Vol 44, No 5 (2018)

The study included 22 healthy right-handed subjects (age 25.1 ± 3.9) and 9 patients with traumatic brain injury (TBI) (age 27.9 ± 7.3) without hemiparesis and local lesions in the sensorimotor cortex. The hemodynamical brain reactions were analyzed using functional magnetic resonance imaging (fMRI) during right- and left-hand movements. It was shown that reactive changes of responses have larger interindividual variability of the main topographic activation areas during left-hand movements as compared with right-hand movements in healthy subjects. In the TBI patients, the diffuse component of reactive changes was increased and involved a larger number of brain structures, both cortex areas and subcortical formations, including areas nonspecific for the motor analyzer. These changes were most clearly expressed in the dominant hemisphere (during movement of the right hand).

The purpose of this study was to investigate the relationship between the morphological parameters of the fovea, foveola, and foveolita of the human eye and the psychophysical and electrophysiological indices of the sensory and cognitive activities. We investigated the relationship between the sizes of these structures and the resolving power of the eye, as well as the influence of the size on the amplitudes and latent periods of various evoked potential components. It has been found that the foveola diameter affects the latent periods of the early waves of the visual evoked potentials (component P100) in the occipital areas. Our data confirm the effect of the foveola diameter on the parameters of cognitive processes during reading. In particular, it has been found that a larger fovea size provides the perception of a higher amount of printed characters.

Various types of dental disocclusion lead to disorders in the temporomandibular joint (TMJ) and subsequent abnormalities in the tone of the muscles of mastication. Prolonged dysfunction of the stomatognathic system leads to disorders in adaptation of the total musculoskeletal system, while the mechanism of this effect remains unclear. Plantographic characteristics of the feet were studied in nine children with stable deformities of the mandibular bones of a congenital or acquired genesis, and the distribution of plantar pressure was examined after reconstructive operations on the jaws and partial correction of occlusion. The plantographic characteristics were compared with those obtained in the same tests for 15 healthy children of the same age. Before surgery, the planthograms in tests with increasing load in the children with combined dentofacial and facial deformities differed in stiffness of all arches from the plantograms of the healthy children. Stiffness resulted in a significant increase in lateral support index, while the frontal and medial support indices were unchanged. After reconstructive surgery on the jaw(s) with restoration of the size, shape, and spatial position in the facial part of the skull, the support function of the external longitudinal arch of the foot recovered in the patients, but its recovery was accompanied by an increase in the rigidity of the transversal and internal longitudinal arches. Thus, the support function of the arches of the feet was disordered in children with stable deformity of the mandibular bones, and a change in biomechanical strategy was observed after reconstructive surgery.

Vascular resistance and blood pressure (BP) have known effects on blood viscosity. Therefore, the purpose of this study was to investigate the interrelation between the set of rheological characteristics and the parameters of microcirculation in patients with moderately increased blood pressure. We measured the hemorheological characteristics, including blood viscosity (BV) at high and low shear rates, plasma viscosity (PV), the viscosity of erythrocyte suspension, hematocrit (Hct), and erythrocyte aggregation and deformability. We also evaluated the efficacy of the transport function of blood. We determined the functional capillary density (FCD) using the method of microscopy and recorded the value of microvascular perfusion in patients with elevated blood pressure (mean blood pressure above 97 mmHg) and a group of subjects with normal blood pressure (control group, mean blood pressure of 87 mmHg) using laser Doppler imaging (LDI). We studied the changes in microrheological characteristics of red blood cells during their incubation in the presence of compounds with vasoactive properties: spermine (a donor of nitric oxide), ADP, and adenosine. Subjects with high blood pressure had a higher BP than the controls. This was due to an increase in PV, Hct, and erythrocyte aggregation with a decrease in their deformability. The ATP content of red blood cells was measured in patients with elevated blood pressure; it was found to be lower by 25% (p < 0.01) than in the control group. It was found that the content of ATP in erythrocytes was significantly negatively correlated with the values of blood pressure (systolic and diastolic blood pressures); the correlation was stronger in patients with a high blood pressure. These findings suggest that the characteristics of the hemorheological profile and the parameters of microcirculation in patients with moderately elevated blood pressure were significantly different from those in subjects with normal blood pressure. This indicates a reduction of the effectiveness of microvascular tissue perfusion.

