Search results for "MATURATION"
showing 10 items of 102 documents
Postnatal increases in axonal conduction velocity of an identified Drosophila interneuron require fast sodium, L-type calcium and shaker potassium ch…
2019
Abstract During early postnatal life, speed up of signal propagation through many central and peripheral neurons has been associated with an increase in axon diameter or/and myelination. Especially in unmyelinated axons postnatal adjustments of axonal membrane conductances is potentially a third mechanism but solid evidence is lacking. Here, we show that axonal action potential (AP) conduction velocity in the Drosophila giant fiber (GF) interneuron, which is required for fast long-distance signal conduction through the escape circuit, is increased by 80% during the first day of adult life. Genetic manipulations indicate that this postnatal increase in AP conduction velocity in the unmyelina…
Developmental dissociation between visual and auditory repetition priming: The role of input lexicons
2000
Contrasting theories posit the source of verbal repetition priming in the activation of preexisting memory representations in the input lexicons or, alternatively, in the formation of new episodic memory traces. The two hypotheses predict different outcomes from the comparison of developmental rates of visual and auditory verbal repetition priming. The activation theory predicts a developmental dissociation between the early maturation of auditory priming and the later maturation of visuo-verbal priming, contingent upon the discrepant acquisition rates of the auditory and visual input lexicons. The episodic theory, instead, does not make such an assumption. We administered visual and audito…
Relative Age Effect in the Sport Environment. Role of Physical Fitness and Cognitive Function in Youth Soccer Players
2019
The need to achieve short-term competitive outcomes in sports may influence the emergence of talent selection strategies, which could bias individuals&rsquo
Effect of delayed breeding on the reproductive performance of female mice
2003
The aim of the present study was to determine, in the mouse, whether maintaining females as virgins until an advanced reproductive age was associated with decreased reproductive performance and reproductive lifespan compared with females of the same age that were first mated with males at an earlier reproductive age. Randomly selected virgin hybrid (C57BL/6JIco female × CBA/JIco male) female mice were housed individually with a randomly selected 12- to 14-week-old hybrid male either at the age of 28 weeks (normal breeding group; n = 20) or 51 weeks (delayed breeding group; n = 23) for the rest of their reproductive life. Females were checked once daily to determine the day of parturition an…
Children show hemispheric differences in the basic auditory response properties
2019
Auditory cortex in each hemisphere shows preference to sounds from the opposite hemifield in the auditory space. Besides this contralateral dominance, the auditory cortex shows functional and structural lateralization, presumably influencing the features of subsequent auditory processing. Children have been shown to differ from adults in the hemispheric balance of activation in higher-order auditory based tasks. We studied, first, whether the contralateral dominance can be detected in 7- to 8-year-old children and, second, whether the response properties of auditory cortex in children differ between hemispheres. Magnetoencephalography (MEG) responses to simple tones revealed adult-like cont…
Cognitive flexibility modulates maturation and music-training-related changes in neural sound discrimination
2015
Previous research has demonstrated that musicians show superior neural sound discrimination when compared to non-musicians, and that these changes emerge with accumulation of training. Our aim was to investigate whether individual differences in executive functions predict training-related changes in neural sound discrimination. We measured event-related potentials induced by sound changes coupled with tests for executive functions in musically trained and non-trained children aged 9-11 years and 13-15 years. High performance in a set-shifting task, indexing cognitive flexibility, was linked to enhanced maturation of neural sound discrimination in both musically trained and non-trained chil…
Effect of dietary supplementation with a mixture of Vitamins C and E on fertilization of tertiary butyl hydroperoxide-treated oocytes and parthenogen…
2002
The present study aims to analyze the effect of dietary supplementation with a mixture of Vitamins C and E on fertilization and later development of tertiary butyl hydroperoxide (tBH)-treated mouse oocytes and on parthenogenetic activation of freshly ovulated mouse oocytes. We fed hybrid mice a standard diet supplemented or not supplemented with Vitamins C and E from the first day of weaning until the age of 12 weeks. We noted no significant effect of diet on fertilization rate, percentage of total and hatching blastocysts, total number of cells, mitotic index and percentage of apoptotic nuclei at 120 h post-insemination of oocytes incubated for 15 min in the presence of 0, 1, 5 and 10 micr…
Bupropion induces social anxiety in adolescent mice: Influence of housing conditions
2016
Abstract Background The antidepressant bupropion has received increasing attention as a pharmacological tool to treat addiction although little is known about its effects on social behaviour in adolescents. The present study aimed to evaluate if environmental housing conditions influence bupropion’s actions on social behaviour of adolescent mice. Methods Mice were either group- or individually housed for 2-weeks and then randomly divided into 2 cohorts: half of the mice remained in the initial housing condition and the other half were changed to isolated conditions for further 2-weeks. The following groups were compared: isolated/isolated (ISO/ISO), isolated/group-housed (ISO/GR), group-hou…
Gonadotropin Hormone Modulation of Testosterone, Immune Function, Performance, and Behavioral Trade‐Offs among Male Morphs of the Lizard Uta stansbur…
2008
Sexual selection predicts that trade-offs maintain trait variation in alternative reproductive strategies. Experiments often focus on testosterone (T), but the gonadotropins follicle-stimulating hormone and luteinizing hormone may provide a clearer understanding of the pleiotropic relationships among traits. We assess the activational role of gonadotropins on T and corticosterone regulation in traits expressed by polymorphic male side-blotched lizards Uta stansburiana. Gonadotropins are found to enhance and suppress multiple physiological, morphological, and behavioral traits independently, as well as indirectly via T, and we demonstrate selective trade-offs between reproduction and surviva…
Early maturation and substance use across adolescence and young adulthood: A longitudinal study of Finnish twins.
2017
AbstractEarly maturation, indexed by pubertal development (PD), has been associated with earlier initiation and greater frequency of adolescent substance use, but this relationship may be biased by confounding factors and effects that change across development. Using a population-based Finnish twin sample (N = 3,632 individuals), we conducted twin modeling and multilevel structural equation modeling of the relationship between PD and substance use at ages 12–22. Shared environmental factors contributed to early PD and heavier substance use for females. Biological father absence was associated with early PD for boys but not girls, and did not account for the relationship between PD and subst…