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Brain Maturation (brain + maturation)
Selected AbstractsTurner syndrome: Neuroimaging findings: Structural and functionalDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 4 2009Ronan Mullaney Abstract Neuroimaging studies of Turner syndrome can advance our understanding of the X chromosome in brain development, and the modulatory influence of endocrine factors. There is increasing evidence from neuroimaging studies that TX individuals have significant differences in the anatomy, function, and metabolism of a number of brain regions; including the parietal lobe; cerebellum, amygdala, hippocampus; and basal ganglia; and perhaps differences in "connectivity" between frontal and parieto-occipital regions. Finally, there is preliminary evidence that genomic imprinting, sex hormones and growth hormone have significant modulatory effects on brain maturation in TS. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:279,283. [source] The neurobiological profile of girls with ADHDDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 4 2008E. Mark Mahone Abstract Since boys are more commonly diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) than girls, the majority of theories and published research studies of ADHD have been based on samples comprised primarily (or exclusively) of boys. While psychosocial impairment in girls with ADHD is well established, the neuropsychological and neurobiological basis of these deficits is less consistently observed. There is growing evidence that boys' and girls' brains develop and mature at different rates, suggesting that the trajectory of early anomalous brain development in ADHD may also be sex-specific. It remains unclear, however, whether earlier brain maturation observed in girls with ADHD is protective. In this review, we outline the current theory and research findings that seek to establish a unique neurobiological profile of girls with ADHD, highlighting sex differences in typical brain development and among children with ADHD. The review highlights findings from neurological, neurocognitive, and behavioral studies. Future research directions are suggested, including the need for longitudinal neuroimaging and neurobehavioral investigation beginning as early as the preschool years, and continuing through adolescence and adulthood, with consideration of identified sex differences in the development of ADHD. © 2008 Wiley-Liss, Inc. Dev Disabil Res Rev 2008;14:276,284. [source] Changes in mid-to-late latency auditory evoked reponses in the chicken during neural maturationDEVELOPMENTAL PSYCHOBIOLOGY, Issue 1 2010Rebbekah Atkinson Abstract Utilizing the special advantages offered by the protracted maturation of neural circuits in chicken forebrain this study investigates the functional consequence of maturation using auditory evoked response potentials (AERPs) in behaving animals. Repeated measures AERP recordings were undertaken between weeks 1 and 8 posthatch. Quantitative analysis revealed a significant decrease in amplitude of the positive AERP component and a decrease in latency of the negative AERP component with maturation. AERPs were also utilized to investigate perturbed maturation via the induction of chemically induced hypothyroidism. Results from this study showed that the induction of late onset hypothyroidism produces measurable effects on the chicken AERP consistent with perturbation in maturation of neuronal circuits and synapses. This suggests that AERPs may be useful noninvasive functional measures of brain maturation that can be used to study the effects of endogenous or exogenous factors on brain maturation in the chicken. Since human brain also exhibits a protracted maturation period the availability of a well-characterized animal model for protracted brain maturation provides an opportunity to identify molecules, genes and environmental factors that are important in the regulation of maturation. The protracted maturation of neuronal circuits observed in chicken forebrain offers such a model. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 52: 24,34, 2010 [source] Accelerated nervous system development contributes to behavioral efficiency in the laboratory mouse: A behavioral review and theoretical proposalDEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2001Ian Q. Whishaw Abstract The emergence of the laboratory mouse as a favored species for genetic research has posed a number of problems for scientists interested in the reflection of genetic influences in mouse behavior. It is commonly thought that rat behavior, which has been studied more extensively than mouse behavior, could be easily generalized to mice. In this article, a number of categories of behavior displayed by the mouse (motor, spatial, defensive, social) are reviewed and contrasted with the same categories of behavior displayed by the rat. The comparison suggests that mouse behavior is simpler and more dependent upon elementary