Peculiarities of interrelations of activation levels of frontal,temporal, and parietal cortex by parameters of ultraslow biopotentials in the 4–5-year-old children with the age norm and delayed speech development

Possibilities were considered of the integrative approach with use of parameters of the ultraslow informational-control brain and organism system in studying physiological grounds of the rest state, which determine structure and quality of the adaptive behavior. By using the proposal approach there were analyzed results of comparative studies of peculiarities of the wakefulness level, of its autonomous, hemodynamic, and oxygen-depended energy maintenance, and of activation levels and their interrelations in neocortical outputs of the brain systems of the frontal, temporal-parietal, and parietal cortex participating in organization of the higher integrative functions and speech in the 4–7-year-old children with the age norm of the general psychic and verbal development and with delay of the neuropsychic development, including development of speech.Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 40, No. 5, 2004, pp. 455–468.Original Russian Text Copyright © 2004 by Ilyukhina, Krivoshchapova, Matveev, Ponomareva, Shaptilei.To the 100-Anniversary of N. N. Traugott     

Visuo-motor synchronization in children of 7-8 years old

The group of 22 children of 7-8 years old and the group of 17 adults participated in the experiment in which they were asked to synchronize their movements (pressing a button) with an isochronous sequence of visual stimuli. The period of the sequence was varied between 500 to 2000 ms with the 300 ms step. Two successive phases of visuo-motor synchronization were studied: the synchronization phase and the initiation phase which corresponds to the process of transition between reacting to a visual stimulus and the stable synchronization. The initiation phase was characterized by the shape and duration of the asynchrony time course (relaxation curve). The statistical properties of asynchrony were analyzed in the framework of the phase correction of the central timer. It is shown that (1) the range of successful visuo-motor synchronization is narrower in children of 7-8 than in adults and it spans from 600-700 ms to approx. 1700 Mc; (2) The initiation phase lasts about the same time in children of 7-8 and adults and typical shapes of individual relaxation curves are similar in both adults and children. (3) Although the statistical properties of asynchrony are comparable in children and adults, the mechanism of phase correction of the central timer operates with a lower value of the correction gain factor in children than in adults. In children, the phase correction process is also characterized by a substantially higher level of the central and motor noise which leads to a higher asynchrony variability and more frequent and longer lasting synchronization losses.     

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.     

Lower and upper limb length of urban and rural 7-11 years old Turkish school children

This study was carried out on 779 male and 755 female 7-11 years old children, who are students of the primary schools in Diyarbakir city center and center connected areas. The average values of lower and upper extremity lengths of children in center and rural primary schools have been compared, and the results have been analyzed with the Student t-test. The relation between lower and upper extremity length averages and height is shown by correlation coefficients. It is observed that in the 11 years old boy's group and in the 9 years old girl's group of the center primary schools the total arm lengths are longer (p < 0.01). Upper and lower extremity lengths are increasing parallel to height. Iliospinal heights are obviously longer in the 11 year old group of boys and the 7, 9 and 11 year group of girls in the center primary school.     

Age-related specificity of the frontal and temporoparietal cortex activation levels in three-to seven-year-old children

The results of studies on the specificity of formation of the frontal and temporoparietal cortex activation levels in children aged three, four to five, and six to seven years with a normal development of higher mental functions and speech are summarized. The parameters of the stable millivolt-range potential recorded from the head surface were used for this purpose. The results obtained are compared with published data on the specificity of the morphological and functional organization of the brain and the level of development of the slow information control system estimated on the basis of EEG parameters at the same ages. The estimation of the contribution of the brain superslow information control system by one of the basic parameters of state makes it possible to determine, in quantitative terms, (1) the characteristics of the formation of activation levels of cerebral systems involved in the regulation of the resting state, higher mental functions, and speech at different stages of ontogeny; (2) (on the basis of the stable-potential variance) the degrees of freedom of the activation levels of the cerebral systems studied, which determine their regulatory capacity at different ages; and (3) the degree of development of the system-forming mechanisms combining all these systems into an integrated whole at a certain stage of ontogeny (from six to seven years of age).     

