White matter makes up about fifty percent of the human brain. Maturation of white matter accompanies biological development and undergoes the most dramatic changes during childhood and adolescence. Despite the advances in neuroimaging techniques, controversy concerning spatial, and temporal patterns of myelination, as well as the degree to which the microstructural characteristics of white matter can vary in a healthy brain as a function of age, gender and cognitive abilities still exists. In a selective review we describe methods of assessing myelination and evaluate effects of age and gender in nine major fiber tracts, highlighting their role in higher-order cognitive functions. Our findings suggests that myelination indices vary by age, fiber tract, and hemisphere. Effects of gender were also identified, although some attribute differences to methodological factors or social and learning opportunities. Findings point to further directions of research that will improve our understanding of the complex myelination-behavior relation across development that may have implications for educational and clinical practice.

Nearly 15 million infants are born preterm every year. Research shows that compared to their full-term peers, individuals born preterm are more likely to have lower academic scores and be less wealthy later in life. Some suggest that brain connectivity as measured by diffusion tensor imaging (DTI) may underly these results. Critically, these differences have not been substantiated quantitatively. We performed quantitative meta-analyses to evaluate overarching patterns from articles that reported DTI metrics from the corpus callosum (CC), the largest white matter structure in the brain, in neonates and children/adolescents who were born pre-term and full-term. The DTI literature was reviewed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Two meta-analyses, considering publication bias and study heterogeneity, were performed onfractional anisotropy scores from the CC from eligible articles that scanned individuals at 39.9±1.1 weeks (i.e., neonates) and 14±4.13 years of age (i.e., children/adolescents). Meta-analyses for neonates and children/adolescents revealed no significant differences between those born preterm and full-term in the CC. Children/adolescents samples were characterized by significant publication bias and high interstudy heterogeneity, whereas the neonate samples were not. The findings challenge the current state of understanding of white matter microstructure in the CC related to preterm birth. Results highlight the need for further research to better understand the dynamics among factors that can influence neural development in preterm children.

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The neurophysiological mechanisms underlying social behavior are still poorly understood. An increasing number of international studies uses hyperscanning for simultaneous recording of brain activation from several individuals during social interaction. Despite the outstanding school of Russian social psychology, the number of studies investigating the neurophysiological basis of social behavior in humans is still limited in the Russian literature. The goal of the present work was to review the hyperscanning methods, i.e., methods for simultaneous recording of physiological indices used to investigate inter-brain synchronization during social interactions. The paper discusses methods for recording and analysis of multi-subject data representing the changes in brain activity, existing experimental and naturalistic models, key results, as well as applied and fundamental aspects of the implementation of this technique in social psychology and neuroscience. Introduction of the methods which allow for a better understanding of physiological mechanisms of social interactions may significantly contribute to the development of innovative approaches to improving educational process, teamwork in various professional areas, social welfare, and psychosomatic health of people.