Fiziologiâ čeloveka

Speech is a continuous stream of sounds. To perceive speech, it is necessary to allocate discrete units with different frequency, volume and duration during its sounding. The purpose of this study was to identify the responses of the human cortex and midbrain to the transition from a consonant to a vowel sound in a syllable. The study analyzed and compared evoked potentials (EP) recorded using deep electrodes in 2 patients during intraoperative monitoring (IOM) with EP recorded in 29 healthy volunteers from the head surface. Groups of peaks following the beginning of the stimulus sound and the transition from consonant to vowel sound were detected on the EP registered in response to syllables and vowel sounds. Similar groups of short-latency peaks – S (from “start”) and C (from “change”), following the beginning of the stimulus sound and the transition from consonant to vowel sound, respectively, were distinguished on the patients’ EP. Their latencies had no significant differences (p > 0.05). Similarly, complexes of long-latent peaks N1_S-P2_S and N1_C-P2_C, similar to each other, were isolated on the EP of healthy volunteers. Their latencies also had no significant differences (p > 0.05). During the sounding of the stimulus, the cortex performs high-level (cognitive) sound processing, while the midbrain performs low-level (primary) processing, firstly providing rapid transmission of information to the cortex. With pathologies of the auditory structures of the thalamus and cortex, the ability to respond to changes in the characteristics of sound during its sounding, including speech, is likely to be impaired or lost.

The paper presents results of a study of changes in speed-strength factors of the musculoskeletal system of the human lower extremities and factors of accuracy in performing multi-joint movements after exposure to such models of the physiological effects of microgravity as 21-day head-down bed rest (HDBR) and 7-day dry immersion (DI) with electromyostimulation (EMS) as a preventive measure against muscle atony. Maximum jump height, as well as the accuracy and variability of the jump height to a predetermined height were studied. The results of the study showed that exposure to the microgravity models has a similar effect on the absolute speed-strength parameters of lower extremities muscles and leads to their decrease. At the same time, HDBR and DI have different effects on the accuracy of performing multi-joint movements to a predetermined height. Thus, after HDBR, the accuracy increased, and after DI it decreased or remained at the background level. The mentioned decrease in the accuracy after DI may be a consequence of the use of EMS during DI.

The widespread occurrence of disorders and diseases of the musculoskeletal system in children determines the need to study the functional state of the foot in the process of preventive and health-improving measures and in the hygienic assessment of factors of foot formation, including the influence of wearing children's shoes of different designs and weights. The aim of the study was to evaluate the functional state of the musculoskeletal system of the foot in children using standard functional physical activity. The study was conducted with the participation of 57 children aged 7–10 years. The functional load consisted in the maximum lifting the heels, standing on the toes, simultaneously 2 feet in the amount of 25 times at the pace of 1 cycle (stand on your toes and go down) in 2 s. The area of the plantar surface of the foot was determined using the podobarography method, the condition of the arch of the foot – using the plantography method. It was found that under the influence of the load, the area of the right foot did not significantly change – 82.33 ± 1.58 and 81.70 ± 1.74 cm² (p = 0.642), the area of the left foot decreased from 86.72 ± 1.50 to 81.93 ± 1.44 cm² (p = 0.000). For the right leading foot, this load turned out to be insignificant, which can be characterized as a manifestation of the “functional rigidity” of the foot in response to the load. For the left foot, the load caused a reaction of mobilization of the musculoskeletal system. The change in the area of the right foot before and after the load, depending on the condition of the arch of the foot, also turned out to be insignificant. For the left foot, in the normal state of the arch of both feet, the area after loading decreased from 80.31 ± 2.27 to 76.14 ± 2.55 cm² (p = 0.022), with flattening – from 92.78 ± 3.88 to 88.50 ± 3.55 cm² (p = 0.028), with flat feet – from 90.17 ± 5.35 to 84.25 ± 5.49 cm² (p = 0.050). The change in the area of the plantar surface of the foot in response to physical exertion can be used to study the functional state of the musculoskeletal system of the foot during preventive medical examinations, evaluation of the effectiveness of preventive and corrective technologies, as well as in the hygienic evaluation of the design of children's shoes.

A comparative determination of immunological parameters, natural antibodies (e-Abs) to the regulators of the main systems of biochemical homeostasis was carried out: β-endorphin, serotonin, dopamine, histamine, orphanin, angiotensin, GABA, glutamate, bradykinin, vasopressin, thrombin, α2-macroglobulin in persons with phantom pain syndrome (PPS) resulting from amputation after injury. In accordance with the established diagnosis, a group of 14 people was examined, for whom features of the distribution of immunological parameters were identified. For each examined patient, an individual immunoprofile of specific e-Abs was determined. A significant increase in the level of antibodies to serotonin, histamine and angiotensin was established for all study participants, reflecting the degree of manifestation of FBS, which does not depend on the self-esteem of the person being examined. Determining the role of regulators of biochemical homeostasis in the development of phantom pain showed that with high, moderate and weak severity of FBS, the biogenic amine and angiotensinergic systems are activated. A decrease in FBS intensity normalizes deviations in all immunological parameters. The level of e-Abs for the pain (β-endorphin) and analgesic (orphanin) systems are significant only at low FBS. Monitoring the individual profile of e-Abs to endogenous regulators allows us to obtain an objective picture of the pain status of the patient’s body. The severity of pain, assessed on various scales, may have no connection with the degree of imbalance of these systems, with neurophysiological and other characteristics of the manifestation of pain.

To date, there is evidence that support stimulation of the feet in neurological practice is a promising method for motor rehabilitation. The implementation of support stimulation is possible in various ways, but according to the results of modern research, mechanical stimulation of the feet demonstrates the greatest effectiveness. At the same time, the area, localization and intensity of mechanical support stimulation determine the activation features of the cutaneous mechanoreceptors of the soles, affecting evoked motor responses. From this perspective, the question of which type of mechanical support stimulation is the most practical and prospective remains relevant. In this review, we consider the currently existing approaches to mechanical support stimulation, as well as the results of their application in medical practice in order to improve motor abilities in patients.

The imbalance between energy intake and total energy expenditure is the cause of a negative energy balance, and in combination with prolonged intense exercise, it can lead to the development of low energy availability (LEA). The concept of LEA is associated with a number of endocrine, cardiovascular, inflammatory, gastrointestinal, and mental characteristics, which have been combined under the term Relative Energy Deficiency in Sport (RED-S). The analysis of the world literature has shown a high prevalence of LEA and RED-S against the background of insufficient awareness of coaches and athletes about energy deficiency and its negative health consequences, which actualizes the importance of this problem. That is why the issues of early diagnosis, adequate treatment, and prevention of RED-S, taking into account the specifics of the sport, gender, and age, are of great practical importance.