Vol 110, No 12 (2024)

The perceptual-cognitive style (field-dependence or field-independence) determines the principal modality in space orientation and influences in posture control without distant stimulation. The aim of the work was to analyze stabilometric parameters in groups of field-dependent (FD) and field-independent (FI) subjects to describe vertical posture sway in response to a conspecific movement (human steps). The stabilograms were recorded for two groups of subjects (12 FD and 12 FI) in standard postures - heels together, toes apart, hands down along the body, eyes closed. The sounds of steps were created on the basis of a pre-recording in a room with reverberation. In free field three types of stimulation were used: steps approaching from behind and from the front; a control signal - a repeated step in place, given from behind. The changes of the center of pressure (CoP) position were analyzed for 64 s with a period of 8 s: before (1), during (3) and after (4) stimulation. The CoP parameters were the с and the length of CoP trajectory along the sagittal axis, and the area of the confidence ellipse. A slight destabilization of the posture during sound stimulation was shown in both groups of subjects. Differences between the groups were revealed: with the onset of the approaching step sounds the FD-subjects shifted the CoP away from the sounds (the “run” strategy), while the FI subjects shifted the CoP toward the sounds (the “hit” strategy). The results obtained substantiate the possibility to use the conspecific sound stimulation in rehabilitation procedures in the treatment of musculoskeletal diseases, taking into account the individual characteristics of perception in patients.

The research of mechanisms regulating aggressive behavior is one of the main problems of neurogenetics. Tame and highly aggressive strains of rats (Rattus norvegicus) obtained through long-term selection are a useful model for studying the mechanisms of genetically determined defensive behavior. The neurotransmitter serotonin (5-HT) controls many forms of behavior, including aggression. The activity of the brain's 5-HT system is regulated not only by its own elements, such as 5-HT1A and 5-HT7 receptors, but also by various modulators. Among their many, trace amines occupy a special place, the main receptor of which, TAAR1, is localized on 5-HT neurons pre- and postsynaptically. Among their diversity, trace amines occupy a special place, the main receptor of which, TAAR1, is localized on pre- and postsynaptic 5-HT neurons. NO is also a perspective modulator, the synthesis of which in the brain is activated predominantly by neuronal NO-synthase (NOS1). In the midbrain, hippocampus, hypothalamus and frontal cortex, NOS1 and TAAR1 expression levels was investigated in comparison with the level of 5-HT, its main metabolite (5-HIAA) and mRNA of 5-HT receptors (Htr1a, Htr7), as well as the expression and activity of TPH2 in tame and aggressive rats. In the midbrain and hypothalamus in the aggressive strain compared to tame rats was detected a decrease in the Htr1a mRNA level, while in the frontal cortex there was an increase in the expression level of the Htr7 gene. However, no interstrain differences in the TAAR1 protein level were detected in the investigated brain structures. Moreover, in highly aggressive rats, an increase in the Taar1 mRNA level was detected in the midbrain and hippocampus, while in the hypothalamus and frontal cortex it was not detected, regardless of the aggressiveness degree. The most significant changes in the 5-HT system of aggressive rats were found in the frontal cortex; an increase in the 5-HT metabolism index was revealed due to an increase in the 5-HIAA level. There was an inverse correlation between the 5-HT metabolism index and NOS1 expression. We hypothesized that the NOS1/NO system is an indicator of the 5-HT system functional activity under conditions of genetically determined aggression.