positions only with closed eyes. Effect size of the balance-training was greatest in improving the postural stability on the see-saw with CE. The suggested mechanisms for improving postural stability are an increase in the strength abilities of the leg muscles and the specific proprioceptive sensitivity of the postural system.

The aim of the present study was to analyse rest energy expenditure (REE) and energy expenditure (EE) during submaximal exercise according to performance of athletes. A retrospective analysis of data from 2014 to 2020 among cross-country skiers in the preparatory phase was performed. Depending on the potential performance athletes (n = 136) were divided into two groups: I – test completed to the anaerobic threshold (AnT), II – test completed until exhaustion. The present study included the data only before AnT for a correct comparison of the results. REE was 2058.5 ± 220.5 kcal/day in I group and 2023.1 ± 216.4 kcal/day in II group (p = 0.481). In REE structure, the contribution of fats and carbohydrates (CHOs) was 69 and 31% in I group, 48 (p = 0.021) and 52% (p < 0.000) in II group. Correlations between VO_2rest and REE, as well as the rate of fats and CHOs oxidation at rest were revealed. In I and II groups the VO_2AnT (p < 0.000) and relative values of VO_2max (p < 0.05) were significantly different. EE before AnT was 135.9 ± 31.2 and 134.0 ± 23.4 kcal (p = 0.399) for I and II groups. The present study showed that the balance 1 : 1 of fats and CHOs in the REE structure is a more informative performance marker than quantitative assessment of EE. VO_2AnT reduced by 20% relative to VO_2max may indicate the functional economization and the body’s ability to perform exercise during long time, including in the anaerobic exercise. Endurance athletes demonstrated economy of CHOs against actively using of fats during submaximal exercise. Complex estimated of performance indicators and EE (including contribution fats and CHOs) should be taken into account when studying the performance of athletes.

Manifestations of the illusion of a three-dimensional structure appearing when rotating a flat projection of a three-dimensional object (structure from motion (SfM)) were studied in three groups of children aged 7 to 17 years: 1) 40 children of the control group with orthotropy, the normal state of visual functions (including binocular and stereovision) and fundus; 2) 33 children with non-paralytic strabismus and normal fundus condition; 3) 50 children with non-paralytic strabismus on the background of congenital partial atrophy of the optic nerve (PAON). As a test image, we used the figure of a hexagon with diagonals passing through its center, presented in binocular and monocular observation conditions in the form of a still image, and when it rotates at a speed of 5, 10, 15, 20, 30, 40 rpm. It was shown that the perception of a three-dimensional structure in the form of a cube is possible with a stationary presentation of a test image in 2–3% of children of both the control group and groups of children with strabismus in binocular and monocular observation conditions. When rotating the test image in both binocular and monocular observation conditions, the number of children who perceived the cube in all groups increased with increasing image rotation speed, reached maximum values at 15–30 rpm and significantly decreased at 40 rpm. In the control group, during the transition from binocular observation conditions to monocular, the number of children perceiving the image as a cube significantly increases at rotational speeds of 5 rpm (p = 0.023), 10 rpm (p = 0.005), 20 rpm (p = 0.002) and 30 rpm (p = 0.001). In groups of children with strabismus (both on the background of normal fundus and on the background of PAON), binocular and monocular indicators were statistically comparable (р > 0.05). Comparison of indicators in different groups demonstrated a greater number of children perceiving a three-dimensional figure in the control group than in both groups of children with strabismus at certain speeds of rotation of the test image (from 10 to 20 rpm). In groups of children with strabismus on the background of normal fundus and children with strabismus on the background of PAON, binocular and monocular indicators are statistically comparable for all image rotation speeds. There was no significant dependence of the nature of the perception of the test image on age in all the studied groups of children. Thus, along with the general patterns of SfM manifestations in children of the studied groups, differences were revealed due to the nature of the interaction of monocular and binocular mechanisms of spatial perception in normal and ophthalmopathology. Thus, the SfM study can be used to evaluate the effects of depth and force relations of the monocular and binocular mechanisms of spatial perception in normal and ophthalmopathology.