actions than the behavior of the rat. We suggest that the behavioral simplification in the mouse adapts it for a different ecological niche than that occupied by the rat. We propose that this simplification may be mediated by accelerated brain maturation during development. We further propose that this developmental acceleration in the mouse renders it less dependent upon complex social behavior and plastic nervous system changes associated with learning than the rat. This difference poses problems for the development of relevant methods of behavioral analysis and interpretation. Since the mouse's biological adaptations will be reflected in laboratory behavior, suggestions are made for behavioral approaches to the study and interpretation of mouse behavior. © 2001 John Wiley & Sons, Inc. Dev Psychobiol 39: 151,170, 2001 [source] Age-related changes in transient and oscillatory brain responses to auditory stimulation during early adolescenceDEVELOPMENTAL SCIENCE, Issue 2 2009Catherine Poulsen Maturational changes in the capacity to process quickly the temporal envelope of sound have been linked to language abilities in typically developing individuals. As part of a longitudinal study of brain maturation and cognitive development during adolescence, we employed dense-array EEG and spatiotemporal source analysis to characterize maturational changes in the timing of brain responses to temporal variations in sound. We found significant changes in the brain responses compared longitudinally at two time points in early adolescence, namely 10 years (65 subjects) and 11.5 years (60 of the 65 subjects), as well as large differences between adults, studied with the same protocol (Poulsen, Picton & Paus, 2007), and the children at 10 and 11.5 years of age. The transient auditory evoked potential to tone onset showed decreases in the latency of vertex and T-complex components, and a highly significant increase in the amplitude of the N1 wave with increasing age. The auditory steady state response to a 40-Hz frequency-modulated tone increased in amplitude with increasing age. The peak frequency of the envelope-following response to sweeps of amplitude-modulated white noise also increased significantly with increasing age. These results indicate persistent maturation of the cortical mechanisms for auditory processing from childhood into middle adulthood. [source] Cognitive outcome of status epilepticus in adultsEPILEPSIA, Issue 2007Christoph Helmstaedter Summary There is no doubt that structural morphological brain lesions and malformations in epilepsy represent major etiological factors for the cognitive impairments seen in this disease. The role of epileptic activity and seizures for cognition and cognitive development, however, is less easily determined. Epileptic dysfunction ranges from interictal and periictal activity over self-terminating seizures to non-convulsive and convulsive status epilepticus, which appear the most severe conditions along this continuum. The decisive question in this regard is as to whether cognitive impairments observed in the acute epileptic condition are reversible or not. Impairments from interictal or postictal epileptic dysfunction are reversible and may interfere at most with brain maturation and cognitive development in the young patient. Seizures and ictal dysfunction in contrast, even when reversible, can leave a permanent trace which extends the phase of postictal recovery. As for status epilepticus and subsequent cognitive decline it often remains open whether the epileptic condition itself or the underlying clinical condition is causative for the aftermath. While there is evidence for both possibilities, group data from neuropsychological cross sectional and longitudinal studies indicate that more severe mental impairments, which in turn indicate more severe clinical conditions, appear to be a risk factor for sustaining status epilepticus, rather than that status epilepticus causes the cognitive decline. Reviewing the literature the cognitive condition in patients with status epilepticus varies with the type of epilepsy, the etiology of epilepsy, severity of the status, and the age of the patient. [source] Organization of GABAA receptor ,-subunit clustering in the developing rat neocortex and hippocampusEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2004B. Hutcheon Abstract We compared the expression and co-expression of ,1, ,2, ,3, and ,5-subunit protein clusters of the ,-aminobutyric acid (GABA)A receptor in the neocortex and hippocampus of rat at postnatal days (PND) 5,10 and 30,40 in order to understand how inhibitory receptors reorganize during brain maturation. The size, intensity, density and pattern of co-localization of fluorescently tagged subunit clusters were determined in deconvolved digital images using a novel 2D cross-correlational analysis. The cross-correlation analysis allowed an unbiased identification of GABAA receptor subunit clusters based on staining intensity. Cluster