Ablation of placental REST deregulates fetal brain metabolism and impacts gene expression of the offspring brain at the postnatal and adult stages

In this study, the transcriptional repressor REST (Repressor Element 1 Silencing Transcription factor) was ablated in the mouse placenta to investigate molecular and cellular impacts on the offspring brain at different life stages. Ablation of placental REST deregulated several brain metabolites, including glucose and lactate that fuel brain energy, vitamin C (ascorbic acid) that functions in the epigenetic programming of the brain during postnatal development, and glutamate and creatine that help the brain to respond to stress conditions during adult life. Bulk RNA-seq analysis showed that a lack of placental REST persistently altered multiple transport genes, including those related to oxygen transportation in the offspring brain. While metabolic genes were impacted in the postnatal brain, different stress response genes were activated in the adult brain. DNA methylation was also impacted in the adult brain due to the loss of placental REST, but in a sex-biased manner. Single-nuclei RNA-seq analysis showed that specific cell types of the brain, particularly those of the choroid plexus and ependyma, which play critical roles in producing cerebrospinal fluid and maintaining metabolic homeostasis, were significantly impacted due to the loss of placental REST. These cells showed significant differential expression of genes associated with the metabotropic (G coupled protein) and ionotropic (ligand-gated ion channel) glutamate receptors, suggesting an impact of ablation of placental REST on the glutamatergic signaling of the offspring brain. The study expands our understanding of placental influences on the offspring brain.

Biomarkers of Affective Dysregulation Associated with In Utero Exposure to EtOH

INTRODUCTION

Children with fetal alcohol spectrum disorders (FASD) exhibit behavioral and affective dysregulation, including hyperactivity and depression. The mechanisms are not known, but they could conceivably be due to postnatal social or environmental factors. However, we postulate that, more likely, the affective dysregulation is associated with the effects of EtOH exposure on the development of fetal serotonergic (5-HT) and/or dopaminergic (DA) pathways, i.e., pathways that in postnatal life are believed to regulate mood. Many women who use alcohol (ethanol, EtOH) during pregnancy suffer from depression and take selective serotonin reuptake inhibitors (SSRIs), which might influence these monoaminergic pathways in the fetus. Alternatively, monoaminergic pathway abnormalities might reflect a direct effect of EtOH on the fetal brain. To distinguish between these possibilities, we measured their expressions in fetal brains and in fetal brain-derived exosomes (FB-Es) isolated from the mothers' blood. We hypothesized that maternal use of EtOH and/or SSRIs during pregnancy would be associated with impaired fetal neural development, detectable as abnormal levels of monoaminergic and apoptotic biomarkers in FB-Es.

METHODS

Fetal brain tissues and maternal blood were collected at 9-23 weeks of pregnancy. EtOH groups were compared with unexposed controls matched for gestational age (GA). The expression of 84 genes associated with the DA and 5-HT pathways was analyzed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) on microarrays. FB-Es also were assayed for serotonin transporter protein (SERT) and brain-derived neurotrophic factor (BDNF) by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Six EtOH-exposed human fetal brain samples were compared to SSRI- or polydrug-exposed samples and to unexposed controls. EtOH exposure was associated with significant upregulation of DA receptor D3 and 5-HT receptor HTR2C, while HTR3A was downregulated. Monoamine oxidase A (MAOA), MAOB, the serine/threonine kinase AKT3, and caspase-3 were upregulated, while mitogen-activated protein kinase 1 (MAPK1) and AKT2 were downregulated. ETOH was associated with significant upregulation of the DA transporter gene, while SERT was downregulated. There were significant correlations between EtOH exposure and (a) caspase-3 activation, (b) reduced SERT protein levels, and (c) reduced BDNF levels. SSRI exposure independently increased caspase-3 activity and downregulated SERT and BDNF. Early exposure to EtOH and SSRI together was associated synergistically with a significant upregulation of caspase-3 and a significant downregulation of SERT and BDNF. Reduced SERT and BDNF levels were strongly correlated with a reduction in eye diameter, a somatic manifestation of FASD.

CONCLUSIONS

Maternal use of EtOH and SSRI during pregnancy each was associated with changes in fetal brain monoamine pathways, consistent with potential mechanisms for the affective dysregulation associated with FASD.

β-Adrenergic Signaling Promotes Morphological Maturation of Astrocytes in Female Mice

Astrocytes play essential roles in the developing nervous system, including supporting synapse function. These astrocyte support functions emerge coincident with brain maturation and may be tailored in a region-specific manner. For example, gray matter astrocytes have elaborate synapse-associated processes and are morphologically and molecularly distinct from white matter astrocytes. This raises the question of whether there are unique environmental cues that promote gray matter astrocyte identity and synaptogenic function. We previously identified adrenergic receptors as preferentially enriched in developing gray versus white matter astrocytes, suggesting that noradrenergic signaling could be a cue that promotes the functional maturation of gray matter astrocytes. We first characterized noradrenergic projections during postnatal brain development in mouse and human, finding that process density was higher in the gray matter and increased concurrently with astrocyte maturation. RNA sequencing revealed that astrocytes in both species expressed α- and β-adrenergic receptors. We found that stimulation of β-adrenergic receptors increased primary branching of rodent astrocytes in vitro Conversely, astrocyte-conditional knockout of the β1-adrenergic receptor reduced the size of gray matter astrocytes and led to dysregulated sensorimotor integration in female mice. These studies suggest that adrenergic signaling to developing astrocytes impacts their morphology and has implications for adult behavior, particularly in female animals. More broadly, they demonstrate a mechanism through which environmental cues impact astrocyte development. Given the key roles of norepinephrine in brain states, such as arousal, stress, and learning, these findings could prompt further inquiry into how developmental stressors impact astrocyte development and adult brain function.SIGNIFICANCE STATEMENT This study demonstrates a role for noradrenergic signaling in the development of gray matter astrocytes. We provide new evidence that the β1-adrenergic receptor is robustly expressed by both mouse and human astrocytes, and that conditional KO of the β1-adrenergic receptor from female mouse astrocytes impairs gray matter astrocyte maturation. Moreover, female conditional KO mice exhibit behavioral deficits in two paradigms that test sensorimotor function. Given the emerging interest in moving beyond RNA sequencing to probe specific pathways that underlie astrocyte heterogeneity, this study provides a foundation for future investigation into the effect of noradrenergic signaling on astrocyte functions in conditions where noradrenergic signaling is altered, such as stress, arousal, and learning.

Neuroimaging and Neurodevelopmental Outcomes Among Individuals With Complex Congenital Heart Disease: JACC State-of-the-Art Review

Although neuroimaging advances have deepened our understanding of brain health in individuals with congenital heart disease (CHD), it is less clear how neuroimaging findings relate to neurodevelopmental and mental health outcomes across the lifespan. We systematically synthesized and critically evaluated evidence on associations between neuroimaging and neurodevelopmental, neurocognitive, psychiatric, or behavioral outcomes among individuals with transposition of great arteries or single-ventricle CHD (Protocol CRD42021229617). Six databases were searched and 45 papers from 25 unique studies were identified. Structural brain injury was generally linked to poorer neurodevelopment in infancy. Brain volumes and microstructural and functional brain changes appear linked to neurocognitive outcomes, including deficits in attention, learning, memory, and executive function in children and adolescents. Fetal neuroimaging studies were limited. Four papers investigated psychiatric outcomes; none found associations with neuroimaging. Multicenter, longitudinal studies incorporating functional neuroimaging and mental health outcomes are much-needed to inform early neuroprotective and therapeutic strategies in CHD.

