Gender differences in chronic alcoholism: EEG analysis

Comparative analysis of spatial organization of cortical biopotentials of men (n = 120) and women (n = 75) suffering from alcoholism and persons without addiction to alcohol (control groups) was carried out. Gender differences in the EEG spatial parameters under study (linear spatial synchronization in the brain cortex, non-linear spatial disorder, EEG coherence, and spectral power) were shown to be markedly less pronounced between the control groups (68 women and 85 men) than between the alcohol addicts. The obtained data allow us to explain the known fact of more serious and "malignant" character of alcoholism in women than in men in terms of neurophysiology. In alcoholics, the synchronization of low-frequency oscillations (delta and theta) was higher, whereas the synchronization of the higher-frequency spectrum part (beta1 and beta2) was lower in women than in men. This fact can be a neurophysiological basis of more progredient inhibitory-degenerative processes in women.     

Indices of Coherence of EEG Rhythms in the Course of Cognitive Activity as Markers of Creative Thinking: Gender Specificity

According to the results of psychological testing, persons aged 18 to 21 years were divided into four groups, women and men with low and high productivity of divergent (creative, nonroutine) thinking (n = = 18 to 23). Results of EEG recording (19 leads) were used for calculation of the coherence coefficients for oscillations of the delta, theta, alpha1, alpha2, alpha3, beta, and gamma frequencies in lead pairs and estimation of integral indices of coherence within the anterior and posterior cortical regions and between these zones (interaction coefficients, IC1-IC3, respectively). EEG was recorded in the resting state and in the course of resolving convergent- and divergent-type cognitive test tasks. It was found that, during the performance of tests of both types, men with a higher productivity of divergent thinking demonstrated significantly higher values of IC1 (that characterizes the coherence in associative linkages within the anterior cortex) for oscillations of all EEG frequency ranges compared with the respective estimates for “low-creative” men. Similar increments were typical of the IC2 values for low- and midfrequency EEG rhythms (delta, theta, and alpha). At the same time, values of the “interregional” IC3 for theta, beta, and gamma activity in “high-creativity” men were significantly lower. In women of both groups (low and high creativity), such specificity of the IC1-IC3 patterns was practically not observed, i.e., the respective aspect demonstrated clear gender specificity. The sex of the subjects and type of the performed cognitive tests could not be considered factors significantly affecting the calculated absolute IC values. The observed specificities of integral coherence indices are probably associated with different strategies of the performance of cognitive tasks in men and women. Our findings allow us to believe that the above interrelations between integrated coherence indices can be used as EEG markers of high productivity of divergent thinking in men. The more flexible strategies of thinking in women are probably related to more variable neurophysiological cortical mechanisms (compared with those in men), and this type of organization is not clearly reflected in the pattern of intracortical interactions estimated by coherence indices.     

Sex differences in EEG power changes in retention of dichotically and monaurally presented verbal stimuli

EEG power mapping was used to study gender differences in hemispheric functional organization during memorizing dichotically and monaurally presented verbal information. Right-handed students (12 men and 14 women) participated in experiments. The EEG was recorded from 16 electrodes placed at homologous sites of the left and right brain hemispheres. Task-related changes in the thetal power in men differentiated between monaural presentations to different ears, i.e., situations of oppositely directed attention. In women the thetal power reactivity (the difference between the band power logarithms under baseline conditions and in task interval) differentiated between dichotic and monaural presentations of words, i.e., situations with different memory loads. Gender differences were also found in the alpha frequency band. Power changes in the alpha 1 band in all memory tasks and power changes in the alpha 2 were more evident in the right hemisphere in men but in the left hemisphere in women. In contrast, in the posterior temporal lead the alpha 2 power reactivity in men was higher in the right hemisphere, whereas in women the lateral differences were absent. As compared to men, the alpha 2 desynchronization in women was also more pronounced in posterior regions of both hemispheres. There were no gender differences in efficacy of memorizing. It is suggested that different processing strategies rather than different behavioral performance may be responsible for the revealed specific spatiotemporal EEG patterns.     