Every year more than 100 million people travel through mountains. Many of these travelers are middle aged and even elderly in whom there is minimal cardiovascular research. In this study we evaluated sympathico-vagal tone before and after exposure to middle altitudes. 13 subjects, 7 women and 6 men, ages 45 to 72 were evaluated before and after exposure to middle altitudes. Evaluations consisted of cardiac loading during echocardiography as well as calculating the vegetative tone by using the Kerdo index. Vegetative tone was analyzed using the Fisher’s maximum-likelihood estimation, after which the integral under the line of best fit was obtained with limits defined as the shortest loading test in seconds when compared to baseline. Time to reach 85% maximally predicted cardiac rate increased for almost all subjects after exposure to middle altitudes. For the comparison of the vegetative control the integral of the fitting exponentials over time has been utilized. As demonstrated by an increase in the Kerdo index, 10 out of 13 of the subjects showed decrease followed by increase of the sympathetic responce as they acclimatized. Two of the three who did not demonstrate this shift has significant cardiovascular disorders which was discovered prior to exposure. We have demonstrated decrease followed by increase of the sympathetic response during proper acclimatization. We demonstrated this with the vegetative Kerdo index in 10 healthy subjects. Furthermore the majority of the subjects with underlying cardiac pathology failed to demonstrate this shift.

The serotonin transporter gene polymorphism is associated with plastic reconstructions of the brain structure and activity throughout life, which depend on the sex and age of the subjects. We studied the characteristics of the association between the serotonin transporter gene 5-HTTLPR polymorphism and the background EEG in healthy young (19–35 years, N = 89) and elderly (55–80, N = 60) men. The EEG power, calculated in individual frequency ranges from Δ- to γ-rhythms inclusively, was analyzed. Although the genotyping identified three alleles (SA, LG, and LA), we considered the division into groups with a high (LA/LA), intermediate (LA/LG, LA/SA), and low transcriptional activity (SA/SA, SA/LG), that were marked as L'/L', S '/L ', and S '/S ', respectively. Age-related differences were found in the association of the serotonin transporter gene 5-HTTLPR polymorphism with the power of the background EEG in θ and α₁ frequency ranges. Among the L'/L' and S '/L' genotype carriers, elderly men had lower indices of the θ and α₁ rhythm powers than young ones. Genetic differences in the power of these rhythms were detected in older men due to lower values in carriers of the S '/L' genotype as compared with S '/S ' and L'/L'. The results obtained contribute to the understanding of the mechanisms of heterogeneity of age-related reconstructions in the brain activity and related changes in mental and affective functions regulated by serotonergic system of the brain.

The use of oscillation parameters of the microvascular bed investigated using the laser technologies and laser Doppler flowmetry (LDF) is a promising tool in scientific and clinical studies in physiology and medicine and a new diagnostic language for the assessment of microcirculation. It provides a differential evaluation of microvascular control, including its innervation, the state of unmyelinated nerve fibers, and hemodynamics in microvessels, the diagnostics of model microvascular disorders, the investigation of information processes in microvascular bed, and differentiation of adaptive functional states.

This work continues the study of EEG-correlates of cognitive states with different contributions of sensory and mental attention. The design of the experiments was similar to that used for investigations of evoked EEG activity, but we analyzed spectral power parameters of quasi-stationary EEGs. Tests for sensory attention and for mental attention (productive and reproductive imaginary) were presented in blocks of 80 probes each. Each probe contained 2 signals: visually presented words designated an object of sensory or mental task in the probe, then a presentation of an image started a process of memorization, a presentation of a white screen started either a process of recollection, or a process of imaging. The evaluations of EEG spectral power in the states of sensory and mental attention and their comparison with the reference state of rest showed that the very scheme of a test with multiple inclusions of visual stimuli to trigger and to direct mental activities produced a specific functional state of rapid switching between the dominants of external and internal attention. The EEG correlates of mental states were rather different as compared with the EEG correlates obtained in extended uninterrupted states of mental attention.