Sub-voxel quantitative susceptibility mapping for assessing whole-brain magnetic susceptibility from ages 4 to 80

The evolution of magnetic susceptibility of the brain is mainly determined by myelin in white matter (WM) and iron deposition in deep gray matter (DGM). However, existing imaging techniques have limited abilities to simultaneously quantify the myelination and iron deposition within a voxel throughout brain development and aging. For instance, the temporal trajectories of iron in the brain WM and myelination in DGM have not been investigated during the aging process. This study aimed to map the age-related iron and myelin changes in the whole brain, encompassing myelin in DGM and iron deposition in WM, using a novel sub-voxel quantitative susceptibility mapping (QSM) method. To achieve this, a cohort of 494 healthy adults (18-80 years old) was studied. The sub-voxel QSM method was employed to obtain the paramagnetic and diamagnetic susceptibility based on the approximatedR 2 ' map from acquiredR 2 * map. The linear relationship betweenR 2 * andR 2 ' maps was established from the regression coefficients on a small cohort data acquired with both 3D gradient recalled echo data andR 2 mapping. Large cohort sub-voxel susceptibility maps were used to create longitudinal and age-specific atlases via group-wise registration. To explore the differential developmental trajectories in the DGM and WM, we employed nonlinear models including exponential and Poisson functions, along with generalized additive models. The constructed atlases reveal the iron accumulation in the posterior part of the putamen and the gradual myelination process in the globus pallidus with aging. Interestingly, the developmental trajectories show that the rate of myelination differs among various DGM regions. Furthermore, the process of myelin synthesis is paralleled by an associated pattern of iron accumulation in the primary WM fiber bundles. In summary, our study offers significant insights into the distinctive developmental trajectories of iron in the brain's WM and myelination/demyelination in the DGM in vivo. These findings highlight the potential of using sub-voxel QSM to uncover new perspectives in neuroscience and improve our understanding of whole-brain myelination and iron deposit processes across the lifespan.

Early-in-life isoflurane exposure alters resting-state functional connectivity in juvenile non-human primates

BACKGROUND

Clinical studies suggest that anaesthesia exposure early in life affects neurobehavioural development. We designed a non-human primate (NHP) study to evaluate cognitive, behavioural, and brain functional and structural alterations after isoflurane exposure during infancy. These NHPs displayed decreased close social behaviour and increased astrogliosis in specific brain regions, most notably in the amygdala. Here we hypothesise that resting-state functional connectivity MRI can detect alterations in connectivity of brain areas that relate to these social behaviours and astrogliosis.

METHODS

Imaging was performed in 2-yr-old NHPs under light anaesthesia, after early-in-life (postnatal days 6-12) exposure to 5 h of isoflurane either one or three times, or to room air. Brain images were segmented into 82 regions of interest; the amygdala and the posterior cingulate cortex were chosen for a seed-based resting-state functional connectivity MRI analysis.

RESULTS

We found differences between groups in resting-state functional connectivity of the amygdala and the auditory cortices, medial premotor cortex, and posterior cingulate cortex. There were also alterations in resting-state functional connectivity between the posterior cingulate cortex and secondary auditory, polar prefrontal, and temporal cortices, and the anterior insula. Relationships were identified between resting-state functional connectivity alterations and the decrease in close social behaviour and increased astrogliosis.

CONCLUSIONS

Early-in-life anaesthesia exposure in NHPs is associated with resting-state functional connectivity alterations of the amygdala and the posterior cingulate cortex with other brain regions, evident at the juvenile age of 2 yr. These changes in resting-state functional connectivity correlate with the decrease in close social behaviour and increased astrogliosis. Using resting-state functional connectivity MRI to study the neuronal underpinnings of early-in-life anaesthesia-induced behavioural alterations could facilitate development of a biomarker for anaesthesia-induced developmental neurotoxicity.

Nuanced contribution of gut microbiome in the early brain development of mice

The complex symbiotic relationship between the mammalian body and gut microbiome plays a critical role in the health outcomes of offspring later in life. The gut microbiome modulates virtually all physiological functions through direct or indirect interactions to maintain physiological homeostasis. Previous studies indicate a link between maternal/early-life gut microbiome, brain development, and behavioral outcomes relating to social cognition. Here we present direct evidence of the role of the gut microbiome in brain development. Through magnetic resonance imaging (MRI), we investigated the impact of the gut microbiome on brain organization and structure using germ-free (GF) mice and conventionalized mice, with the gut microbiome reintroduced after weaning. We found broad changes in brain volume in GF mice that persist despite the reintroduction of gut microbes at weaning. These data suggest a direct link between the maternal gut or early-postnatal microbe and their impact on brain developmental programming.

Romania's Abandoned Children: The Effects of Early Profound Psychosocial Deprivation on the Course of Human Development

Understanding the impact that early psychosocial neglect has on the course of human development has implications for the millions of children around the world who are living in contexts of adversity. In the US, approximately 76% of cases reported to child protective services involve neglect; world-wide, there are more than 150 million orphaned or abandoned children, including 10.5 million orphaned because of COVID-19. In much of the world, children without primary caregivers are reared in institutional settings. We review two decades of research based on the only randomized controlled trial of foster care as an alternative to institutional care. We report that children randomly assigned to continued care as usual (institutional care) suffer from persistent deficits in social, cognitive, and emotional development, and show evidence of disruptions in brain development. By contrast, children randomly assigned to foster care show improvements in most domains of functioning, although the degree of recovery is in part a function of how old they were when placed into foster care and the stability of that placement. These findings have important implications for understanding critical periods in human development, as well as elucidating the power of the psychosocial environment in shaping multiple domains of human development.

The molecular genetic landscape of human brain size variation

Human brain size changes dynamically through early development, peaks in adolescence, and varies up to 2-fold among adults. However, the molecular genetic underpinnings of interindividual variation in brain size remain unknown. Here, we leveraged postmortem brain RNA sequencing and measurements of brain weight (BW) in 2,531 individuals across three independent datasets to identify 928 genome-wide significant associations with BW. Genes associated with higher or lower BW showed distinct neurodevelopmental trajectories and spatial patterns that mapped onto functional and cellular axes of brain organization. Expression of BW genes was predictive of interspecies differences in brain size, and bioinformatic annotation revealed enrichment for neurogenesis and cell-cell communication. Genome-wide, transcriptome-wide, and phenome-wide association analyses linked BW gene sets to neuroimaging measurements of brain size and brain-related clinical traits. Cumulatively, these results represent a major step toward delineating the molecular pathways underlying human brain size variation in health and disease.

Early visual experience refines the retinotopic organization within and across visual cortical regions

Early visual areas are retinotopically organized in human and non-human primates. Population receptive field (pRF) size increases with eccentricity and from lower- to higher-level visual areas. Furthermore, the cortical magnification factor (CMF), a measure of how much cortical space is devoted to each degree of visual angle, is typically larger for foveal as opposed to peripheral regions of the visual field. Whether this fine-scale organization within and across visual areas depends on early visual experience has yet been unknown. Here, we employed 7T functional magnetic resonance imaging pRF mapping to assess the retinotopic organization of early visual regions (i.e., V1, V2, and V3) in eight sight recovery individuals with a history of congenital blindness until a maximum of 4 years of age. Compared with sighted controls, foveal pRF sizes in these individuals were larger, and pRF sizes did not show the typical increase with eccentricity and down the visual cortical processing stream (V1-V2-V3). Cortical magnification was overall diminished and decreased less from foveal to parafoveal visual field locations. Furthermore, cortical magnification correlated with visual acuity in sight recovery individuals. The results of this study suggest that early visual experience is essential for refining a presumably innate prototypical retinotopic organization in humans within and across visual areas, which seems to be crucial for acquiring full visual capabilities.