Dynamics of interhemispheric asymmetry during perception of verbal information in men and women: EEG analysis

Neurophysiological basis of gender differences in the dynamics of asymmetry in retrieval of dychotically presented verbal information was studied by mapping of EEG power and coherence during a prolonged dychotical test. Right-handed students (20 men and 11 women) participated in the experiments. It was shown that gender differences in the EEG were absent at the initial stage of testing and appeared at the final stage. At this stage, the asymmetry of the theta 2 EEG power was lower in men than in women, while the interhemispheric coherence in the theta 2- and alpha 1-bands was more pronounced in women than in men, mainly, in the caudal cortical regions. Thus, different cortical electrophysiological processes underlie similar behavioral effects (the same values of asymmetry coefficients of retrieval of syllables at the final stage of dichotic testing) in men and women.     

Strategy and results: Sex differences in electrographic correlates of verbal and figural creativity

Sex differences in electroencephalographic (EEG) correlates of creativity were studied using verbal and figural divergent tasks to be performed in accordance with the instructions to “give any solution” or “give an original solution.” The common effect was a greater activity of the right hemisphere, which did not depend on the sex, task type, or instructions for performance of the tasks. The α₂ and β₂ rhythms were the main EEG frequency correlates of creative thinking; the degree and sign of their reactivity depended on the aforementioned factors. Although the creative abilities in men and women were similar under test conditions, the EEG correlates of both figural and verbal tasks were sex-dependent. A high reactivity of the α₂ rhythm was more marked during verbal creative thinking in women; and that of the β₂ rhythm, during figural creative thinking in men. The instruction-related improvement of the critical selection of solutions was to a greater extent reflected by changes in the cortical activity, more pronounced in the frontal cortex in the women. Thus, the same creative productivity in men and women was mediated by different strategies of performance of both figural and verbal tasks, and the sex-related differences in these strategies remained even when the motivation for creativity was changed.     

Effect of inhalation therapy on the dynamics of electroencephalographic and rheoencephalographic indices in patients with vasomotor dystonia and with pathology of respiratory organs]

Dynamics of electro- and rheoencephalographic (EEG and REG) indices in patients with some forms of cephalgia (vegetovascular dystonia--VVD) as well as with chronic nonspecific pulmonary diseases has been studied under the effect of artificial mountain climate therapy conducted using a special chamber "Orotron" created by a collective of researchers from Academy of Sciences of Ukraine. The results of EEG and REG analysis reflect a general tendency to improvement of the bioelectrical brain activity and cerebral hemodynamics.     

Serum leptin in the development of insulin resistance and other disorders in the metabolic syndrome

The metabolic syndrome mostly represented by obesity and hyperinsulinaemia connected with insulin resistance, presents the main mechanism in the pathogenesis of cardiovascular disease. The aim of this study was to analyze the interrelations between several metabolic variables (including leptin) and factors related to insulin resistance in groups of both normal and non-diabetic hyperlipemic postmenopausal women and men of appropriate age, and to attempt to elucidate the gender differences. Two groups of patients (20 men, 20 women) with hypertriglyceridemia were compared with 30 individuals (10 men, 20 women) with normal serum triacylglycerols. Fasting serum leptin concentration, lipid parameters (triacylglycerols, HDL cholesterol, LDL cholesterol) and BMI were measured and compared with changes in insulin parameters influencing insulin resistance (HOMA IR, insulin, intact proinsulin, C-peptide). Statistical analysis was performed using SAS/STAT software including unpaired Student's t-test, Kolmogorov-Smirnov's test, Spearman's rank-order correlation and multiple regression analysis. In men, the insulin sensitivity correlates with leptin only. In women insulin sensitivity is markedly influenced by a complex of factors: leptin and lipid parameters. Increased insulin resistance in men is followed mainly by the increased correlations between leptin, HOMA IR and insulin parameters. In women correlations between leptin, HOMA IR and insulin parameters were smaller, but the inverse correlation with HDL cholesterol was stronger. In postmenopausal women and also in men, serum leptin concentration contributes to insulin resistance. However in women the effect of increase in serum triacylglycerols in contribution of insulin resistance seems to be more dominant.     

Gender differences in resting EEG related to Eysenk's Personality Traits

EEG mapping was used to study gender differences in hemispheric organization related to personality (40 male and 42 female subjects, the students 17-20 ages). The results showed, that each clearly defined personality trait (neuroticism, extraversion, psychoticizm and social conformity) characterized by special EEG pattern differenced on men and women groups. At the same time, more close interaction of gender and neuroticism was observed, but gender and extraversion were less connected. Neuroticism related patterns of coherence in the alpha2- and beta2-bands were associated with an activity changes in anterior cortex in men but posterior--in women, at that the positive correlations were observed in the beta2-band in the former case and negative ones in the second. There are two opposing tendencies of the interaction between extraversion and gender in a modulation of the resting theta-rhythm: an increase of cortex connections in men and decrease ones in women. The specificity of spatial-temporal EEG patterns in men associated mostly with a psychoticizm value but in women--with a social conformism. In either case these personality traits related to activity of frontal cortex in the left hemisphere.     