size increased through development; only the ,2 clusters in dentate gyrus (DG) decreased in size. ,5-subunit cluster density either increased or decreased with maturation depending on the brain region. For the other subunits, the cluster density remained rather constant, with noted exceptions (increase in ,2 clusters in cortical layer 5 but a decrease of ,3 clusters in hilus). The co-localization of ,1-subunit with the others was unique and not correlated to overall changes in subunit abundance between developmental époques. So, although ,2-subunit expression went up in the DG, the clusters became less co-localized with ,1. In contrast, ,5-subunit clusters became more co-localized with ,1 as the ,5-subunit expression declined in cortex and CA1. The co-localization of ,3 with ,1 also became greater in layer 6. In the adult brain not all clustering was associated with synapses, as many ,-subunit clusters did not co-localize with synaptophysin. Overall, these data indicate that the regulation of GABAA receptor clustering is both synaptic and extrasynaptic, presumably reflecting complex cellular trafficking mechanisms. [source] Proton MRS of early post-natal mouse brain modifications in vivoNMR IN BIOMEDICINE, Issue 2 2006Pierre Larvaron Abstract NMR provides a non-invasive tool for the phenotypic characterisation of mouse models. The aim of the present study was to apply reliable in vivo MRS techniques for non-invasive investigations of brain development in normal and transgenic mice, by monitoring metabolite concentrations in different brain regions. The conditions of anaesthesia, immobilisation and respiratory monitoring were optimized to carry out in vivo MRS studies in young mice. All the experiments were performed in normal mice, at 9.4,T, applying a point-resolved spectroscopy (PRESS) sequence (TR,=,2000,ms; TE,=,130,ms). We obtained reproducible in vivo1H NMR spectra of wild-type mouse brains as early as post-natal day 5, which allowed us to follow brain maturation variations from post-natal days 5 to 21. The survival rate of animals was between 66 and 90% at post-natal days 5 and 21, respectively. Developmental changes of metabolite concentrations were measured in three brain regions: the thalamus, a region rich in cell bodies, the olfactory bulb, rich in fibre tracts actively myelinated during brain maturation, and the cerebellum. The voxel size varied from 2 to 8 µL according to the size of the brain structure analysed. The absolute concentrations of the total creatine, taurine, total choline, N -acetylaspartate and of the glutamate/glutamine pool were determined from 1H NMR spectra obtained in the different brain regions at post-natal day 5, 10, 15 and 21. Variations observed during brain development were in accordance with those previously reported in mice using ex vivo MRS studies, and also in rats and humans in vivo. Possibilities of longitudinal MRS analysis in maturing mice brains provide new perspectives to characterise better the tremendous number of transgenic mutant mice generated with the aim of decrypting the complexity of brain development and neurodegenerative diseases but also to follow the impact of environmental and therapeutic factors. Copyright © 2006 John Wiley & Sons, Ltd. [source] Absolute eigenvalue diffusion tensor analysis for human brain maturationNMR IN BIOMEDICINE, Issue 5 2003Yuji Suzuki Abstract The absolute eigenvalues of the diffusion tensor of white matter in sixteen normal subjects in two groups representing the early developmental stage (ages 1,10 years, n,=,8) and young adult stage (ages 18,34 years, n,=,8) were assessed using a high-field (3.0,T) magnetic resonance (MR) system. All three eigenvalues, including the largest eigenvalue, decreased significantly with brain maturation. The rate of the decline in the two small eigenvalues was, however, much higher than that of the largest eigenvalue, resulting in an actual increase in fractional anisotropy, a commonly measured relative index. The data demonstrate that an increase in anisotropy associated with brain maturation represents a significant decline in the small eigenvalue components, rather than an increase in the largest eigenvalue. The observed pattern of eigenvalue changes is best explained by the simultaneous occurrence of two of several independent phenomena within the axonal microenvironment during the myelination process, namely, (1) decline in unrestricted water content in extra-axonal space, and (2) increase in apparent diffusivity within the axon. Copyright © 2003 John Wiley & Sons, Ltd. [source] Assessment of cortical gyrus and sulcus formation using magnetic resonance images in small-for-gestational-age fetusesPRENATAL DIAGNOSIS, Issue 5 2004Seiji Abe Abstract Objectives The purpose was to compare the development of gyrus and sulcus formation (GSF), an indicator of brain maturation, in small-for-gestational-age (SGA) fetuses using magnetic resonance (MR) imaging, with those of appropriate-for-gestational-age (AGA) fetuses. Methods The 160 infants with a normal neurological outcome were divided into two groups on the basis of their body weight at delivery; 37 SGA infants (Group SGA) and 123 AGA infants (Group AGA). Fetal MR images, which were obtained from 28 to 39 gestational weeks in Group SGA and from 18 to 39 gestational weeks in Group AGA, were classified into the 8 stages of development for GSF established by Abe et al. (2003), and comparison was made between the two groups retrospectively in their neurological development in relation to gestational age. Results In Group SGA, images were classified into stages 3 to 8 (P < 0.001). The gestational age of the cases determined for each stage between Groups SGA and AGA did not differ significantly, with respect to the development of GSF, despite differences in fetal estimated body weights. Conclusion In SGA fetuses, evaluation of fetal GSF using MR images during the third trimester may be useful for predicting neurological prognoses postpartum. Copyright © 2004 John Wiley & Sons, Ltd. [source] Developmental origins of disruptive behaviour problems: the ,original sin' hypothesis, epigenetics and their consequences for preventionTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 4 2010Richard E. Tremblay This paper reviews publications on developmental trajectories of disruptive behaviour (DB) problems (aggression, opposition-defiance, rule breaking, and stealing-vandalism) over the past decade. Prior to these studies two theoretical models had strongly influenced research on DB: social learning and disease onset. According to these developmental perspectives, children learn DB from their environment and onset of the disease is triggered by accumulated exposition to disruptive models in the environment, including the media. Most of the evidence came from studies of school age children and adolescents. Longitudinal studies tracing developmental trajectories of DB from early childhood onwards suggest an inversed developmental process. DB are universal during early childhood. With age, children learn socially acceptable behaviours from interactions with their environment. A ,disease' status is given to children who fail to learn the socially acceptable behaviours. The mechanisms that lead to deficits in using socially accepted behaviours are strongly intergenerational, based on complex genetic and environmental contributions, including epigenetic mechanisms. Prevention of these deficits requires early, intensive and long-term support to parents and child. Newly discovered epigenetic mechanisms suggest that intensive perinatal interventions will have impacts on numerous aspects of physical and mental health, including DB. This review also concludes that: a) subtypes of disruptive behaviours should not be aggregated because they have different developmental trajectories and require specific corrective interventions; b) the overt,covert and destructive,nondestructive dimensions appear the most useful to create DB subtypes; c) overt DB onset before covert DB because the latter require more brain maturation; d) DB subtype taxonomies are more useful for clinicians than developmental taxonomies because the latter are post mortem diagnoses and clinicians' retrospective information is unreliable; e) we need large-scale collaborative preventive experimental interventions starting during early pregnancy to advance knowledge on causes and prevention of DB problems. [source] Infant Intersubjectivity: Research, Theory, and Clinical ApplicationsTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 1 2001Colwyn Trevarthen We review research evidence on the emergence and development of active " self-and-other " awareness in infancy, and examine the importance of its motives and emotions to mental health practice with children. This relates to how communication begins and develops in infancy, how it influences the individual subject's movement, perception, and learning, and how the infant's biologically grounded self-regulation of internal state and self-conscious purposefulness is sustained through active engagement with sympathetic others. Mutual selfother- consciousness is found to play the lead role in developing a child's cooperative intelligence for cultural learning and language. A variety of preconceptions have animated rival research traditions investigating infant communication and cognition. We distinguish the concept of " intersubjectivity ", and outline the history of its use in developmental research. The transforming body and brain of ahumanindividual grows in active engagement with an environment of human factors-organic at first, then psychological or inter-mental. Adaptive, human-responsive processes are generated first by interneuronal activity within the developing brain as formation of the human embryo is regulated in a support-system of maternal tissues. Neural structures are further elaborated with the benefit of intra-uterine stimuli in the foetus, then supported in