[Comparative evaluation of the EEG in adolescents with different risk of the Internet addiction living in the Northern and Southern regions]. / Sravnitel'naya otsenka EEG-kharakteristik u podrostkov s razlichnym riskom internet-zavisimosti, prozhivayushchikh v severnom i yuzhnom regionakh.

OBJECTIVE: Performing comparison of EEG in adolescents living in the Northern and Southern regions and having different risk of Internet-addiction (IA). MATERIAL AND METHODS: School adolescents of 16-17 years old, permanently living in the Northern (n=55) and Southern (n=55) regions of the Russian Federation were examined. According to Chen's scale (CIAS) the adolescents living in both regions were divided into 3 groups: group I - with minimal risk of IA; group II - with IA inclination; group III - with formed IA. EEG spectral power (µV2) was evaluated in every spectral band. RESULTS: In the samples of Northern/Southern regions 25.5/38.2% individuals of group I; 63.6/47.3% - of group II; 10.9/14.5% - of group III were revealed. There was a tendency to increase EEG spectral power with increasing IA risk. In both regions the highest θ-band spectral power in the central zones and the left temporal zone were revealed among the representatives of group II (p<0.05-0.01). There were revealed the highest α-band spectral power in the left hemisphere among the representatives of group III (p<0.05), among the representatives of the Southern region the highest ß1-band spectral power in the central zones and in the left frontal and left occipital zones was revealed (p<0.05-0.01). Among the representatives of group II and III of the Northern region there were higher EEG spectral power values compare to those of the Southern region's representatives, predominantly in the left and frontal zones (p<0.05-0.01). CONCLUSION: Thus, variants of adaptive reactions of the brain activity were revealed, which reflect specificity of the IA formation and heterochrony of the EEG pattern formation in adolescents of the Northern region.

[EEG spectral characteristics during heart rate variability biofeedback in healthy people]. / Izmenenie spektral'nykh kharakteristik élektroéntsefalogrammy v protsesse bioupravleniia parametrami variabel'nosti serdechnogo ritma u zdorovykh.

AIM: To evaluate changes in electroencephalogram (EEG) spectral characteristics during a single session of heart rate variability biofeedback (HRV BF). MATERIAL AND METHODS: One hundred and fifty adolescents, aged 16-17 years, were studied. Adolescents of the BF-group (n=110) conducted HRV BF session to enhance vagal influences on the heart rhythm. Adolescents of the control group (n=40) remained in relaxed resting state. EEG was recorded with eyes closed before and after BF training. EEG absolute spectral power values of parts without artifacts in each frequency band were determined. RESULTS AND CONCLUSION: The ability of the volunteer to change the heart rhythm activity determines the extent of its impact on the functions of central autonomic structures. This method of BF training helps to improve the cortical stability: an increase in alpha- and decrease in theta EEG-activity. The synchronization process of brain activity in the dynamics of BF training is most clearly manifested in the right brain hemisphere, with the frequent involvement of prefrontal brain areas.

[Individual Types Reactivity of EEG Oscillations in Effective Heart Rhythm Biofeedback Parameters in Adolescents and Young People in the North].

A single session of heart rate variability (HRV) biofeedback in apparently healthy young people and adolescents aged 14-17 years in order to increase vagal effects on heart rhythm and also electroencephalograms were carried out. Different variants of EEG spectral power during the successful HRV biofeedback session were identified. In the case of I variant of EEG activity the increase of power spectrum of alpha-, betal-, theta-components takes place in all parts of the brain. In the case of II variant of EEG activity the reduction of power spectrum of alpha-, betal-, theta-activity in all parts of the brain was observed. I and II variants of EEG activity cause more intensive regime of cortical-subcortical interactions. During the III variant of EEG activity the successful biofeedback is accompanied by increase of alpha activity in the central, front and anteriofrontal brain parts and so indicates the formation of thalamocortical relations of neural network in order to optimize the vegetal regulation of heart function. There was an increase in alpha- and beta1-activity in the parietal, central, frontal and temporal brain parts during the IV variant of EEG activity and so that it provides the relief of neural networks communication for information processing. As a result of V variance of EEG activity there was the increase of power spectrum of theta activity in the central and frontal parts of both cerebral hemispheres, so it was associated with the cortical-hippocampal interactions to achieve a successful biofeedback.

[Comparison of electroencephalogram changes at cardiovascular training in adolescents of subpolar and polar northern territories].

