Developmental changes of BOLD signal correlations with global human EEG power and synchronization during working memory

In humans, theta band (5-7 Hz) power typically increases when performing cognitively demanding working memory (WM) tasks, and simultaneous EEG-fMRI recordings have revealed an inverse relationship between theta power and the BOLD (blood oxygen level dependent) signal in the default mode network during WM. However, synchronization also plays a fundamental role in cognitive processing, and the level of theta and higher frequency band synchronization is modulated during WM. Yet, little is known about the link between BOLD, EEG power, and EEG synchronization during WM, and how these measures develop with human brain maturation or relate to behavioral changes. We examined EEG-BOLD signal correlations from 18 young adults and 15 school-aged children for age-dependent effects during a load-modulated Sternberg WM task. Frontal load (in-)dependent EEG theta power was significantly enhanced in children compared to adults, while adults showed stronger fMRI load effects. Children demonstrated a stronger negative correlation between global theta power and the BOLD signal in the default mode network relative to adults. Therefore, we conclude that theta power mediates the suppression of a task-irrelevant network. We further conclude that children suppress this network even more than adults, probably from an increased level of task-preparedness to compensate for not fully mature cognitive functions, reflected in lower response accuracy and increased reaction time. In contrast to power, correlations between instantaneous theta global field synchronization and the BOLD signal were exclusively positive in both age groups but only significant in adults in the frontal-parietal and posterior cingulate cortices. Furthermore, theta synchronization was weaker in children and was--in contrast to EEG power--positively correlated with response accuracy in both age groups. In summary we conclude that theta EEG-BOLD signal correlations differ between spectral power and synchronization and that these opposite correlations with different distributions undergo similar and significant neuronal developments with brain maturation.

Child Aggression in a Post-Communist Country: Race and Gender Aspects in a Cross-Cultural Comparison

Gypsies represent approximately 2.5% of the Czech population, but are considerably over-represented among the unemployed, prisoners, schooldropouts, neglected children, etc. Together with racist attitudes on the part of the majority, this causes strong inter-ethnic tension and obviouseconomic, moral and political problems. This research studied the way in which this situation is reflected in peer relations between Gypsy andmajority children in schools. Six samples of children (totalling 2974 children aged 7-15, of whom 15% were Gypsies) were studied through peernomination, teacher assessment and self-reporting. Gypsy/non-Gypsy and gender dichotomies were correlated with measures of aggression,victimisation and acceptance/rejection. The results showed that Gypsy children, both boys and girls, were more likely to nominate their Gypsy peers as aggressors than they nominatemajority children, implying that they tend to direct their rejection toward their own kind. The number of Gypsy children in a class was also animportant factor with Gypsies being more likely to be accepted and less likely to appear aggressive when they were only one or two in a class, thanin a class where there was a greater number of Gypsy pupils. When whole classes were taken as the unit of analysis, Gypsy children were seen asmore likely to behave aggressively in class by their Gypsy and non-Gypsy counterparts as well as by their teachers. At the same time they aremuch less likely to become victims of aggression than are non-Gypsy children, both boys and girls. Mr. Rican also found that the acceptance/rejection patterns of Gypsy children betray their unsatisfactory socialisation. Among their peers, Gypsyor non-Gypsy, they tend to prefer aggressors or children who teachers describe as showing little discipline or effort to succeed at school. Partialcorrelation to assess the influence of seniority on aggressiveness provided a warning that the recent lengthening of compulsory school attendance islikely to bring an increase in aggressiveness. He believes that Gypsy ethnic identity has lost many of its important positive aspects, making itsnegative aspects more prominent and more dangerous. He does however find some possible ways for teachers to reinforce the positive aspects ofGypsy children's identities in order to support their socialisation at schools.

Power and Robustness of Linkage Tests for Quantitative Traits in General Pedigrees

There are numerous statistical methods for quantitative trait linkage analysis in human studies. An ideal such method would have high power to detect genetic loci contributing to the trait, would be robust to non-normality in the phenotype distribution, would be appropriate for general pedigrees, would allow the incorporation of environmental covariates, and would be appropriate in the presence of selective sampling. We recently described a general framework for quantitative trait linkage analysis, based on generalized estimating equations, for which many current methods are special cases. This procedure is appropriate for general pedigrees and easily accommodates environmental covariates. In this paper, we use computer simulations to investigate the power robustness of a variety of linkage test statistics built upon our general framework. We also propose two novel test statistics that take account of higher moments of the phenotype distribution, in order to accommodate non-normality. These new linkage tests are shown to have high power and to be robust to non-normality. While we have not yet examined the performance of our procedures in the context of selective sampling via computer simulations, the proposed tests satisfy all of the other qualities of an ideal quantitative trait linkage analysis method.

Age and gender-dependent alternative splicing of P/Q-type calcium channel EF-hand

Ca(v)2.1 Ca(2+) channels (P/Q-type), which participate in various key roles in the CNS by mediating calcium influx, are extensively spliced. One of its alternatively-spliced exons is 37, which forms part of the EF hand. The expression of exon 37a (EFa form), but not exon 37b (EFb form), confers the channel an activity-dependent enhancement of channel opening known as Ca(2+)-dependent facilitation (CDF). In this study, we analyzed the trend of EF hand splice variant distributions in mouse, rat and human brain tissues. We observed a developmental switch in rodents, as well as an age and gender bias in human brain tissues, suggestive of a possible role of these EF hand splice variants in neurophysiological specialization. A parallel study performed on rodent brains showed that the data drawn from human and rodent tissues may not necessarily correlate in the process of aging.

Power and Politics in Organizations

Aristotle made the observation that man is a political animal. Engineers often like to think they are above the fray when it comes to organizational politics, but most organizational theorists believe politics is a fundamental dynamic in any group. This paper examines the various ways that people use power within organizations to negotiate the political interactions in the work place.

Age and gender differences in health-related quality of life of children and adolescents in Europe: a multilevel analysis

OBJECTIVES: To determine age and gender differences in health-related quality of life (HRQOL) in children and adolescents across 12 European countries using a newly developed HRQOL measure (KIDSCREEN). METHODS: The KIDSCREEN-52 questionnaire was filled in by 21,590 children and adolescents aged 8-18 from 12 countries. We used multilevel regression analyses to model the hierarchical structure of the data. In addition, effect sizes were computed to test for gender differences within each age group. RESULTS: Children generally showed better HRQOL than adolescents (P < 0.001). While boys and girls had similar HRQOL at young age, girls' HRQOL declined more than boys' (P < 0.001) with increasing age, depending on the HRQOL scale. There was significant variation between countries both at the youngest age and for age trajectories. CONCLUSIONS: For the first time, gender and age differences in children's and adolescents' HRQOL across Europe were assessed using a comprehensive and standardised instrument. Gender and age differences exist for most HRQOL scales. Differences in HRQOL across Europe point to the importance of national contexts for youth's well-being.