Melatonin in Neurodevelopmental Disorders: A Critical Literature Review

The article presents a review of the relationships between melatonin and neurodevelopmental disorders. First, the antioxidant properties of melatonin and its physiological effects are considered to understand better the role of melatonin in typical and atypical neurodevelopment. Then, several neurodevelopmental disorders occurring during infancy, such as autism spectrum disorder or neurogenetic disorders associated with autism (including Smith-Magenis syndrome, Angelman syndrome, Rett's syndrome, Tuberous sclerosis, or Williams-Beuren syndrome) and neurodevelopmental disorders occurring later in adulthood like bipolar disorder and schizophrenia, are discussed with regard to impaired melatonin production and circadian rhythms, in particular, sleep-wake rhythms. This article addresses the issue of overlapping symptoms that are commonly observed within these different mental conditions and debates the role of abnormal melatonin production and altered circadian rhythms in the pathophysiology and behavioral expression of these neurodevelopmental disorders.

Neural tracking of social hierarchies in adolescents' real-world social networks

In the current study, we combined sociometric nominations and neuroimaging techniques to examine adolescents' neural tracking of peers from their real-world social network that varied in social preferences and popularity. Adolescent participants from an entire school district (N = 873) completed peer sociometric nominations of their grade at school, and a subset of participants (N = 117, Mage = 13.59 years) completed a neuroimaging task in which they viewed peer faces from their social networks. We revealed two neural processes by which adolescents track social preference: (1) the fusiform face area, an important region for early visual perception and social categorization, simultaneously represented both peers high in social preference and low in social preference; (2) the dorsolateral prefrontal cortex (DLPFC), which was differentially engaged in tracking peers high and low in social preference. No regions specifically tracked peers high in popularity and only the inferior parietal lobe, temporoparietal junction, midcingulate cortex and insula were involved in tracking unpopular peers. This is the first study to examine the neural circuits that support adolescents' perception of peer-based social networks. These findings identify the neural processes that allow youths to spontaneously keep track of peers' social value within their social network.

Study of lncRNAs in Pediatric Neurological Diseases: Methods, Analysis of the State-of-Art and Possible Therapeutic Implications

Long non-coding RNAs (lncRNAs) have emerged as crucial regulators in various cellular processes, and their roles in pediatric neurological diseases are increasingly being explored. This review provides an overview of lncRNA implications in the central nervous system, both in its physiological state and when a pathological condition is present. We describe the role of lncRNAs in neural development, highlighting their significance in processes such as neural stem cell proliferation, differentiation, and synaptogenesis. Dysregulation of specific lncRNAs is associated with multiple pediatric neurological diseases, such as neurodevelopmental or neurodegenerative disorders and brain tumors. The collected evidence indicates that there is a need for further research to uncover the full spectrum of lncRNA involvement in pediatric neurological diseases and brain tumors. While challenges exist, ongoing advancements in technology and our understanding of lncRNA biology offer hope for future breakthroughs in the field of pediatric neurology, leveraging lncRNAs as potential therapeutic targets and biomarkers.

A normative model of brain responses to social scenarios reflects the maturity of children and adolescents' social-emotional abilities

The rapid brain maturation in childhood and adolescence accompanies the development of socio-emotional functioning. However, it is unclear how the maturation of the neural activity drives the development of socio-emotional functioning and individual differences. This study aimed to reflect the age dependence of inter-individual differences in brain responses to socio-emotional scenarios and to develop naturalistic imaging indicators to assess the maturity of socio-emotional ability at the individual level. Using three independent naturalistic imaging datasets containing healthy participants (n = 111, 21 and 122), we found and validated that age-modulated inter-individual concordance of brain responses to socio-emotional movies in specific brain regions. The similarity of an individual's brain response to the average response of older participants was defined as response typicality, which predicted an individual's emotion regulation strategies in adolescence and theory of mind (ToM) in childhood. Its predictive power was not superseded by age, sex, cognitive performance or executive function. We further showed that the movie's valence and arousal ratings grounded the response typicality. The findings highlight that forming typical brain response patterns may be a neural phenotype underlying the maturation of socio-emotional ability. The proposed response typicality represents a neuroimaging approach to measure individuals' maturity of cognitive reappraisal and ToM.

Brain plasticity following corpus callosum agenesis or loss: a review of the Probst bundles

The corpus callosum is the largest axonal tract in the human brain, connecting the left and right cortical hemipheres. This structure is affected in myriad human neurodevelopmental disorders, and can be entirely absent as a result of congenital or surgical causes. The age when callosal loss occurs, for example via surgical section in cases of refractory epilepsy, correlates with resulting brain morphology and neuropsychological outcomes, whereby an earlier loss generally produces relatively improved interhemispheric connectivity compared to a loss in adulthood (known as the "Sperry's paradox"). However, the mechanisms behind these age-dependent differences remain unclear. Perhaps the best documented and most striking of the plastic changes that occur due to developmental, but not adult, callosal loss is the formation of large, bilateral, longitudinal ectopic tracts termed Probst bundles. Despite over 100 years of research into these ectopic tracts, which are the largest and best described stereotypical ectopic brain tracts in humans, much remains unclear about them. Here, we review the anatomy of the Probst bundles, along with evidence for their faciliatory or detrimental function, the required conditions for their formation, patterns of etiology, and mechanisms of development. We provide hypotheses for many of the remaining mysteries of the Probst bundles, including their possible relationship to preserved interhemispheric communication following corpus callosum absence. Future research into naturally occurring plastic tracts such as Probst bundles will help to inform the general rules governing axon plasticity and disorders of brain miswiring.

Altered gray-to-white matter tissue contrast in preterm-born adults

AIMS

To investigate cortical organization in brain magnetic resonance imaging (MRI) of preterm-born adults using percent contrast of gray-to-white matter signal intensities (GWPC), which is an in vivo proxy measure for cortical microstructure.

METHODS

Using structural MRI, we analyzed GWPC at different percentile fractions across the cortex (0%, 10%, 20%, 30%, 40%, 50%, and 60%) in a large and prospectively collected cohort of 86 very preterm-born (<32 weeks of gestation and/or birth weight <1500 g, VP/VLBW) adults and 103 full-term controls at 26 years of age. Cognitive performance was assessed by full-scale intelligence quotient (IQ) using the Wechsler Adult Intelligence Scale.

RESULTS

GWPC was significantly decreased in VP/VLBW adults in frontal, parietal, and temporal associative cortices, predominantly in the right hemisphere. Differences were pronounced at 20%, 30%, and 40%, hence, in middle cortical layers. GWPC was significantly increased in right paracentral lobule in VP/VLBW adults. GWPC in frontal and temporal cortices was positively correlated with birth weight, and negatively with duration of ventilation (p < 0.05). Furthermore, GWPC in right paracentral lobule was negatively correlated with IQ (p < 0.05).

CONCLUSIONS

Widespread aberrant gray-to-white matter contrast suggests lastingly altered cortical microstructure after preterm birth, mainly in middle cortical layers, with differential effects on associative and primary cortices.

Socioeconomic Status and Reading Development: Moving from "Deficit" to "Adaptation" in Neurobiological Models of Experience-Dependent Learning

Childhood socioeconomic status (SES) is one of the strongest predictors of student reading outcomes, and these disparities have persisted for decades. Relatedly, two underlying skills that are required for successful reading-oral language and executive function (EF)-are also the two neurocognitive domains most affected by SES. In this review, we summarize current knowledge on how SES influences the neurobiology of language, EF, and their intersection, including the proximal factors that drive these relationships. We then consider the burgeoning evidence that SES systematically moderates certain brain-behavior relationships for language and EF, underscoring the importance of considering context in investigations of the neurobiological underpinnings of reading development. Finally, we discuss how disparities in reading may be conceptualized as neurobiological adaptations to adversity rather than deficit models. We conclude by suggesting that by harnessing children's stress-adapted relative strengths to support reading development, we may address opportunity gaps both ethically and efficaciously.

