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The hippocampus is necessary for declarative (relational) memory, and the ability to form hippocampal‐dependent memories develops through late adolescence. This developmental trajectory of hippocampal‐dependent memory could reflect maturation of intrinsic functional brain networks, but resting‐state functional connectivity (rs‐FC) of the human hippocampus is not well‐characterized for periadolescent children. Measuring hippocampal rs‐FC in periadolescence would thus fill a gap, and testing covariance of hippocampal rs‐FC with age and memory could inform theories of cognitive development. Here, we studied hippocampal rs‐FC in a cross‐sectional sample of healthy children (N = 96; 59 F; age 9–15 years) using a seed‐based approach, and linked these data with NIH Toolbox measures, the Picture‐Sequence Memory Test (PSMT) and the List Sorting Working Memory Test (LSWMT). The PSMT was expected to rely more on hippocampal‐dependent memory than the LSWMT. We observed hippocampal rs‐FC with an extensive brain network including temporal, parietal, and frontal regions. This pattern was consistent with prior work measuring hippocampal rs‐FC in younger and older samples. We also observed novel, regionally specific variation in hippocampal rs‐FC with age and hippocampal‐dependent memory but not working memory. Evidence consistent with these findings was observed in a second, validation dataset of similar‐age healthy children drawn from the Philadelphia Neurodevelopment Cohort. Further, a cross‐dataset analysis suggested generalizable properties of hippocampal rs‐FC and covariance with age and memory. Our findings connect prior work by describing hippocampal rs‐FC and covariance with age and memory in typically developing periadolescent children, and our observations suggest a developmental trajectory for brain networks that support hippocampal‐dependent memory., The hippocampus is necessary for normal declarative (relational) memory, and the ability to form hippocampal‐dependent memories continues to develop through late adolescence. We studied the intrinsic (resting) functional connectivity of the hippocampus in two cross‐sectional samples (discovery and validation) of healthy periadolescent using a seed‐based approach, and measured the covariance of hippocampal functional connectivity with age and memory performance. In addition to predicted patterns of functional connectivity for hippocampus, we also observed novel, region‐specific variation in hippocampal functional connectivity with age and hippocampal‐dependent memory.

Contains fulltext : 219496.pdf (Publisher’s version ) (Closed access) DNA methylation is the most studied modification in human population epigenetics. Its information content can be explored in 2 principal ways - epigenome-wide association studies and epigenetic age. The latter likely reflects cellular/biological age and works with impressive accuracy across most tissues. In adults, it associates with various environments and health. However, current epigenetic clocks are not very accurate in the pediatric age range perhaps because DNA methylation changes much faster in children. Addressing this crucial gap, we created a precise tool to estimate DNA methylation age specific to pediatric buccal epithelial cells. This tool has the potential to become the standard reference for epigenetic studies broadly relevant to child development across the spectrum from health to disease.The development of biological markers of aging has primarily focused on adult samples. Epigenetic clocks are a promising tool for measuring biological age that show impressive accuracy across most tissues and age ranges. In adults, deviations from the DNA methylation (DNAm) age prediction are correlated with several age-related phenotypes, such as mortality and frailty. In children, however, fewer such associations have been made, possibly because DNAm changes are more dynamic in pediatric populations as compared to adults. To address this gap, we aimed to develop a highly accurate, noninvasive, biological measure of age specific to pediatric samples using buccal epithelial cell DNAm. We gathered 1,721 genome-wide DNAm profiles from 11 different cohorts of typically developing individuals aged 0 to 20 y old. Elastic net penalized regression was used to select 94 CpG sites from a training dataset (n = 1,032), with performance assessed in a separate test dataset (n = 689). DNAm at these 94 CpG sites was highly predictive of age in the test cohort (median absolute error = 0.35 y). The Pediatric-Buccal-Epigenetic (PedBE) clock was characterized in additional cohorts, showcasing the accuracy in longitudinal data, the performance in nonbuccal tissues and adult age ranges, and the association with obstetric outcomes. The PedBE tool for measuring biological age in children might help in understanding the environmental and contextual factors that shape the DNA methylome during child development, and how it, in turn, might relate to child health and disease. 7 p.