The features of the electroencephalogram (EEG) at the heart rate variability single biofeedback session in adolescents aged 15-17 years living in the subpolar and polar northern regions were determined. In adolescents of the subpolar region identified shaped age EEG pattern. We have established higher diencephalic and subcortical brain structures activity manifested in the elevated theta-activity levels and the diffuse photic driving reactions in adolescents of the polar region than in adolescents of subpolar region. In the dynamics of the biofeedback sessions in both regions there were identified groups of persons with both increased alpha-activity spectral power and decreased of it. After biofeedback sessions in adolescents of polar region more prolonged increase of alpha-activity, more pronounced reduction of theta-activity and the photic driving reactions were revealed. Changes in EEG patterns are most characteristic of the right brain hemisphere involving the frontal brain areas.

[Synchronization in human heart rate dynamics and Pc5 geomagnetic pulsations at different latitudes].

Eight experiments were conducted in synchronized monitoring of cardiac indices in six healthy women at rest simultaneously in three geographic locations--Sofia, Moscow and Arkhangelsk. Comparing spectra of the dynamic time series of the pulse and variations in the horizontal component of the geomagnetic field vector in the frequency range of Pc5 geomagnetic pulsations showed that the main oscillation periods represented in physiological and geophysical time series at each time moment largely coincide. This effect was observed roughly to an equal extent for volunteers who underwent the measurements in all three geographic locations.

[Autonomic nervous status and bioelectric brain activity in adolescents-inhabitants of the Polar north].

BACKGROUND: Northern European areas are differing in degree of extreme climatic conditions in the Polar and Subpolar latitudes. Formation of the nervous system in adolescents most of all is affected by these adverse climatic factors. OBJECTIVE: The aim was to study of the autonomic regulation of cardiac activity and brain bioelectric activity in adolescents-inhabitants of the North depending on these autonomic nervous tones. METHODS: 300 adolescents (male and female) aged 15-16 years living in the Polar (67°40' N) and Subpolar (64°30' N) northern regions of Russia are examined. Assessment of autonomic nervous tone was determined by the heart rate variability (HRV) and blood pressure parameters. After the initial analysis of these indicators, all subjects in both areas were further divided into groups with vagotonic, normotonic and sympathotonic types. Electroencephalogram (EEG) was recorded in the state of quiet wakefulness with closed eyes (16 standard monopolar leads). EEG characteristic were performed on the values of the amplitude and the index in each frequency band. All described changes were statistically significant atp < 0.05-0.001. RESULTS: According HRV and central hemodynamics among adolescents of the Polar North revealed an increase the proportion of individuals with a predominance ofsympathetic influences on cardiac activity (37.3%) and significant decrease the proportion ofpersons with a predominance of vagal influences (10%). A high activity of diencephalic subcortical brain structures in groups of normotonic and sympathotinic persons in the Polar region was revealed, which manifests itself in the form of increased levels of theta and alpha EEG-activity, as well as increased occurrence hypersynchronous EEG-types (50%). In adolescents-inhabitants of the Subpolar region occurs more intensive age optimization of neural processes then in adolescents- inhabitants of the Polar region. CONCLUSION: The predominance of sympathetic effects on the cardiac activity and higher activity of diencephalic subcortical brain structures in adolescents of the Polar region were revealed.

[The success of heart rate variability biofeedback parameters in persons with different levels of blood pressure].

OBJECTIVE: The aim was to determine the nature of cardiovascular reactions during a single session of heart rate variability (HRV) biofeedback in order to increase vagal effects on heart rhythm in patients with different initial levels of blood pressure (BP). PARTICIPANTS AND METHODS: 33 people with normal blood pressure (group I), 20 people with uncorrected arterial hypertension (AH) grade 1-2 (group II) and 22 people with AH grade 1-2 taking antihypertensive drugs (group III) were observed. The parameters of heart rate variability (HRV), BP and pulse aximetry in the initial stage, during a single HRV biofeedback session and after this session in order to increase the total power of the HRV spectrum (each stage 5 min). RESULTS: In patients of group II low success of HRV biofeedback session, a high sympathetic reactivity and reduced oxygen blood saturation were determined. A reactivity of vagal mechanism is more pronounced in persons of group III than in those of group II. It is reflected in a significant increase in their total power of the HRV spectrum compared to the initial values and in uptrend saturation levels during the biofeedback session. CONCLUSION: The ability to HRV biofeedback in order to increase the total power of the HRV spectrum for standard short recording (5 min) can be seen as a test to determine the safety reserves of vagal autonomic cardiovascular regulation in persons with increased blood pressure.

Comparative analysis of the response of microcirculation parameters and blood pressure to geomagnetic activity in healthy people.