Brain developmental and cortical connectivity changes in transgenic monkeys carrying the human-specific duplicated gene SRGAP2C

Human-specific duplicated genes contributed to phenotypic innovations during the origin of our own species, such as an enlarged brain and highly developed cognitive abilities. While prior studies on transgenic mice carrying the human-specific SRGAP2C gene have shown enhanced brain connectivity, the relevance to humans remains unclear due to the significant evolutionary gap between humans and rodents. In this study, to investigate the phenotypic outcome and underlying genetic mechanism of SRGAP2C, we generated transgenic cynomolgus macaques (Macaca fascicularis) carrying the human-specific SRGAP2C gene. Longitudinal MRI imaging revealed delayed brain development with region-specific volume changes, accompanied by altered myelination levels in the temporal and occipital regions. On a cellular level, the transgenic monkeys exhibited increased deep-layer neurons during fetal neurogenesis and delayed synaptic maturation in adolescence. Moreover, transcriptome analysis detected neotenic expression in molecular pathways related to neuron ensheathment, synaptic connections, extracellular matrix and energy metabolism. Cognitively, the transgenic monkeys demonstrated improved motor planning and execution skills. Together, our findings provide new insights into the mechanisms by which the newly evolved gene shapes the unique development and circuitry of the human brain.

Multi-echo Acquisition and Thermal Denoising Advances Infant Precision Functional Imaging

The characterization of individual functional brain organization with Precision Functional Mapping has provided important insights in recent years in adults. However, little is known about the ontogeny of inter-individual differences in brain functional organization during human development, but precise characterization of systems organization during periods of high plasticity might be most influential towards discoveries promoting lifelong health. Collecting and analyzing precision fMRI data during early development has unique challenges and emphasizes the importance of novel methods to improve data acquisition, processing, and analysis strategies in infant samples. Here, we investigate the applicability of two such methods from adult MRI research, multi-echo (ME) data acquisition and thermal noise removal with Noise reduction with distribution corrected principal component analysis (NORDIC), in precision fMRI data from three newborn infants. Compared to an adult example subject, T2* relaxation times calculated from ME data in infants were longer and more variable across the brain, pointing towards ME acquisition being a promising tool for optimizing developmental fMRI. The application of thermal denoising via NORDIC increased tSNR and the overall strength of functional connections as well as the split-half reliability of functional connectivity matrices in infant ME data. While our findings related to NORDIC denoising are coherent with the adult literature and ME data acquisition showed high promise, its application in developmental samples needs further investigation. The present work reveals gaps in our understanding of the best techniques for developmental brain imaging and highlights the need for further developmentally-specific methodological advances and optimizations, towards precision functional imaging in infants.

Impact of a Nutrient Formulation on Longitudinal Myelination, Cognition, and Behavior from Birth to 2 Years: A Randomized Clinical Trial

Observation studies suggest differences in myelination in relation to differences in early life nutrition. This two-center randomized controlled trial investigates the effect of a 12-month nutritional intervention on longitudinal changes in myelination, cognition, and behavior. Eighty-one full-term, neurotypical infants were randomized into an investigational (N = 42) or a control group (N = 39), receiving higher versus lower levels of a blend of nutrients. Non-randomized breastfed infants (N = 108) served as a reference group. Main outcomes were myelination (MRI), neurodevelopment (Bayley-III), social-emotional development (ASQ:SE-2), infant and toddler behavior (IBQ-R and TBAQ), and infant sleep (BISQ) during the first 2 years of life. The full analysis set comprised N = 67 infants from the randomized groups, with 81 myelin-sensitive MRI sequences. Significantly higher myelination was observed in the investigational compared to the control group at 6, 12, 18, and 24 months of life, as well as significantly higher gray matter volume at 24 months, a reduced number of night awakenings at 6 months, increased day sleep at 12 months, and reduced social fearfulness at 24 months. The results suggest that brain development may be modifiable with brain- and age-relevant nutritional approaches in healthy infants and young children, which may be foundational for later learning outcomes.

The adaptive stochasticity hypothesis: Modeling equifinality, multifinality, and adaptation to adversity

Neural phenotypes are the result of probabilistic developmental processes. This means that stochasticity is an intrinsic aspect of the brain as it self-organizes over a protracted period. In other words, while both genomic and environmental factors shape the developing nervous system, another significant-though often neglected-contributor is the randomness introduced by probability distributions. Using generative modeling of brain networks, we provide a framework for probing the contribution of stochasticity to neurodevelopmental diversity. To mimic the prenatal scaffold of brain structure set by activity-independent mechanisms, we start our simulations from the medio-posterior neonatal rich club (Developing Human Connectome Project, n = 630). From this initial starting point, models implementing Hebbian-like wiring processes generate variable yet consistently plausible brain network topologies. By analyzing repeated runs of the generative process (>107 simulations), we identify critical determinants and effects of stochasticity. Namely, we find that stochastic variation has a greater impact on brain organization when networks develop under weaker constraints. This heightened stochasticity makes brain networks more robust to random and targeted attacks, but more often results in non-normative phenotypic outcomes. To test our framework empirically, we evaluated whether stochasticity varies according to the experience of early-life deprivation using a cohort of neurodiverse children (Centre for Attention, Learning and Memory; n = 357). We show that low-socioeconomic status predicts more stochastic brain wiring. We conclude that stochasticity may be an unappreciated contributor to relevant developmental outcomes and make specific predictions for future research.

Redox-Mediated Rewiring of Signalling Pathways: The Role of a Cellular Clock in Brain Health and Disease

Metazoan signalling pathways can be rewired to dampen or amplify the rate of events, such as those that occur in development and aging. Given that a linear network topology restricts the capacity to rewire signalling pathways, such scalability of the pace of biological events suggests the existence of programmable non-linear elements in the underlying signalling pathways. Here, we review the network topology of key signalling pathways with a focus on redox-sensitive proteins, including PTEN and Ras GTPase, that reshape the connectivity profile of signalling pathways in response to an altered redox state. While this network-level impact of redox is achieved by the modulation of individual redox-sensitive proteins, it is the population by these proteins of critical nodes in a network topology of signal transduction pathways that amplifies the impact of redox-mediated reprogramming. We propose that redox-mediated rewiring is essential to regulate the rate of transmission of biological signals, giving rise to a programmable cellular clock that orchestrates the pace of biological phenomena such as development and aging. We further review the evidence that an aberrant redox-mediated modulation of output of the cellular clock contributes to the emergence of pathological conditions affecting the human brain.

Effect of neonatal melatonin administration on behavioral and brain electrophysiological and redox imbalance in rats

Introduction

Melatonin (MLT) reportedly has beneficial effects in neurological disorders involving brain excitability (e.g., Epilepsy and Migraine) and behavioral patterns (e.g., Anxiety and Depression). This study was performed to investigate, in the developing rat brain, the effect of early-in-life administration of two different doses of exogenous MLT on behavioral (anxiety and memory) and electrophysiological (CSD analysis) aspects of brain function. Additionally, brain levels of malondialdehyde (MDA) and superoxide dismutase (SOD), both cellular indicators of redox balance status, were evaluated. We hypothesize that MLT differentially affects the behavioral and CSD parameters as a function of the MLT dose.

Materials and methods

Male Wistar rats received, from the 7th to the 27th postnatal day (PND), on alternate days, vehicle solution, or 10 mg/kg/or 40 mg/kg MLT (MLT-10 and MLT-40 groups), or no treatment (intact group). To perform behavioral and cognition analysis, from PND30 to PND32, they were tested in the open field apparatus, first for anxiety (PND30) and then for object recognition memory tasks: spatial position recognition (PND31) and shape recognition (PND32). On PND34, they were tested in the elevated plus maze. From PND36 to 42, the excitability-related phenomenon known as cortical spreading depression (CSD) was recorded, and its features were analyzed.

