Vol 43, No 4 (2017)

The precedence effect refers to a group of auditory phenomena related to the ability to locate sound sources in reverberant environments. In the present study, this phenomenon was investigated using two moving signals. The first signal was direct (lead) and the other was delayed (lag). The motion of the sound source was created by successive switching of ten loudspeakers. The continuity of the motion was created by simultaneously attenuating the stimulus in the previous loudspeaker and enhancing it in the next one. The length of the path of the lead and lag was 34°. The lead moved from 34° to 0° (to the right) and the lag moved –52° to –86° (to the left). The duration of the lead and the lag was 1 s. Lead–lag delays ranged from 1 to 40 ms. Subjects had to indicate the location of the lag. The results indicate that the lead signal dominated in the sound localization at short delay durations (up to 18 ms). In spite of the instructions, all the subjects pointed at the lead, which suggests that they perceived the lag in this location. Two distinct sounds were perceived at the longest delays. The mean echo threshold and its standard deviation in eight subjects was 9.6 ± 4.5 ms.

The model of fixed set (for Uznadze’s paradigm) was used to estimate the functional activity of the cortico-thalamic system of selective attention and cortico-hyppocampal system of emotional and volitional activity in second-year medical students with learning difficulties (n = 20). The control group (n = 30) consisted of successfully studying students of the same year. We observed a significant reduction of induced reactions of neocortical EEG α oscillations in response to the facial stimuli or conditioning Go/NoGo signals in underperforming students. This indicates a decrease in the functional activity of the corticothalamic system of selective attention, i.e., weakening of the top–down cognitive control. This disorder is the psychophysiological basis of cognitive difficulties in the learning process. The amplitude of θ-range cortical potentials in underperforming students is significantly higher than that in the control group, i.e., the level of functional activity of the cortico-hippocampal system is higher, which indicates a higher level of stress. These findings make it possible to conclude that psychophysiological laboratory studies should be used as a supporting tool for high school teachers and psychologists during their work with students with learning difficulties.

The purpose of this study was to evaluate the parameters of somatosensory evoked potentials (SSEPs) in healthy children of different age groups (n = 94). The amplitudes of the main cortical peaks and the central sensory conduction time (CSCT) from n. medianus and n. tibialis in children aged under 12 months, 1–12 years, and 12–17 years were estimated and compared. No significant cortical peaks were recorded from the tibial nerve in five children younger than 1 year (5 out of 23, 22%). Significant differences in CSCT were observed between the children younger than 1 year and two other groups. The amplitudes did not significantly differ between the groups. Thus, SSEPs may be used for the evaluation of somatosensory pathways in children aged one month to 17 years. CSCT differs significantly between children younger than 1 year and other age groups. Age-related reduction in CSCT and elevation of the cortical peak amplitudes may reflect the myelination of somatosensory pathways and the improvement in nervous system integration.

On the basis of the concept of the typological variability of human physiological individuality, we have determined the systemic correlation between the indicators of cognitive activity and the parameters and development of emotional intelligence (EI) and the formation of typical behavior strategies in older preschool children of three functional types (FT-1, FT-2, and FT-3), including subjects with low (LHPA), medium (MHPA), and high (HHPA) levels of habitual physical activity. We revealed the EI features typical of each functional group of children and observed a strong negative correlation between the indicator of HPA and the total EI score. The typical manifestation of EI is closely related to other psychological parameters of cognitive and emotional–volitional activity (logical and imaginative thinking, state anxiety, and attention), which allowed us to establish the constitutional features of the behavior strategy on the basis of the integrated assessment of all the obtained data. In different conflict situations, children with HHPA (FT-3) made decisions more rapidly and by themselves; their decisions were active and aimed at achieving a specific goal on the basis of domination (individual problem solving). In contrast, children with LHPA (FT-1) solved the problems on the basis of the emotional state of other people and preferred to explain the situation to their parents or educators and ask for help (cooperative problem solving). Up to 10% of children with LHPA preferred not to solve the problem.