the rapidly growing forebrain and cerebellum of the young child by experience of the intuitive responses of parents and other human companions. We focus particularly on intrinsic patterns and processes in pre-natal and post-natal brain maturation that anticipate psychosocial support in infancy. The operation of an intrinsic motive formation (IMF) that developed in the core of the brain before birth is evident in the tightly integrated intermodal sensory-motor coordination of a newborn infant's orienting to stimuli and preferential learning of human signals, by the temporal coherence and intrinsic rhythms of infant behaviour, especially in communication, and neonates' extraordinary capacities for reactive and evocative imitation. The correct functioning of this integrated neural motivating system is found to be essential to the development of both the infant's purposeful consciousness and his or her ability to cooperate with other persons' actions and interests, and to learn from them. The relevance of infants' inherent intersubjectivity to major child mental health issues is highlighted by examining selected areas of clinical concern. We review recent findings on postnatal depression, prematurity, autism, ADHD, specific language impairments, and central auditory processing deficits, and comment on the effcacy of interventions that aim to support intrinsic motives for intersubjective communication when these are not developing normally. [source] Glutathione peroxidase activity modulates recovery in the injured immature brain,ANNALS OF NEUROLOGY, Issue 5 2009Kyoko Tsuru-Aoyagi MD Objective Mice subjected to traumatic brain injury at postnatal day 21 show emerging cognitive deficits that coincide with hippocampal neuronal loss. Here we consider glutathione peroxidase (GPx) activity as a determinant of recovery in the injured immature brain. Methods Wild-type and transgenic (GPxTg) mice overexpressing GPx were subjected to traumatic brain injury or sham surgery at postnatal day 21. Animals were killed acutely (3 or 24 hours after injury) to assess oxidative stress and cell injury in the hippocampus or 4 months after injury after behavioral assessments. Results In the acutely injured brains, a reduction in oxidative stress markers including nitrotyrosine was seen in the injured GPxTg group relative to wild-type control mice. In contrast, cell injury, with marked vulnerability in the dentate gyrus, was apparent despite no differences between genotypes. Magnetic resonance imaging demonstrated an emerging cortical lesion during brain maturation that was also indistinguishable between injured genotypes. Stereological analyses of cortical volumes likewise confirmed no genotypic differences between injured groups. However, behavioral tests beginning 3 months after injury demonstrated improved spatial memory learning in the GPxTg group. Moreover, stereological analysis within hippocampal subregions demonstrated a significantly greater number of neurons within the dentate of the GPx group. Interpretation Our results implicate GPx in recovery of spatial memory after traumatic brain injury. This recovery may be attributed, in part, to a reduction in early oxidative stress and selective, long-term sparing of neurons in the dentate. Ann Neurol 2009;65:540,549 [source] Glycosaminoglycan in cerebrum, cerebellum and brainstem of young sheep brain with particular reference to compositional and structural variations of chondroitin,dermatan sulfate and hyaluronanBIOMEDICAL CHROMATOGRAPHY, Issue 9 2008Virginia Kilia Abstract Recent advances in the structural biology of chondroitin sulfate chains have suggested important biological functions in the development of the brain. Several studies have demonstrated that the composition of chondroitin sulfate chains changes with aging and normal brain maturation. In this study, we determined the concentration of all glycosaminoglycan types, i.e. chondroitin sulfate, dermatan sulfate, keratan sulfate, heparan sulfate, hyaluronan and chondroitin in cerebrum, cerebellum and brainstem of young sheep brain. In all cases, chondroitin sulfate was the predominant glycosaminoglycan type, comprising about 54,58% of total glycosaminoglycans, with hyaluronan being present also in significant amounts of about 19,28%. Of particular interest was the increased presence of the disulfated disaccharides and dermatan sulfate in cerebellum and brainstem, respectively, as well as the detectable and measurable occurrence of chondroitin in young sheep brain. Among the three brain areas, cerebrum was found to be significantly richer in chondroitin sulfate and hyaluronan, two major extracellular matrix components. These findings imply that the extracellular matrix of the cerebrum is different from those of cerebellum and brainstem, and probably this fact is related to the particular histological and functional characteristics of each anatomic area of the brain. Copyright © 2008 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||