Results

Treatment with MLT did not change the animals' body weight or blood glucose levels. The MLT-10 treatment, but not the MLT-40 treatment, was associated with behaviors that suggest less anxiety and improved memory. MLT-10 and MLT-40 treatments, respectively, decelerated and accelerated CSD propagation (speed of 2.86 ± 0.14 mm/min and 3.96 ± 0.16 mm/min), compared with the control groups (3.3 ± 0.10 mm/min and 3.25 ± 0.11 mm/min, for the intact and vehicle groups, respectively; p < 0.01). Cerebral cortex levels of malondialdehyde and superoxide dismutase were, respectively, lower and higher in the MLT-10 group but not in the MLT40 group.

Conclusion

Our findings suggest that MLT intraperitoneal administration during brain development may differentially act as an antioxidant agent when administered at a low dose but not at a high dose, according to behavioral, electrophysiological, and biochemical parameters.

1H-MRS neurometabolite profiles and motor development in school-aged children who are HIV-exposed uninfected: a birth cohort study

Objective

Alterations in regional neurometabolite levels as well as impaired neurodevelopmental outcomes have previously been observed in children who are HIV-exposed uninfected (CHEU). However, little is known about how neurometabolite profiles may relate to their developmental impairment. This study aimed to compare neurometabolite concentrations in school-aged CHEU and children who are HIV-unexposed (CHU) and to explore associations of neurometabolite profiles with functional neurodevelopment in the context of perinatal HIV exposure.

Methods

We used 3 T single voxel proton magnetic resonance spectroscopy (1H-MRS) to quantify absolute and relative neurometabolites in the parietal gray and parietal white matter in school-aged CHEU and aged- and community-matched CHU. Functional neurodevelopmental outcomes were assessed using the early learning outcome measure (ELOM) tool at 6 years of age.

Results

Our study included 152 school-aged children (50% males), 110 CHEU and 42 CHU, with an average age of 74 months at the neuroimaging visit. In an adjusted multiple linear regression analysis, significantly lower glutamate (Glu) concentrations were found in CHEU as compared to CHU in the parietal gray matter (absolute Glu, p = 0.046; Glu/total creatine (Cr+PCr) ratios, p = 0.035) and lower total choline to creatine ratios (GPC+PCh/Cr+PCr) in the parietal white matter (p = 0.039). Using factor analysis and adjusted logistic regression analysis, a parietal gray matter Glu and myo-inositol (Ins) dominated factor was associated with HIV exposure status in both unadjusted (OR 0.55, 95% CI 0.17-0.45, p = 0.013) and adjusted analyses (OR 0.59, 95% CI 0.35-0.94, p = 0.031). With Ins as one of the dominating metabolites, this neurometabolic factor was similar to that found at the age of two years. Furthermore, this factor was also found to be correlated with ELOM scores of gross motor development in CHEU (Pearson's r = -0.48, p = 0.044). In addition, in CHEU, there was a significant association between Ins/Cr+PCr ratios in the parietal white matter and ELOM scores of fine motor coordination and visual motor integration in CHEU (Pearson's r = 0.51, p = 0.032).

Conclusion

Reduced Glu concentrations in the parietal gray matter may suggest regional alterations in excitatory glutamatergic transmission pathways in the context of perinatal HIV and/or antiretroviral therapy (ART) exposure, while reduced Cho ratios in the parietal white matter suggest regional myelin loss. Identified associations between neurometabolite profiles and gross and fine motor developmental outcomes in CHEU are suggestive of a neurometabolic mechanism that may underlie impaired motor neurodevelopmental outcomes observed in CHEU.

Effects of prenatal bisphenol S and bisphenol F exposure on behavior of offspring mice

Bisphenol A (BPA) is a representative endocrine-disrupting chemical that exhibits hormonal disturbance reactions. Various alternatives, such as Bisphenol S (BPS) and Bisphenol F (BPF), are being developed. BPS and BPF (which are representative alternatives to BPA) are used in consumer products such as polycarbonate plastics and epoxy resins. They have structures similar to those of BPA and have also been proven to be exogenous endocrine disruptors. However, although there are many studies on BPA, there are few studies on the neurodevelopmental effects of BPS and BPF. Therefore, in this study, we analyzed neurobehavioral changes in offspring mice exposed to BPS and BPF during brain development by administering BPS and BPF to pregnant mice. We found that prenatal exposure to BPS and BPF did not affect anxiety-and depression-like behaviors, locomotion, sociability, memory, or cognition functions in offspring mice. However, exposure to BPS and BPF decreased the preference for social novelty in the offspring mice. Taken together, these findings suggest that perinatal exposure to BPS and BPF affects changes in social behaviors, but not other behavioral changes such as emotion, memory, or cognition in the offspring mice.

Intracellular traffic and polarity in brain development

Neurons forming the human brain are generated during embryonic development by neural stem and progenitor cells via a process called neurogenesis. A crucial feature contributing to neural stem cell morphological and functional heterogeneity is cell polarity, defined as asymmetric distribution of cellular components. Cell polarity is built and maintained thanks to the interplay between polarity proteins and polarity-generating organelles, such as the endoplasmic reticulum (ER) and the Golgi apparatus (GA). ER and GA affect the distribution of membrane components and work as a hub where glycans are added to nascent proteins and lipids. In the last decades our knowledge on the role of polarity in neural stem and progenitor cells have increased tremendously. However, the role of traffic and associated glycosylation in neural stem and progenitor cells is still relatively underexplored. In this review, we discuss the link between cell polarity, architecture, identity and intracellular traffic, and highlight how studies on neurons have shaped our knowledge and conceptual framework on traffic and polarity. We will then conclude by discussing how a group of rare diseases, called congenital disorders of glycosylation (CDG) offers the unique opportunity to study the contribution of traffic and glycosylation in the context of neurodevelopment.

Thyroid hormone action during GABAergic neuron maturation: The quest for mechanisms

Thyroid hormone (TH) signaling plays a major role in mammalian brain development. Data obtained in the past years in animal models have pinpointed GABAergic neurons as a major target of TH signaling during development, which opens up new perspectives to further investigate the mechanisms by which TH affects brain development. The aim of the present review is to gather the available information about the involvement of TH in the maturation of GABAergic neurons. After giving an overview of the kinds of neurological disorders that may arise from disruption of TH signaling during brain development in humans, we will take a historical perspective to show how rodent models of hypothyroidism have gradually pointed to GABAergic neurons as a main target of TH signaling during brain development. The third part of this review underscores the challenges that are encountered when conducting gene expression studies to investigate the molecular mechanisms that are at play downstream of TH receptors during brain development. Unravelling the mechanisms of action of TH in the developing brain should help make progress in the prevention and treatment of several neurological disorders, including autism and epilepsy.

Cognitive Enhancement and Social Mobility: Skepticism from India

Cognitive enhancement (CE) covers a broad spectrum of methods, including behavioral techniques, nootropic drugs, and neuromodulation interventions. However, research on their use in children has almost exclusively been carried out in high-income countries with limited understanding of how experts working with children view their use in low- and middle- income countries (LMICs). This study examines perceptions on cognitive enhancement, their techniques, neuroethical issues about their use from an LMICs perspective.Seven Indian experts were purposively sampled for their expertise in bioethics, child development and child education. In-depth interviews were conducted using a semi-structured topic guide to examine (1) understanding of CE, (2) which approaches were viewed as cognitive enhancers, (3) attitudes toward different CE techniques and (4) neuroethical issues related to CE use within the Indian context. All interviews were audio recorded and transcribed before thematic analysis.Findings indicate Indian experts view cognitive enhancement as a holistic positive impact on overall functioning and well-being, rather than improvement in specific cognitive abilities. Exogenous agents, and neuromodulation were viewed with skepticism, whereas behavioral approaches were viewed more favorably. Neuroethical concerns included equitable access to CE, limited scientific evidence and over-reliance on technology to address societal problems. This highlights the need for more contextually relevant neuroethics research in LMICs.