The impact of experimental instruction on changes in EEG power during verbal creative thinking in men and women

Features of EEG pattern during verbal creative thinking depending on experimental instruction were studied in men and women. Spectral power density was analyzed in six frequency bands (4-30 Hz). Performance of a creative task produced an increase in the power of theta (4-6 Hz) and beta2 (20-40 Hz) components and decrease in the power of alpha (8-13 Hz) and betal (13-20 Hz). Changes in the alpha and betal bands were observed, predominantly, in the posterior areas, whereas power of the thetal and beta2 bands increased in the anterior areas. Independently of instruction, women demonstrated greater synchronization in the theta1 band than men, whereas in men the desynchronization in the alpha2 band (10-13 Hz) was more pronounced. When the subjects were instructed to create original sentences, a widespread decrease in the EEG power was observed in the band of 8-30 Hz as compared to instruction "to create sentences". Thus, the instruction-related changes in EEG power were not gender-specific. They may reflect neural activity mediating selective attention.     

Sex specificity of the spatiotemporal organization of brain bioelectric potentials in adults and five- to six-year-old children in a state of quiet wakefulness

Correlation and coherence analyses of EEG recordings from 26 children aged five to seven years (12 boys and 14 girls) as compared to 33 adult subjects (18 women and 15 men) has been carried out to study the topical features of the spatial structure of EEG distant interactions. A higher level of EEG intrahemispheric interactions in the posttemporal and frontal areas of the left hemisphere has been found in men as compared to women in whom the prevalence of interhemispheric interactions due to the expressed EEG interactions in the bilaterally symmetric areas of both hemispheres has been found. A different type of sex-related differences in the systemic organization of interregional interactions of cortical potentials, as compared to adults, has been found in preschool children. In particular, a higher prevalence of EEG distant interactions has been found in those areas of the left hemisphere, the EEG interactions of which were higher in adult men. The data show that a distinct sexual dimorphism of interregional interactions of cortex potentials in adult subjects and children is formed due to the topology of the different EEG distant interactions differing in men and women. Investigations of the sex specificity of the spatiotemporal organization of brain bioelectric potentials in children can promote understanding of the sexual identity role in development of human brain systemic activity.     

Differences in Sensitivity to Cold in Japanese Men and Postmenopausal Women Aged ≥50 Years

Background: Sensitivity to cold is associated with several factors, such as aging, sex, and body composition. However, no previous studies have examined the differences in sensitivity to cold in men and women or the association of hormonal levels with sensitivity to cold.Objective: The aim of the present study was to clarify both the change in sensitivity to cold with aging and the difference in sensitivity to cold between men and women. Associations were also examined between circulating hormonal concentrations and the changes with aging and differences in sensitivity.Methods: This population-based cohort study enrolled healthy Japanese men and women aged ≥ 50 years. A standardized 210-item health questionnaire was used to obtain information on symp- toms of sensitivity to cold. Serum concentrations of luteinizing hormone, follicle-stimulating hor- mone (FSH), estradiol, testosterone, dehydroepiandrosterone sulfate, and sex hormone-binding globu- lin (SHBG) were measured.Results: Of the 154 men and 180 women enrolled in this study, more women than men had sensitivity to cold. Whereas the percentage of men who had sensitivity to cold significantly increased with aging (P < 0.05), the percentage of women who had sensitivity to cold was already high (23.7%) at 50 to 60 years of age and did not change with aging. In men, advancing age and low body mass index (BMI) were significantly associated with sensitivity to cold (P < 0.05); however, age and BMI in women were not similarly associated. In addition, the effect of sex after adjustment for age was significant (P < 0.05), and there was also a numeric but nonsignificant effect of sex after adjustment for BMI. In men, low serum levels of the gonadal hormone FSH were significantly associated with sensitivity to cold in logistic analysis, but this association was nonsignificant after multivariate analysis. Serum concentrations of gonadal hormones and SHBG in women were not associated with sensitivity to col.Conclusions: The association of age with sensitivity to cold was different in men and women; the association of BMI with sensitivity to cold might be different in men and women. In addition, these changes in sensitivity to cold were not associated with circulating hormonal concentrations.     