At rest, human brain functional networks display striking modular architecture in which coherent clusters of brain regions are activated. The modular account of brain function is pervasive, reliable, and reproducible. Yet, a complementary perspective posits a core–periphery or rich-club account of brain function, where hubs are densely interconnected with one another, allowing for integrative processing. Unifying these two perspectives has remained difficult due to the fact that the methodological tools to identify modules are entirely distinct from the methodological tools to identify core–periphery structure. Here, we leverage a recently-developed model-based approach—the weighted stochastic block model—that simultaneously uncovers modular and core–periphery structure, and we apply it to functional magnetic resonance imaging data acquired at rest in 872 youth of the Philadelphia Neurodevelopmental Cohort. We demonstrate that functional brain networks display rich mesoscale organization beyond that sought by modularity maximization techniques. Moreover, we show that this mesoscale organization changes appreciably over the course of neurodevelopment, and that individual differences in this organization predict individual differences in cognition more accurately than module organization alone. Broadly, our study provides a unified assessment of modular and core–periphery structure in functional brain networks, offering novel insights into their development and implications for behavior.

Cognitive functions mature at different points in time between birth and adulthood. Of these functions, visuospatial skills, such as spatial memory and part-to-whole organization, have often been tested in children and adults but have been less frequently evaluated during adolescence. We studied visuospatial memory and ability during this critical developmental period, as well as the correlation between these abilities, in a large group of 330 participants (aged 11 to 20 years, 55% male). To assess visuospatial memory, the participants were asked to memorize and reproduce sequences of random locations within a grid using a computer. Visuospatial ability was tested using a variation of the Design Organization Test (DOT). In this paper-and-pencil test, the participants had one minute to reproduce as many visual patterns as possible using a numerical code. On the memory task, compared with younger participants, older participants correctly reproduced more locations overall and longer sequences of locations, made fewer mistakes and needed less time to reproduce the sequences. In the visuospatial ability task, the number of correctly reproduced patterns increased with age. We show that both visuospatial memory and ability improve significantly throughout adolescence and that performance on both tasks is significantly correlated.

Learning from feedback is an important aspect of executive functioning that shows profound improvements during childhood and adolescence. This is accompanied by neural changes in the feedback-learning network, which includes pre-supplementary motor area (pre- SMA)/anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), superior parietal cortex (SPC), and the basal ganglia. However, there can be considerable differences within age ranges in performance that are ascribed to differences in strategy use. This is problematic for traditional approaches of analyzing developmental data, in which age groups are assumed to be homogenous in strategy use. In this study, we used latent variable models to investigate if underlying strategy groups could be detected for a feedback-learning task and whether there were differences in neural activation patterns between strategies. In a sample of 268 participants between ages 8 to 25 years, we observed four underlying strategy groups, which were cut across age groups and varied in the optimality of executive functioning. These strategy groups also differed in neural activity during learning; especially the most optimal performing group showed more activity in DLPFC, SPC and pre-SMA/ACC compared to the other groups. However, age differences remained an important contributor to neural activation, even when correcting for strategy. These findings contribute to the debate of age versus performance predictors of neural development, and highlight the importance of studying individual differences in strategy use when studying development.

Background: The modified Balance Error Scoring System (mBESS) and Y-Balance Test are common clinical measurements of postural control, but little is known about the effect of age on performance of these tasks. The purpose of this study was to examine how healthy child and adolescent athletes perform on 2 common clinical measurements of postural control. Hypothesis: Younger athletes would demonstrate poorer postural control compared with older athletes. Study Design: Cross-sectional study. Level of Evidence: Level 3. Methods: Three hundred eighty-nine athletes between the ages of 10 and 18 years underwent an evaluation of postural control. Each participant completed the mBESS in the double-leg, single-leg, and tandem stances as well as the Y-Balance Test. Postural stability data were analyzed between age groups (10-12, 13-15, and 16-18 years) using univariate analyses of covariance. Results: The youngest athletes (10-12 years) had a greater mean number of errors in the single-leg stance of the mBESS than the 13- to 15-year-old and 16- to 18-year-old athletes (3.8, 3, and 2.5 errors, respectively; P < 0.01). They also had greater right to left asymmetry compared with the 16- to 18-year-old athletes on the Y-Balance Test in the posterolateral (6.8 and 3.8 cm, respectively; P = 0.006) and posteromedial (5.3 and 3.6 cm, respectively; P = 0.014) directions of movement. Conclusion: Athletes between the ages of 10 and 12 years performed worse on the single-leg stance of the mBESS and demonstrated more asymmetry on the Y-Balance Test in the posterolateral and posteromedial directions compared with older athletes. Clinical Relevance: In the absence of a baseline balance test for athletes younger than the age of 13 years, caution should be used in interpreting postural stability assessments, as age may be a modifying factor in performance.