Safety, reactogenicity and immunological activity of a group A meningococcal polysaccharide vaccine for children 1-4 years old

In the controlled trial carried out among children aged 1-4 years, the safety, reactogenicity and immunological potency of group A meningococcal polysaccharide vaccine produced at the Gabrichevski? Research Institute of Epidemiology and Microbiology (Moscow) were studied. The vaccine under test was introduced in two doses containing 15 and 25 micrograms of meningococcal polysaccharide. Both doses were shown to be safe, faintly reactogenic and immunologically potent. Systemic reactions were manifested by a transient rise in temperature to subfebrile levels in 19% and to 37.8-38.2 degrees C in 4.7% of the vaccinees. The temperature dropped to the normal level by the end of the first day following vaccination. At the site of injection skin hyperemia up to 2-3 cm in diameter was registered in 74% and up to 5-6 cm in diameter, in 6% of the vaccinees. Hyperemia disappeared on day 2 after vaccination. The production of antibodies to group A meningococcal polysaccharide occurred in response to both doses under test, and the elevated antibody level (in comparison to the initial one) was retained perceptibly longer in response to a dose of 25 micrograms; this dose, considering its low reactogenicity, was chosen as the optimal dose for children of the above age group.     

Changes in cardiorhythm and its stochastic parameters in first-graders with normal neuropsychological development and in children with speech disorders during performance of intellectual activity

Influence of positive and negative motivation on the performance efficiency and some stochastic characteristics of RR-interval fluctuations in speech association experiment was studied in two groups of pupils of the first class: normally developing children and children with speech deviations. It was shown that children with normal development achieve their maximal productivity mostly under the influence of their inner motivation without external stimulation, while for achieving the maximal productivity by children with speech deviations the positive external motivation is required. Baseline ECG recordings in two groups of children significantly differed only in the standard error of the RR-intervals that was decreased in the deviant children. Under conditions of positive motivation, the maximal intellectual productivity in both groups of children was achieved at significantly different values of the fractal index beta. The findings are discussed in terms of the influence of motivation on the verbal performance and concomitant adaptation.     

Evaluation and reproduction of time intervals in 7-10-year old children

We examined 200 children at the age of 7-10 (100 boys and 100 girls). The subjects had to estimate and reproduce time intervals in the range of 15-90 s. It was found that the children reproduced the intervals better and with lesser deviations than they estimated the intervals. The precision of time estimation increased with age and was best in ten-ear-old children. The findings confirm the authors' hypothesis about the "active" and "passive" time perception.     

Functional organization of the brain cortical areas at rest condition in children 5, 6 and 7 years old

Functional connectivity at rest was studied in children of 5, 6 and 7 years old. Connection strengths were estimated using coherence function taken at the frequencies of the major EEG rhythms. Factor analysis of the raw coherence data revealed 4 different cortico-cortical functional connectivity patterns. These patterns are stable across the studied age span although particular functional links may change reflecting the general trend of heterchronous maturation of the cortex.     

Cortical integration in the visual system of the macaque monkey: large-scale morphological differences in the pyramidal neurons in the occipital, parietal and temporal lobes.

Layer III pyramidal neurons were injected with Lucifer yellow in tangential cortical slices taken from the inferior temporal cortex (area TE) and the superior temporal polysensory (STP) area of the macaque monkey. Basal dendritic field areas of layer III pyramidal neurons in area STP are significantly larger, and their dendritic arborizations more complex, than those of cells in area TE. Moreover, the dendritic fields of layer III pyramidal neurons in both STP and TE are many times larger and more complex than those in areas forming 'lower' stages in cortical visual processing, such as the first (V1), second (V2), fourth (V4) and middle temporal (MT) visual areas. By combining data on spine density with those of Sholl analyses, we were able to estimate the average number of spines in the basal dendritic field of layer III pyramidal neurons in each area. These calculations revealed a 13-fold difference in the number of spines in the basal dendritic field between areas STP and V1 in animals of similar age. The large differences in complexity of the same kind of neuron in different visual areas go against arguments for isopotentiality of different cortical regions and provide a basis that allows pyramidal neurons in temporal areas TE and STP to integrate more inputs than neurons in more caudal visual areas.