Autophagy in synapse formation and brain wiring

A recent characterization of the role of autophagy in two different neuron types during brain development in Drosophila revealed two different mechanisms to regulate synapse formation. In photoreceptor neurons, autophagosome formation in synaptogenic filopodia destabilizes presumptive synaptic contacts and thereby restricts incorrect synaptic partnerships. In dorsal cluster neurons, autophagy is actively suppressed to keep mature synapses stable during axonal branching. These findings indicate that different neuron types can require activation or suppression of synaptic autophagy during the same developmental period to ensure proper synapse formation and brain connectivity.

Marginal Zinc Deficiency during Gestation and Lactation in Rats Affects Oligodendrogenesis, Motor Performance, and Behavior in the Offspring

BACKGROUND

Oligodendrocytes are responsible for myelin production in the central nervous system (CNS). Hypomyelination may slow saltatory nerve signal conduction and affect motor performance and behavior in adults. Gestational marginal zinc deficiency in rats significantly decreases proliferation of neural stem cells (NSCs) in the offspring brain.

OBJECTIVES

Given that NSCs are precursors of oligodendrocytes, this study investigated if marginal zinc deficiency during early development in rats affects oligodendrogenesis in the offspring's CNS.

METHODS

Rat dams were fed an adequate (25 μg zinc/g diet) (C) or a marginal zinc diet (MZD) (10 μg zinc/g diet), from gestation day zero until postnatal day (P) 20, and subsequently all offspring was fed the control diet until P60. Oligodendrogenesis was evaluated in the offspring at P2, P5, P10, P20, and P60, by measuring parameters of oligodendrocyte progenitor cells (OPCs) proliferation, differentiation, maturation, and of myelination.

RESULTS

The expression of 1) proteins that regulate OPC proliferation (Shh, Sox10, Olig2); 2) OPC markers (NG2, PDGFRα); 3) myelin proteins (MBP, MAG, MOG, PLP) were lower in the brain cortex from MZD than C offspring at various stages in development. The amount of myelin after zinc replenishment continued to be low in the MZD young adult at P60. Accordingly, parameters of motor performance and behavior [grip strength, rotarod, elevated T-maze (ETM), and open-field tests] were impaired in the MZD offspring at P60.

CONCLUSIONS

Results support the concept that maternal and early postnatal exposure to MZD affects oligodendrogenesis causing long-lasting effects on myelination and on motor performance in the young adult offspring.

Hippocampal and amygdala volumes vary with residential proximity to toxicants at Birmingham, Alabama's 35th Avenue Superfund site

Exposure to environmental toxicants have serious implications for the general health and well-being of children, particularly during pivotal neurodevelopmental stages. The Environmental Protection Agency's (EPA) Superfund program has identified several areas (Superfund sites) across the United States with high levels of environmental toxicants, which affect the health of many residents in nearby communities. Exposure to these environmental toxicants has been linked to changes in the structure and function of the brain. However, limited research has investigated the relationship between the proximity of childhood homes to a Superfund site and the development of subcortical structures like the hippocampus and amygdala. The present study investigated the hippocampal and amygdala volumes of young adults in relation to the proximity of their childhood homes to Birmingham, Alabama's 35th Avenue Superfund site. Forty participants who either lived within or adjacent to the Superfund site (Proximal group; n = 20) or who lived elsewhere in the greater Birmingham metropolitan area (Distal group; n = 20) were included in this study. Both groups were matched on age, sex, race, and years of education. Magnetic resonance imaging (MRI) was used to compare the gray matter volume of the hippocampus and amygdala between groups. Differences in bilateral hippocampal and left amygdala volumes were observed. Specifically, hippocampal and amygdala volumes were greater in the Proximal than Distal group. These findings suggest that the proximity of children's homes to environmental toxicants may impact the development of the hippocampus and amygdala. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Cdc7 kinase is required for postnatal brain development

The evolutionally conserved Cdc7 kinase plays crucial roles in initiation of DNA replication as well as in other chromosomal events. To examine the roles of Cdc7 in brain development, we have generated mice carrying Cdc7 knockout in neural stem cells by using Nestin-Cre. The Cdc7Fl/Fl NestinCre mice were born, but exhibited severe growth retardation and impaired postnatal brain development. These mice exhibited motor dysfunction within 9 days after birth and did not survive for more than 19 days. The cerebral cortical layer formation was impaired, although the cortical cell numbers were not altered in the mutant. In the cerebellum undergoing hypoplasia, granule cells (CGC) decreased in number in Cdc7Fl/F l NestinCre mice compared to the control at E15-18, suggesting that Cdc7 is required for DNA replication and cell proliferation of CGC at mid embryonic stage (before embryonic day 15). On the other hand, the Purkinje cell numbers were not altered but its layer formation was impaired in the mutant. These results indicate differential roles of Cdc7 in DNA replication/cell proliferation in brain. Furthermore, the defects of layer formation suggest a possibility that Cdc7 may play an additional role in cell migration during neural development.

APPlications of amyloid-β precursor protein metabolites in macrocephaly and autism spectrum disorder

Metabolites of the Amyloid-β precursor protein (APP) proteolysis may underlie brain overgrowth in Autism Spectrum Disorder (ASD). We have found elevated APP metabolites (total APP, secreted (s) APPα, and α-secretase adamalysins in the plasma and brain tissue of children with ASD). In this review, we highlight several lines of evidence supporting APP metabolites' potential contribution to macrocephaly in ASD. First, APP appears early in corticogenesis, placing APP in a prime position to accelerate growth in neurons and glia. APP metabolites are upregulated in neuroinflammation, another potential contributor to excessive brain growth in ASD. APP metabolites appear to directly affect translational signaling pathways, which have been linked to single gene forms of syndromic ASD (Fragile X Syndrome, PTEN, Tuberous Sclerosis Complex). Finally, APP metabolites, and microRNA, which regulates APP expression, may contribute to ASD brain overgrowth, particularly increased white matter, through ERK receptor activation on the PI3K/Akt/mTOR/Rho GTPase pathway, favoring myelination.

Voluntary Running Improves Behavioral and Structural Abnormalities in a Mouse Model of CDKL5 Deficiency Disorder

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a rare neurodevelopmental disease caused by mutations in the X-linked CDKL5 gene. CDD is characterized by a broad spectrum of clinical manifestations, including early-onset refractory epileptic seizures, intellectual disability, hypotonia, visual disturbances, and autism-like features. The Cdkl5 knockout (KO) mouse recapitulates several features of CDD, including autistic-like behavior, impaired learning and memory, and motor stereotypies. These behavioral alterations are accompanied by diminished neuronal maturation and survival, reduced dendritic branching and spine maturation, and marked microglia activation. There is currently no cure or effective treatment to ameliorate the symptoms of the disease. Aerobic exercise is known to exert multiple beneficial effects in the brain, not only by increasing neurogenesis, but also by improving motor and cognitive tasks. To date, no studies have analyzed the effect of physical exercise on the phenotype of a CDD mouse model. In view of the positive effects of voluntary running on the brain of mouse models of various human neurodevelopmental disorders, we sought to determine whether voluntary daily running, sustained over a month, could improve brain development and behavioral defects in Cdkl5 KO mice. Our study showed that long-term voluntary running improved the hyperlocomotion and impulsivity behaviors and memory performance of Cdkl5 KO mice. This is correlated with increased hippocampal neurogenesis, neuronal survival, spine maturation, and inhibition of microglia activation. These behavioral and structural improvements were associated with increased BDNF levels. Given the positive effects of BDNF on brain development and function, the present findings support the positive benefits of exercise as an adjuvant therapy for CDD.