Background activity of the brain in healthy mental aging

The EEG mapping study tested age-related changes in power of EEG rhythms from delta to gamma ranges under healthy cognitive aging associated with preserved cognitive abilities and involvement in complex professional activity. 32 subjects of higher age group (HAG, mean age 65.1 +/- 1.18, 14 men and 18 women) and 33 subjects of lower age group (LAG mean age 22.1 +/- 0.38, 18 men and 15 women) participated in the study. Mean power of slow (delta, theta and alpha2) activity decreased and of fast activity (beta, gamma) increased as subject age increased. Compared to subjects of LAG subjects of HAG displayed a reduction in heterogeneity of EEG activity across recording sites. Centro-temporal gradients of power for frequency ranges from delta to beta2 and frontoparietal gradients and hemispheric asymmetry for alpha and beta1 rhythms were smoothed in subjects of HAG. These results suggest that observed age-related changes in baseline EEG may be the prerequisite for compensatory neural recruitment that may be associated as with allocation of more resources in cognitive processes so with reorganization of cortical networks including areas susceptible to physiological changes with aging.     

Epigenetic regulation of REG1A and chemosensitivity of cutaneous melanoma

Regenerating gene 1A (REG1A) plays an important role in tissue regeneration and in cell proliferation in epithelium origin tumors; however, its role in melanoma has not been explored in details. The objective of this study was to identify whether REG1A is expressed in cutaneous melanoma and if REG1A expression status can predict prognosis in cutaneous melanoma patients with metastasis. We also determined whether epigenetic regulation of the promoter region regulates REG1A expression. AJCC stage III cutaneous melanoma specimens with clinically well annotated stage III lymph node melanoma metastasis tissue microarray were assessed by IHC. MALDI-TOF-mass spectrometry and HM450K array were used to identify REG1A promoter region CpG site methylation. Chemotherapeutic agent response by melanoma cells as related to REG1A protein expression was assessed. Post-surgery melanoma patients followed by adjuvant chemotherapy with high REG1A expression had a significantly better prognosis (disease-specific survival) compared with patients with low REG1A expression (log rank test; p = 0.0013). The demethylating reagent 5-Aza-2′-deoxycytidine activated REG1A promoter region resulting in enhanced REG1A mRNA and protein expression in melanoma cell lines. Promoter region CpG methylation was shown to regulate REG1A expression in melanoma cells. Moreover, melanoma lines with high REG1A mRNA expression were more susceptible to Dacarbazine and Cisplatin, as compared with those with low REG1A mRNA expression. In conclusion, REG1A expression status may be useful as a biomarker in melanoma patients for sensitivity to these chemotherapeutic agents. The epigenetic regulation of the REG1A promoter region may offer a potential therapeutic approach to improve chemotherapy for metastatic melanoma patients.     

Hemispheric Specialization Varies with EEG Brain Resting States and Phase of Menstrual Cycle

A growing body of behavioral studies has demonstrated that women’s hemispheric specialization varies as a function of their menstrual cycle, with hemispheric specialization enhanced during their menstruation period. Our recent high-density electroencephalogram (EEG) study with lateralized emotional versus neutral words extended these behavioral results by showing that hemispheric specialization in men, but not in women under birth-control, depends upon specific EEG resting brain states at stimulus arrival, suggesting that hemispheric specialization may be pre-determined at the moment of the stimulus onset. To investigate whether EEG brain resting state for hemispheric specialization could vary as a function of the menstrual phase, we tested 12 right-handed healthy women over different phases of their menstrual cycle combining high-density EEG recordings and the same lateralized lexical decision paradigm with emotional versus neutral words. Results showed the presence of specific EEG resting brain states, associated with hemispheric specialization for emotional words, at the moment of the stimulus onset during the menstruation period only. These results suggest that the pre-stimulus EEG pattern influencing hemispheric specialization is modulated by the hormonal state.     