The ability of athletes with different training specializations to recover vertical posture after an external pushing impact was studied. Athletes engaged in cyclic exercise sports (jogging, n = 7) and complex coordinate sports (wrestling, n = 10) and nonathletes (control, n = 10) were the subjects of this study. The recovery of vertical position after a small external pushing impact on the arms extended forward was assessed using stabilography. We determined the maximum amplitude (Amp-m) of deviation from the general center of pressure, the reaction time (RT) and the velocity of reaction (V-r), as well as the variance and mean velocity of vertical posture oscillations before and after an impact. It was found that, although no differences were observed in the vertical posture stability before pushing, the Amp-m was lower in the wrestlers than in the control group (by 17.5%, p = 0.018 under the eye-open conditions; by 27.3%, p = 0.002 under the eye-closed conditions). The deprivation of visual information about the pushing moment increases the Amp-m and V-r and had no effect on the RT in all groups. Under the eye-closed conditions, an increase in Amp-m as a result of pushing was significantly lower in the wrestlers (p = 0.033) than in the control group. Under the eye-closed conditions, the accuracy of the recovery of the initial vertical position after pushing was higher in the wrestlers than in the control group (p = 0.027). The indicators of postural stability, displacement of the center of pressure, and vertical posture sway and recovery after pushing did not differ between the runners and other groups. Therefore, compared to cyclic exercises, training in complex coordinating sports more effectively improves the ability to maintain vertical posture in response to its perturbation.

Aerobic exercise training is associated with adaptive changes in skeletal muscles and their vascular bed; such changes in individual muscles may vary depending on their characteristics and recruitment. This study was aimed at comparing the effects of eight-week treadmill training on the locomotor and respiratory muscles in rats. The training course increased the aerobic performance in rats, which was evidenced by an increase in maximum O₂ consumption and a decrease in the blood lactate concentration in ramp test. The succinate dehydrogenase activity was increased in the red portion of the gastrocnemius muscle, but not in the diaphragm of trained rats. Arterial segments were isolated from feed arteries and studied by wire myography. The relaxation in response to acetylcholine in gastrocnemius arteries in trained animals was higher as compared with controls (due to higher NO production), while contractile responses to noradrenaline (in the presence of propranolol) were not changed. On the contrary, the endothelial function of diaphragm arteries was not affected by training, but contractile responses to activation of α-adrenoceptors were markedly increased. Thus, aerobic training may increase the blood supply rate to both locomotor and respiratory muscles, but the underlying regulatory mechanisms are different. The results obtained allow us to reveal the physiological mechanisms that determine the physical performance of the body under conditions of compromised functioning of the respiratory system.

The cardiohemodynamic and blood microcirculation parameters at rest and under local cold exposure in young male subjects have been estimated. It has been found that the subjects with the initially low velocity of erythrocytes (blood flow) in their nail bed capillaries have higher blood pressure, stroke volume, cardiac output, and cardiac index, which proves that these subjects have the hyperkinetic type of blood flow with the pronounced hypertensive reaction. At the same time, the shift of heart rate variability values under the cold exposure indicates that the activation of the sympathetic autonomic nervous system is more statistically significant than that in those subjects who originally had a higher velocity of erythrocytes. In the subjects of this group, no changes were observed in either heart rate autonomic regulation or index of tension under the local cold exposure, which proved that these subjects had the enhanced functional reserves of the cardiovascular system and autonomic regulation. They also had a fairly pronounced reactivity of the parameters of systemic hemodynamics, which manifested itself in changes in their blood filling parameters against the background of decrease in total peripheral vascular resistance and coefficient of integral tonicity.

The review focuses on the key sodium transporters involved in maintaining water–salt balance in the kidney. The topography of sodium transporters is discussed. Specifics of the hormone-dependent regulation, including phosphorylation, traffic, and expression, are considered for particular transporters. Special attention is paid to direct intracellular regulators of the transporter function. The role that dopamine plays as a natriuretic factor in modulating the function of various transporters is described.

Electroencephalographic brain dynamics during the menstrual, follicular, preovulatory, ovulatory, luteal and premenstrual phases of the female ovarian-menstrual cycle were analyzed. All subjects were divided into 3 groups according to individual alpha peak frequency and reaction to rhythmical photostimulation. Data obtained confirm the necessity to carry out experimental and clinical psychophysiological studies of women in the phases of the ovarian-menstrual cycle.