Developmental Mouse Brain Common Coordinate Framework

3D standard reference brains serve as key resources to understand the spatial organization of the brain and promote interoperability across different studies. However, unlike the adult mouse brain, the lack of standard 3D reference atlases for developing mouse brains has hindered advancement of our understanding of brain development. Here, we present a multimodal 3D developmental common coordinate framework (DevCCF) spanning mouse embryonic day (E) 11.5, E13.5, E15.5, E18.5, and postnatal day (P) 4, P14, and P56 with anatomical segmentations defined by a developmental ontology. At each age, the DevCCF features undistorted morphologically averaged atlas templates created from Magnetic Resonance Imaging and co-registered high-resolution templates from light sheet fluorescence microscopy. Expert-curated 3D anatomical segmentations at each age adhere to an updated prosomeric model and can be explored via an interactive 3D web-visualizer. As a use case, we employed the DevCCF to unveil the emergence of GABAergic neurons in embryonic brains. Moreover, we integrated the Allen CCFv3 into the P56 template with stereotaxic coordinates and mapped spatial transcriptome cell-type data with the developmental ontology. In summary, the DevCCF is an openly accessible resource that can be used for large-scale data integration to gain a comprehensive understanding of brain development.

A tribute to John Edmond: His leadership role in founding the International Conference on Brain Energy Metabolism (ICBEM) meetings and key contributions to substrate metabolism in brain cells

This is a tribute to John Edmond, professor emeritus of biological chemistry in the David Geffen School of Medicine at UCLA, a renowned neurochemist who had a leadership role in founding the ICBEM meeting series in 1993. John was known for his very warm and engaging personality and his innovative approaches to studying the developing brain and auditory system. He was a brilliant scientist and a fun and delightful person. Without John Edmond's enthusiasm and contributions, we would not have the biennial ICBEM meetings which as noted by Dienel et al. "have had a high impact on conceptual and experimental advances" … "in the energetics and metabolism underlying neural functions"… and "on promoting collaborative interactions among neuroscientists." Sadly, John Edmond passed away on February 18, 2022, following a cerebral hemorrhage. He will be greatly missed by his colleagues and friends.

Ribosomal RNA 2'-O-methylation dynamics impact cell fate decisions

Translational regulation impacts both pluripotency maintenance and cell differentiation. To what degree the ribosome exerts control over this process remains unanswered. Accumulating evidence has demonstrated heterogeneity in ribosome composition in various organisms. 2'-O-methylation (2'-O-me) of rRNA represents an important source of heterogeneity, where site-specific alteration of methylation levels can modulate translation. Here, we examine changes in rRNA 2'-O-me during mouse brain development and tri-lineage differentiation of human embryonic stem cells (hESCs). We find distinct alterations between brain regions, as well as clear dynamics during cortex development and germ layer differentiation. We identify a methylation site impacting neuronal differentiation. Modulation of its methylation levels affects ribosome association of the fragile X mental retardation protein (FMRP) and is accompanied by an altered translation of WNT pathway-related mRNAs. Together, these data identify ribosome heterogeneity through rRNA 2'-O-me during early development and differentiation and suggest a direct role for ribosomes in regulating translation during cell fate acquisition.

Effects of In Utero EtOH Exposure on 18S Ribosomal RNA Processing: Contribution to Fetal Alcohol Spectrum Disorder

Fetal alcohol spectrum disorders (FASD) are leading causes of neurodevelopmental disability. The mechanisms by which alcohol (EtOH) disrupts fetal brain development are incompletely understood, as are the genetic factors that modify individual vulnerability. Because the phenotype abnormalities of FASD are so varied and widespread, we investigated whether fetal exposure to EtOH disrupts ribosome biogenesis and the processing of pre-ribosomal RNAs and ribosome assembly, by determining the effect of exposure to EtOH on the developmental expression of 18S rRNA and its cleaved forms, members of a novel class of short non-coding RNAs (srRNAs). In vitro neuronal cultures and fetal brains (11-22 weeks) were collected according to an IRB-approved protocol. Twenty EtOH-exposed brains from the first and second trimester were compared with ten unexposed controls matched for gestational age and fetal gender. Twenty fetal-brain-derived exosomes (FB-Es) were isolated from matching maternal blood. RNA was isolated using Qiagen RNA isolation kits. Fetal brain srRNA expression was quantified by ddPCR. srRNAs were expressed in the human brain and FB-Es during fetal development. EtOH exposure slightly decreased srRNA expression (1.1-fold; p = 0.03). Addition of srRNAs to in vitro neuronal cultures inhibited EtOH-induced caspase-3 activation (1.6-fold, p = 0.002) and increased cell survival (4.7%, p = 0.034). The addition of exogenous srRNAs reversed the EtOH-mediated downregulation of srRNAs (2-fold, p = 0.002). EtOH exposure suppressed expression of srRNAs in the developing brain, increased activity of caspase-3, and inhibited neuronal survival. Exogenous srRNAs reversed this effect, possibly by stabilizing endogenous srRNAs, or by increasing the association of cellular proteins with srRNAs, modifying gene transcription. Finally, the reduction in 18S rRNA levels correlated closely with the reduction in fetal eye diameter, an anatomical hallmark of FASD. The findings suggest a potential mechanism for EtOH-mediated neurotoxicity via alterations in 18S rRNA processing and the use of FB-Es for early diagnosis of FASD. Ribosome biogenesis may be a novel target to ameliorate FASD in utero or after birth. These findings are consistent with observations that gene-environment interactions contribute to FASD vulnerability.

HNRNPU's multi-tasking is essential for proper cortical development

Heterogeneous nuclear ribonucleoprotein U (HNRNPU) is a nuclear protein that plays a crucial role in various biological functions, such as RNA splicing and chromatin organization. HNRNPU/scaffold attachment factor A (SAF-A) activities are essential for regulating gene expression, DNA replication, genome integrity, and mitotic fidelity. These functions are critical to ensure the robustness of developmental processes, particularly those involved in shaping the human brain. As a result, HNRNPU is associated with various neurodevelopmental disorders (HNRNPU-related neurodevelopmental disorder, HNRNPU-NDD) characterized by developmental delay and intellectual disability. Our research demonstrates that the loss of HNRNPU function results in the death of both neural progenitor cells and post-mitotic neurons, with a higher sensitivity observed in the former. We reported that HNRNPU truncation leads to the dysregulation of gene expression and alternative splicing of genes that converge on several signaling pathways, some of which are likely to be involved in the pathology of HNRNPU-related NDD.

Ex-utero third trimester developmental changes in functional brain network organization in infants born very and extremely preterm

Introduction

The latter half of gestation is a period of rapid brain development, including the formation of fundamental functional brain network architecture. Unlike in-utero fetuses, infants born very and extremely preterm undergo these critical maturational changes in the extrauterine environment, with growing evidence suggesting this may result in altered brain networks. To date, however, the development of functional brain architecture has been unexplored.

Methods

From a prospective cohort of preterm infants, graph parameters were calculated for fMRI scans acquired prior to reaching term equivalent age. Eight graph properties were calculated, Clustering Coefficient (C), Characteristic Path Length (L), Modularity (Q), Local Efficiency (LE), Global Efficiency (GE), Normalized Clustering (λ), Normalized Path Length (γ), and Small-Worldness (σ). Properties were first compared to values generated from random and lattice networks and cost efficiency was evaluated. Subsequently, linear mixed effect models were used to assess relationship with postmenstrual age and infant sex.