We analyze the results of daily laser Doppler flowmetry monitoring of blood microcirculation parameters in 9 healthy volunteers performed in 2006-2009. Dependence of microcirculation and BP parameters on geomagnetic activity was analyzed separately in each volunteer (the influence of ambient temperature was previously excluded). Significantly increased parameters of microcirculation in response to higher geomagnetic activity were found in 4 volunteers (44%) and elevated BP in 1 volunteer; in other cases, no reaction was detected. It was shown that individual sensitivity to geomagnetic activity is proportional to its mean level during the period of measurement. Since blood perfusion volume in tissues directly depends on peripheral vascular resistance, we can conclude that under conditions of high geomagnetic activity microvascular tone varies to a greater extent than the tone of major vessels.

[Thyroid effect on brain activity in adolescents during heart rhythm biofeedback session].

Types of neurophysiologic and thyroid condition in 15-17-year old adolescents were studied for the purpose of heart rhythm biofeedback session effect by heart rhythm variability parameters. Changes of heart rhythm vegetative regulation activity modulate functional capacities of central vegetative regulation structures. The biofeedback training with heart rhythm variability parameters increases brain bioelectrical activity in different frequency ranges. The thyroid system modulates functional activity of vegetative regulation central structures uppermost at sympathotonic and thyreotropin increasing leads to increase of rhythm maker structure reactivity in brain.

[Relation between microcirculation parameters and Pc3 geomagnetic pulsations].

An individual analysis of long-term monitoring of microcirculation parameters of nine healthy volunteers showed that an increase in the geomagnetic activity led to an increase in tissue perfusion, variability of blood flow and growth of the amplitude of neurogenic and myogenic oscillations in four volunteers. It was found that the degree of microcirculation sensitivity to the level of geomagnetic activity values with time and is proportional to its average level in the period of measurement. A comparison of frequency ranges of oscillations of blood flow and variations of the geomagnetic activity shows that neurogenic and myogenic oscillations showing the highest sensitivity to the geomagnetic activity have the same frequency as geomagnetic Pc3 pulsations. The pulsations of this frequency range are excited mainly during geomagnetic disturbances, which may explain the correlation between the microcirculation parameters and the Kp index. The relation of the amplitude-frequency characteristics of Pc3-pulsations can explain the results obtained using the alternating magnetic fields.

[Vegetative cardiac rhythm regulation as a function of the morning melatonin levels in teenagers-northerners on a background of mental effort].

Seventy normal 12-15 y.o. teenagers in the Arkhangelsk oblast of Russia (in latitude 61 north) were investigated in the pubertal period (June, September, December). Immune-enzyme analysis was used to determine melatonin levels in blood serum at 8.30-9.30 a.m. In the daytime, cardiac rhythm variability was assessed on a background of mental calculation. It was shown that morning melatonin in blood serum of teenagers-northerners may be indicative of sympathetic cardiac rhythm regulation, particularly during mental effort. In June (the longest light period) the vegetative regulation had a minimal effect on mental effort. Dependence of the sympathetic activity on the level of morning melatonin in teenagers was conspicuous in September when the light period shortens.

[The age dynamic of hormonal levels in children living in different latitudes in European North].

An investigation simultaneously of hormonal profile in children of 10-16 years living in different latitudes and climato-ecological conditions in Russian European North (in the border of polar and middle latitudes) was performed. The increased thyrotropin level was revealed in 35% of children in the south (61 degrees North) and in 32% of children in the North (64 degrees 30' North). The thyroid hormones (thyroxin, triiodothyronine) are at low normative bound. Higher Insulin levels were observed in 28% of children living in the southen region especially in 50% of prepubertal boys. In 20% of children, higher cortisol levels were revealed mainly at the final puberty (35% of children).

[Photo dependent changes in the endocrine system activity in teenagers from different European North latitudes].

The comprehensive study was concerned with the within year dynamics of hormonal profile in two groups of teenagers (13-16 y.o.) resident in different latitudes and climate-ecological conditions of the European North of Russia (on the border of pre-polar and medium altitude regions).

[Regression analysis in the assessment of the state of the immune system]. / Regressionnyi analiz v otsenke sostoianiia immunnoi sistemy.

Optimal assessment of the immune status is one of the key problems in modern clinical immunology. Mathematical methods of diagnosis help select the minimal number of the most informative tests. Regression analysis of linear relationship permitted determining the regression coefficients and correlation pairs of equations which may be used for predicting, with few reference monoclonal sera (CD3 and CD5), the lacking cellular phenotype in immunogram. The resultant correlation pairs of equations were tried in a large number of examinees at laboratory of ecological immunology and are recommended for clinical diagnostical laboratories.