Visceral fat area cutoff for the detection of multiple risk factors of metabolic syndrome in Japanese: the Hitachi Health Study

The relationships between metabolic risk factors and abdominal fat distribution determined using computed tomography (CT) are poorly defined in large populations. We investigated the cutoff values of the visceral fat area (VFA) to detect subjects with multiple risk factors of metabolic syndrome (MS) by sex and age groups, and attempted to examine whether sex- and age-specific cutoff values are needed. The subjects of this study were 11,561 Japanese men and women who participated in the Hitachi Health Study, received CT examination, and answered questionnaires on lifestyles between 2004 and 2009. VFA and waist circumference were measured using CT. The VFA cutoff values yielding an 80% sensitivity for the detection of multiple risk factors of MS were typically smaller among men under the age of 40 years (<40 years vs. ≥40 years; 86.4 cm(2) vs. 103.9 cm(2)). The area under the receiver operator characteristic curve of VFA for the detection tended to decrease according to age (P = 0.056 and P = 0.020 for trends in men and women). Age- and sex-specific cutoff values are needed. The sensitivity of the subjects under the age of 40 years is relatively smaller (70.0% for men and 60.0% for women) compare to other age groups when the same cutoff value is used regardless of age (e.g., cutoff value calculated to correspond to 80% sensitivity for subjects of all ages). Therefore, a smaller VFA cutoff point should be used among men under the age of 40 years.     

Sleep impairments in healthy seniors: roles of stress, cortisol, and interleukin-1 beta

Study Objectives: Increased stress responsivity and a longer-lasting glucocorticoid increase are common findings in aging studies. Increased cortisol levels at the circadian nadir also accompany aging. We used 24h free urine cortisol to assess these age changes in healthy seniors. We hypothesized that free cortisol levels would explain individual differences in age-related sleep impairments. Design: The study compared sleep, cortisol, and sleep-cortisol correlations under baseline and “stress” conditions in men and women. Setting: Subjects were studied in the General Clinical Research Center under baseline conditions and a mildly stressful procedure (24h indwelling intravenous catheter placement). Participants: Eighty-eight healthy, nonobese subjects (60 women and 28 men) from a large study of successful aging participated in the study. Mean ages were 70.6 (±6.2) and 72.3 (±5.7) years for women and men, respectively. Measurements: The 24h urines were collected for cortisol assay (radioimmunoassay [RIA]); blood was sampled at three diurnal time points for assay (enzyme-linked immunosorbent assay [ELISA]) of interleukin-1 (IL-1) beta; sleep architecture and sleep electroencephalograms (EEGs) were analyzed (after an adaptation and screening night) on baseline and stress nights via polysomnography and EEG power spectral analysis. Results: Healthy older women and men with higher levels of free cortisol (24h urine level) under a mild stress condition had impaired sleep (lower sleep efficiency; fewer minutes of stages 2, 3, and 4 sleep; more EEG beta activity during non-rapid eye movement sleep [NREM] sleep). Similar results were obtained when stress reactivity measures were used (cortisol and sleep values adjusted for baseline values), but not when baseline values alone were used. Gender differences were apparent: Men had higher levels of free urine cortisol in both baseline and mild stress conditions. Cortisol and sleep correlated most strongly in men; cortisol stress response levels explained 36% of the variance in NREM sleep stress responses. In women, but not men, higher cortisol was also associated with earlier time of arising and less REM sleep. Higher cortisol response to stress was associated with increased circulating levels of IL-1β, explaining 24% of the variance in a subset of women. Conclusion: These results indicate that free cortisol (as indexed by 24h urine values) can index responses to mild stress in healthy senior adults, revealing functional correlations (impaired sleep, earlier times of arising, more EEG beta activity during sleep, more IL-1β) and gender differences. (Chronobiology International, 17(3), 391-404, 2000)     

Atmospheric pressure and suicide attempts in Helsinki,Finland

The influence of weather on mood and mental health is commonly debated. Furthermore, studies concerning weather and suicidal behavior have given inconsistent results. Our aim was to see if daily weather changes associate with the number of suicide attempts in Finland. All suicide attempts treated in the hospitals in Helsinki, Finland, during two separate periods, 8 years apart, were included. Altogether, 3,945 suicide attempts were compared with daily weather parameters and analyzed with a Poisson regression. We found that daily atmospheric pressure correlated statistically significantly with the number of suicide attempts, and for men the correlation was negative. Taking into account the seasonal normal value during the period 1971–2000, daily temperature, global solar radiation and precipitation did not associate with the number of suicide attempts on a statistically significant level in our study. We concluded that daily atmospheric pressure may have an impact on suicidal behavior, especially on suicide attempts of men by violent methods (P < 0.001), and may explain the clustering of suicide attempts. Men seem to be more vulnerable to attempt suicide under low atmospheric pressure and women under high atmospheric pressure. We show only statistical correlations, which leaves the exact mechanisms of interaction between weather and suicidal behavior open. However, suicidal behavior should be assessed from the point of view of weather in addition to psychiatric and social aspects.     

