[Electrophysiological and morphohistochemical study of adrenalectomy on the hippocampal neurons].

Chronic insufficiency of adrenal hormones is a pathology leading to brain dysfunction. In electrophysiological studies, by extracellular recording of spike activity of single hippocampal neurons (HN) caused by high-frequency stimulation of the entorhinal cortex (EC) in rats with unilateral removal of adrenal (adrenalectomy - AE), we analyzed mechanisms of adaptation of neural networks to chronic hormonal deprivation. The balance of excitatory and inhibitory responses, recorded in HN of intact rats was submitted to characteristic changes in dynamics of development of neurodegeneration: the dominating in norm inhibitory responses were decreased at all AE terms (from 42 % to 25 % by the 18th week). On the contrary, the minimal in norm percent of excitatory responses sharply increased (from 17 % to 60 %) at the 25-27th day after AE, which indicates a possible increase of cholinergic neurotransmission. There was recorded a high level of the mean frequency of peristimulus spiking from the 25-27th day to the 18th week after AE, which indicates the high glutamate level or pronounced activation of NMDA receptors. On the whole, the ratio of excitatory/inhibitory HN responses indicates discoordinated activity of neuronal chains of EC-HN under conditions of AE. Histochemical analysis revealed an increased sensitivity to AE in neurons of the CA1 fields. After disturbance of neuronal structure by the 5th day, 25-27 days after AE, there was observed proliferation cell elements in the CA1 field; as a result, by the 10th week, there is observed the complete filling of "devastated" areas of hippocampus and a sharp rise of phosphatase activity in nuclei of dentate gyrus. 18 weeks after AE, the majority of the CA1 field neurons are submitted to chromatolysis, and the phosphatase activity falls. The presented data make certain contribution to understanding of mechanisms of control of cognitive brain functions and plasticity in interconnection with the hormonal factor.

[Gender differences of dynamic changes of anterior cortical activity under negative emotional strain].

Dynamic changes of anterior cortical areas activity under negative emotional strain at male and female teenage examinees were investigated. Dependence of anterior cortical activity changes on gender and initial conflictness level of examinees is determined, which is also confirmed by detected shifts in phychoemotional sphere.

[Autonomic cardiac rhythm regulation in adolescents during simulation of conflict-inducing medium].

Autonomic balance shifts were studied from the parameters of cardiac rhythm variability in subjects of both sexes with a varying conflict potential under the influence of a conflict-inducing factor. There was autonomic balance displacement towards a reduced sympathotonus in conflict subjects irrespective of gender and in non-conflict girls during simulation of a conflict-inducing medium, which suggests their favorable response to presented loads. The sympathetic part of the autonomic nervous system was found to play an increased role in the regulation of cardiac performance in examined non-conflict boys during simulation of a conflict-inducing medium, suggesting the development of psychogenic emotional tension by the negative psychosomatic type.

[Gender differences of the influence of an "aggressive" computer game on the variability of the heart rhythm].

The influence of virtual aggressogenic environment on psychoemotional sphere of male and female teenagers with different levels of personal aggression was studied by characteristics of the heart rate. The exposure to the aggressogenic factors produced a change of the centralized control for the autonomic control in female and male teenagers with the high level of aggression and females with the low level of aggression. Male teenagers with the low level of aggression displayed the prevalence of the centralized control. Thus, the influence of exposure of teenagers to the virtual aggressogenic environment was shown to be ambiguous depending on the level of the level of personal aggression and gender.

[Stress index as an indicator of autonomic regulation while working on a computer].

Cardiac rhythm variability was studied in examinees of both sexes with varying aggressiveness during simulation of the virtual aggressogenic environment. Central regulation showed a shift towards autonomic one in highly aggressive examinees of both sexes and in lowly aggressive girls and there was a preponderance of central regulation in lowly aggressive boys under the influence of an aggressogenic factor. There was an association of the intensity of responses to an aggressogenic factor with gender.

[Changes in the P300 amplitude under the influence of "aggressive" computer game in adolescents with various levels of initial aggression and conflicting behavior].

Dynamic changes in the amplitude of component P300 of the evoked potentials in different cortical areas were studied as an index of activity of cortical structures responsible for actualization of a computer game with aggressive content with regard for the level of initial aggression and conflict in behavior of adolescent subjects. Dynamic changes in anxiety and aggression evoked by playing an "aggressive" computer game were shown to be dependent on the initial level of aggression and conflict. An increase in P300 in the frontal and orbitofrontal areas of both hemispheres was observed in adolescents with initially high level of aggression and conflict. In adolescents with initially low aggression and conflict, P300 decreased bilaterally in the frontal areas and did not change significantly in the orbitofrontal areas. These findings testify to the bilateral frontal top-down control over negative emotions.

[Impact of aggressive assigment performance on the autonomic nervous systems in adolescents].

Impact of aggressive assignment performance on cardiac rhythm was studied in adolescents, by taking into account permanent aggressiveness and autonomic tendency in the examinees. The adolescents with high baseline aggressiveness were found to have a lower Kerdo autonomic index while the latter was not observed in those with low baseline aggressiveness. Aggressive computer games have been ascertained to have no negative impact and to have a beneficial effect on the adolescents' psychoemotional sphere.

[Effects of spatial-imagery task performance on the heart rate variability].

Effects of the efficiency of spatial task performance on the autonomic heart control were studied. Dynamic changes in autonomic balance diagnosed on the heart rate variability during maze-model task performance (the type of spatial-imagery activity) showed that the type of heart rate regulation depended on the performance efficiency. The results suggest that in subjects with low performance efficiency, problems in performance are associated with negative emotions that produce the emotional psychogenic stress. In subjects with high efficiency, the autonomic contour of the heart rate regulation prevailed. This was presumable associated with the adequacy of the maze-model task.

[The study of interhemispheric asymmetry in spatial-perceptive problem solving]. / Issledovanie mezhpolusharnoi asimmetrii mozga pri reshenii zadachi prostranstvenno-obraznogo profilia.

Features of brain interhemispheric asymmetry during solving the spatial figurative task (maze model) were studied in men and women with different intelligence quotients (IQ). It was shown that during task solving the rate of information processing was higher in the right brain hemisphere, and amplitude characteristics of the event-related potentials were higher in the left hemisphere. No gender and IQ differences in the character of interhemispheric interaction were found during the realization of the maze-model task. The results testify that the character of hemispheric interaction depends om the task rype rather than gender and intelligence level.