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"Adolescence"
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Age-related changes in the structure and function of prefrontal cortexaamygdala circuitry in children and adolescents: A multi-modal imaging approach
The uncinate fasciculus is a major white matter tract that provides a crucial link between areas of the human brain that underlie emotion processing and regulation. Specifically, the uncinate fasciculus is the major direct fiber tract that connects the prefrontal cortex and the amygdala. The aim of the present study was to use a multi-modal imaging approach in order to simultaneously examine the relation between structural connectivity of the uncinate fasciculus and functional activation of the amygdala in a youth sample (children and adolescents). Participants were 9 to 19 years old and underwent diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI). Results indicate that greater structural connectivity of the uncinate fasciculus predicts reduced amygdala activation to sad and happy faces. This effect is moderated by age, with younger participants exhibiting a stronger relation. Further, decreased amygdala activation to sad faces predicts lower internalizing symptoms. These results provide important insights into brain structureafunction relationships during adolescence, and suggest that greater structural connectivity of the uncinate fasciculus may facilitate regulation of the amygdala, particularly during early adolescence. These findings also have implications for understanding the relation between brain structure, function, and the development of emotion regulation difficulties, such as internalizing symptoms.
Journal Article
Randomized trial using ultrasound to assess intramuscular vaccination at a 60 degree or 90 degree needle angle
Objective: Globally, recommendations differ on the ideal angle of needle insertion to ensure vaccinate deposition in muscle for optimal safety and immunogenicity. This study aimed to compare the level of vaccinate deposition during vaccination, using two different needle angles (60 degree and 90 degree ), in young children, adolescents and adults. Methods: In this randomized cross-over study, two doses of a licensed hepatitis vaccine, were administered to study participants, at a 60 degree or 90 degree angle using a fixed template. Ultrasonography was performed with a Philips iu22 ultrasound system. Real time clips and hard copies of images were recorded showing the injection and level of deposition of the vaccinate. Reactogenicity at the site of administration was assessed by participants/parents. Results: Nineteen participants were enrolled including children, adolescents and adults. Of the total 38 injections performed, 29 (76%) were confirmed by ultrasound as intramuscular (IM), 3 (8%) as not IM, and 6 (16%) unknown. For vaccinations visualised and administered at 60 degree , 87% (13/15) were intramuscular vs 94.1% (16/17) for those administered at 90 degree . A body mass index (BMI) less than or equal to 25 was associated with a higher likelihood of IM injection compared to BMI>25 (p = 0.038). There were no differences in reactogenicity for either 60 degree or 90 degree angle of administration. Conclusion: For the majority of vaccinees, a 60-90 degree angle of vaccine administration is appropriate for IM deposition of vaccinate. The likelihood of intramuscular deposition is reduced for individuals with a BMI>25. The increasing rates of obesity globally highlight the importance of tailoring vaccination procedures accordingly.
Journal Article
Negotiating adolescence in times of social change
This volume considers the processes through which societal changes exert an impact on the course of adolescent development.
Book
5-HTTLPRaenvironment interplay and its effects on neural reactivity in adolescents
It is not known how 5-HTTLPR genotype A childhood adversity (CA) interactions that are associated with an increased risk for affective disorders in population studies operate at the neural systems level. We hypothesized that healthy adolescents at increased genetic and environmental risk for developing mood disorders (depression and anxiety) would demonstrate increased amygdala reactivity to emotional stimuli compared to those with only one such risk factor or those with none. Participants (n = 67) were classified into one of 4 groups dependent on being homozygous for the long or short alleles within the serotonin-transporter-linked polymorphic region (5-HTTLPR) of the SLC6A4 gene and exposure to CA in the first 11 years of life (present or absent). A functional magnetic resonance imaging investigation was undertaken which involved viewing emotionally-salient face stimuli. In addition, we assessed the role of other variables hypothesized to influence amygdala reactivity, namely recent negative life-events (RNLE) assessed at ages 14 and 17, current anxiety symptoms and psychiatric history. We replicated prior findings demonstrating moderation by gene variants in 5-HTTLPR, but found no support for an effect of CA on amygdala reactivity. We also found a significant effect of RNLE aged 17 with amygdala reactivity demonstrating additive, but not interactive effects with 5-HTTLPR. A whole-brain analysis found a 5-HTTLPR A CA interaction in the lingual gyrus whereby CA appears to differentially modify neural reactivity depending on genotype. These results demonstrate that two different forms of environmental adversities interplay with 5-HTTLPR and thereby differentially impact amygdala and cortical reactivity.
Journal Article
Reinventing Childhood After World War II
In the Western world, the modern view of childhood as a space protected from broader adult society first became a dominant social vision during the nineteenth century. Many of the West's sharpest portrayals of children in literature and the arts emerged at that time in both Europe and the United States and continue to organize our perceptions and sensibilities to this day. But that childhood is now being recreated. Many social and political developments since the end of the World War II have fundamentally altered the lives children lead and are now beginning to transform conceptions of childhood.Reinventing Childhood After World War IIbrings together seven prominent historians of modern childhood to identify precisely what has changed in children's lives and why. Topics range from youth culture to children's rights; from changing definitions of age to nontraditional families; from parenting styles to how American experiences compare with those of the rest of the Western world. Taken together, the essays argue that children's experiences have changed in such dramatic and important ways since 1945 that parents, other adults, and girls and boys themselves have had to reinvent almost every aspect of childhood.Reinventing Childhood After World War IIpresents a striking interpretation of the nature and status of childhood that will be essential to students and scholars of childhood, as well as policy makers, educators, parents, and all those concerned with the lives of children in the world today.
eBook
Catechol-o-methyl transferase (COMT) val super(158met polymorphism and adolescent cortical development in patients with childhood-onset schizophrenia, their non-psychotic siblings, and healthy controls)
Non-psychotic individuals at increased risk for schizophrenia show alterations in fronto-striatal dopamine signaling and cortical gray matter maturation reminiscent of those seen in schizophrenia. It remains unclear however if variations in dopamine signaling influence rates of structural cortical maturation in typically developing individuals, and whether such influences are disrupted in patients with schizophrenia and their non-psychotic siblings. We sought to address these issues by relating a functional Val -- Met polymorphism within the gene encoding catechol-o-methyltransferase (COMT) - a key enzymatic regulator of cortical dopamine levels - to longitudinal structural neuroimaging measures of cortical gray matter thickness. We included a total of 792 magnetic resonance imaging brain scans, acquired between ages 9 and 22 years from patients with childhood-onset schizophrenia (COS), their non-psychotic full siblings, and matched healthy controls. Whereas greater Val allele dose (which confers enhanced dopamine catabolism and is proposed to aggravate cortical deficits in schizophrenia) accelerated adolescent cortical thinning in both schizophrenia probands and their siblings, it attenuated cortical thinning in healthy controls. This similarity between COS patients and their siblings was accompanied by differences between the two groups in the timing and spatial distribution of disrupted COMT influences on cortical maturation. Consequently, whereas greater Val \"dose\" conferred persistent dorsolateral prefrontal cortical deficits amongst affected probands by adulthood, cortical thickness differences associated with varying Val dose in non-psychotic siblings resolved over the age-range studied. These findings suggest that cortical abnormalities in pedigrees affected by schizophrenia may be contributed to by a disruption of dopaminergic infleunces on cortical maturation.
Journal Article