Relationship between Insulin Resistance and Coronary Artery Calcium in Young Men and Women

Background

The gender disparity in cardiovascular disease (CVD) risk is greatest between young men and women. However, the causes of that are not fully understood. The objective of this study was to evaluate the relationship between insulin resistance and the presence of coronary artery calcium (CAC) to identify risk factors that may predispose young men and women to CVD.

Methodology/Principal Findings

Insulin resistance and CVD risk factors were examined in 8682 Korean men and 1829 women aged 30–45 years old. Insulin resistance was estimated using the homeostasis model assessment of insulin resistance (HOMA-IR), and CAC was measured using computed tomography. Women were less likely to be insulin resistant (upper quartile of HOMA-IR, 18% vs. 27%, p<0.001) and had a lower prevalence of CAC (1.6% vs. 6.4%, p<0.001). Even when equally insulin resistant men and women were compared, women continued to have lower prevalence of CAC (3.1% vs. 7.2%, p = 0.004) and a more favorable CVD risk profile. Finally, after adjustment for traditional CVD risk factors, insulin resistance remained an independent predictor of CAC only in men (p = 0.03).

Conclusions/Significance

Young women have a lower risk for CVD and a lower CAC prevalence compared with men. This favorable CVD risk profile in women appears to occur regardless of insulin sensitivity. Unlike men, insulin resistance was not a predictor of CAC in women in this cohort. Therefore, insulin resistance has less impact on CVD risk and CAC in young women compared with men, and insulin resistance alone does not explain the gender disparity in CVD risk that is observed at an early age.     

On the differences between maximum likelihood and regression interval mapping in the analysis of quantitative trait loci

The differences between maximum-likelihood (ML) and regression (REG) interval mapping in the analysis of quantitative trait loci (QTL) are investigated analytically and numerically by simulation. The analytical investigation is based on the comparison of the solution sets of the ML and REG methods in the estimation of QTL parameters. Their differences are found to relate to the similarity between the conditional posterior and conditional probabilities of QTL genotypes and depend on several factors, such as the proportion of variance explained by QTL, relative QTL position in an interval, interval size, difference between the sizes of QTL, epistasis, and linkage between QTL. The differences in mean squared error (MSE) of the estimates, likelihood-ratio test (LRT) statistics in testing parameters, and power of QTL detection between the two methods become larger as (1) the proportion of variance explained by QTL becomes higher, (2) the QTL locations are positioned toward the middle of intervals, (3) the QTL are located in wider marker intervals, (4) epistasis between QTL is stronger, (5) the difference between QTL effects becomes larger, and (6) the positions of QTL get closer in QTL mapping. The REG method is biased in the estimation of the proportion of variance explained by QTL, and it may have a serious problem in detecting closely linked QTL when compared to the ML method. In general, the differences between the two methods may be minor, but can be significant when QTL interact or are closely linked. The ML method tends to be more powerful and to give estimates with smaller MSEs and larger LRT statistics. This implies that ML interval mapping can be more accurate, precise, and powerful than REG interval mapping. The REG method is faster in computation, especially when the number of QTL considered in the model is large. Recognizing the factors affecting the differences between REG and ML interval mapping can help an efficient strategy, using both methods in QTL mapping to be outlined.     

Sex differences of spatial-temporal organization of biopotentials of the brain in adults and child 5-6 years old

Research of topical features of spatial structure of EEG distant relationships has been performed with correlation and coherent analyses of EEG for 26 children of 5-6 years old (12 boys and 14 girls) in comparison to the data at 33 adult subjects (15 men and 18 women). Men have much higher level of EEG intrahemispherical relations of posttemporal and frontal regions of the left hemisphere whereas women have the higher level prevalence of interhemispheric interactions, especially of bilateral-symmetrical arials of both hemispheres. Preschoolers have another character of sex differences in the system organization of inter-regional interactions of brain biopotentials than adults. In particularly the girls have exceeding of EEG distant relations in the same zones of left hemispheres, where at men such relations have exceeding in comparison with woman. The obtained data shows that the pronounced sexual dimorphism of inter-regional interactions of cortical biopotentials at adults and at children is formed, first of all, owing to of EEG distant relations topology differing in males and females subject. Investigation sex differences of spatial-temporal organization of biopotentials of the brain in children can promote forming of more hole and deep understanding of role of sex factor in development of human brain system activity.