This study investigated which strategies children aged 5-15 years (N = 408) employ while performing a multitrial free recall test of semantically unrelated words. Serial clustering (i.e., a relatively passive strategy) is an index of the sequential consistency of recall order. Subjective clustering (i.e., a more active strategy) is based on similar word groupings in successive trials. Previously, Meijs et al. (2009) found that the level of (serial and subjective) clustering increases with age. At all ages, the level of serial clustering correlates positively with the ability to recall information on VLT trials. However, subjective clustering is more predictive of VLT performance than serial clustering after ≥ 3 trials, but only in children aged 8+. Knowledge on how children organize words (based on, for example, sound or meaning) and how this relates to developmental stage is still lacking. This study revealed that the level of subjective clustering is primarily determined by the position of words in a VLT list. More specifically, primacy (i.e., recall of words 1-3 of the VLT list-whether recalled in the same order or reversed) and recency (i.e., recall of words 14-15) effects primarily determine level subjective organization over successive trials. Thus, older children still organize words based on the serial position of the VLT list and are much less likely to organize them based on any other feature of the words, for example, sound or meaning. This indicates that the most important information to be learned needs to be presented first or last, even in older children and even with repeated presentations. © 2013 Taylor & Francis Group, LLC.

Highlights • We use a ‘virtual maze’ to elicit the reward positivity in 8–23 year olds. • Reward positivity amplitude is comparable across children, adolescents and adults. • Children have longer latencies for P200, N200 and P300 ERP components. • We propose that dopamine reinforcement signals develop early to guide behavior., Children and adolescents learn to regulate their behavior by utilizing feedback from the environment but exactly how this ability develops remains unclear. To investigate this question, we recorded the event-related brain potential (ERP) from children (8–13 years), adolescents (14–17 years) and young adults (18–23 years) while they navigated a “virtual maze” in pursuit of monetary rewards. The amplitude of the reward positivity, an ERP component elicited by feedback stimuli, was evaluated for each age group. A current theory suggests the reward positivity is produced by the impact of reinforcement learning signals carried by the midbrain dopamine system on anterior cingulate cortex, which utilizes the signals to learn and execute extended behaviors. We found that the three groups produced a reward positivity of comparable size despite relatively longer ERP component latencies for the children, suggesting that the reward processing system reaches maturity early in development. We propose that early development of the midbrain dopamine system facilitates the development of extended goal-directed behaviors in anterior cingulate cortex.

International audience; BACKGROUND:The purpose of this investigation was to evaluate an association between duration of exclusive breastfeeding and structure of cortical regions implicated in general intelligence.METHODS:We studied adolescents (n = 571; aged 12-18 years) participating in the Saguenay Youth Study; half of the participants were exposed to maternal cigarette smoking during pregnancy. Hierarchical linear modelling was used to assess whether breastfeeding is an important predictor of cortical thickness when other predictors, such as age, sex, parental education and exposure to maternal smoking during pregnancy, are also considered. Target cortical regions were identified using a meta-analysis of functional neuroimaging studies of cognitive abilities relevant for general intelligence.RESULTS:We found that duration of exclusive breastfeeding was associated with cortical thickness in the superior and inferior parietal lobules (t = 2.31, P = 0.02). We also replicated the association between breastfeeding and general intelligence (t = 2.69, P = 0.008).CONCLUSION:In this study, we showed that breastfeeding is associated with variations in the thickness of the parietal cortex in a community-based sample of adolescents. We also found association of breastfeeding duration with full scale and performance IQ, as observed previously.