Results

A total of 111 fMRI scans were acquired from 85 preterm infants born at a mean GA 28.93 ± 2.8. Infants displayed robust small world properties as well as both locally and globally efficient networks. Regression models found that GE increased while L, Q, λ, γ, and σ decreased with increasing postmenstrual age following multiple comparison correction (r2Adj range 0.143-0.401, p < 0048), with C and LE exhibited trending increases with age.

Discussion

This is the first direct investigation on the extra-uterine formation of functional brain architecture in preterm infants. Importantly, our results suggest that changes in functional architecture with increasing age exhibit a different trajectory relative to in utero fetus. Instead, they exhibit developmental changes more similar to the early postnatal period in term born infants.

Lamin B1 as a key modulator of the developing and aging brain

Lamin B1 is an essential protein of the nuclear lamina that plays a crucial role in nuclear function and organization. It has been demonstrated that lamin B1 is essential for organogenesis and particularly brain development. The important role of lamin B1 in physiological brain development and aging has only recently been at the epicenter of attention and is yet to be fully elucidated. Regarding the development of brain, glial cells that have long been considered as supporting cells to neurons have overturned this representation and current findings have displayed their active roles in neurogenesis and cerebral development. Although lamin B1 has increased levels during the differentiation of the brain cells, during aging these levels drop leading to senescent phenotypes and inciting neurodegenerative disorders such as Alzheimer's and Parkinson's disease. On the other hand, overexpression of lamin B1 leads to the adult-onset neurodegenerative disease known as Autosomal Dominant Leukodystrophy. This review aims at highlighting the importance of balancing lamin B1 levels in glial cells and neurons from brain development to aging.

Developing brain under renewed attack: viral infection during pregnancy

Living in a globalized world, viral infections such as CHIKV, SARS-COV-2, and ZIKV have become inevitable to also infect the most vulnerable groups in our society. That poses a danger to these populations including pregnant women since the developing brain is sensitive to maternal stressors including viral infections. Upon maternal infection, the viruses can gain access to the fetus via the maternofetal barrier and even to the fetal brain during which factors such as viral receptor expression, time of infection, and the balance between antiviral immune responses and pro-viral mechanisms contribute to mother-to-fetus transmission and fetal infection. Both the direct pro-viral mechanisms and the resulting dysregulated immune response can cause multi-level impairment in the maternofetal and brain barriers and the developing brain itself leading to dysfunction or even loss of several cell populations. Thus, maternal viral infections can disturb brain development and even predispose to neurodevelopmental disorders. In this review, we discuss the potential contribution of maternal viral infections of three relevant relative recent players in the field: Zika, Chikungunya, and Severe Acute Respiratory Syndrome Coronavirus-2, to the impairment of brain development throughout the entire route.

Review on the Impact of Milk Oligosaccharides on the Brain and Neurocognitive Development in Early Life

Milk Oligosaccharides (MOS), a group of complex carbohydrates found in human and bovine milk, have emerged as potential modulators of optimal brain development for early life. This review provides a comprehensive investigation of the impact of milk oligosaccharides on brain and neurocognitive development of early life by synthesizing current literature from preclinical models and human observational studies. The literature search was conducted in the PubMed search engine, and the inclusion eligibility was evaluated by three reviewers. Overall, we identified 26 articles for analysis. While the literature supports the crucial roles of fucosylated and sialylated milk oligosaccharides in learning, memory, executive functioning, and brain structural development, limitations were identified. In preclinical models, the supplementation of only the most abundant MOS might overlook the complexity of naturally occurring MOS compositions. Similarly, accurately quantifying MOS intake in human studies is challenging due to potential confounding effects such as formula feeding. Mechanistically, MOS is thought to impact neurodevelopment through modulation of the microbiota and enhancement of neuronal signaling. However, further advancement in our understanding necessitates clinical randomized-controlled trials to elucidate the specific mechanisms and long-term implications of milk oligosaccharides exposure. Understanding the interplay between milk oligosaccharides and cognition may contribute to early nutrition strategies for optimal cognitive outcomes in children.

Transdiagnostic indicators predict developmental changes in cognitive control resting-state networks

Over the past decade, transdiagnostic indicators in relation to neurobiological processes have provided extensive insight into youth's risk for psychopathology. During development, exposure to childhood trauma and dysregulation (i.e., so-called AAA symptomology: anxiety, aggression, and attention problems) puts individuals at a disproportionate risk for developing psychopathology and altered network-level neural functioning. Evidence for the latter has emerged from resting-state fMRI studies linking mental health symptoms and aberrations in functional networks (e.g., cognitive control (CCN), default mode networks (DMN)) in youth, although few of these investigations have used longitudinal designs. Herein, we leveraged a three-year longitudinal study to identify whether traumatic exposures and concomitant dysregulation trigger changes in the developmental trajectories of resting-state functional networks involved in cognitive control (N = 190; 91 females; time 1 Mage = 11.81). Findings from latent growth curve analyses revealed that greater trauma exposure predicted increasing connectivity between the CCN and DMN across time. Greater levels of dysregulation predicted reductions in within-network connectivity in the CCN. These findings presented in typically developing youth corroborate connectivity patterns reported in clinical populations, suggesting there is predictive utility in using transdiagnostic indicators to forecast alterations in resting-state networks implicated in psychopathology.

Task-based functional neuroimaging in infants: a systematic review

Background

Infancy is characterized by rapid neurological transformations leading to consolidation of lifelong function capabilities. Studying the infant brain is crucial for understanding how these mechanisms develop during this sensitive period. We review the neuroimaging modalities used with infants in stimulus-induced activity paradigms specifically, for the unique opportunity the latter provide for assessment of brain function.

Methods

Conducted a systematic review of literature published between 1977-2021, via a comprehensive search of four major databases. Standardized appraisal tools and inclusion/exclusion criteria were set according to the PRISMA guidelines.

Results

Two-hundred and thirteen papers met the criteria of the review process. The results show clear evidence of overall cumulative growth in the number of infant functional neuroimaging studies, with electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) to be the most utilized and fastest growing modalities with behaving infants. However, there is a high level of exclusion rates associated with technical limitations, leading to limited motor control studies (about 6 % ) in this population.

Conclusion

Although the use of functional neuroimaging modalities with infants increases, there are impediments to effective adoption of existing technologies with this population. Developing new imaging modalities and experimental designs to monitor brain activity in awake and behaving infants is vital.

In utero ethanol exposure induces mitochondrial DNA damage and inhibits mtDNA repair in developing brain

Introduction

Mitochondrial dysfunction is postulated to be a central event in fetal alcohol spectrum disorders (FASD). People with the most severe form of FASD, fetal alcohol syndrome (FAS) are estimated to live only 34 years (95% confidence interval, 31 to 37 years), and adults who were born with any form of FASD often develop early aging. Mitochondrial dysfunction and mitochondrial DNA (mtDNA) damage, hallmarks of aging, are postulated central events in FASD. Ethanol (EtOH) can cause mtDNA damage, consequent increased oxidative stress, and changes in the mtDNA repair protein 8-oxoguanine DNA glycosylase-1 (OGG1). Studies of molecular mechanisms are limited by the absence of suitable human models and non-invasive tools.

Methods

We compared human and rat EtOH-exposed fetal brain tissues and neuronal cultures, and fetal brain-derived exosomes (FB-Es) from maternal blood. Rat FASD was induced by administering a 6.7% alcohol liquid diet to pregnant dams. Human fetal (11-21 weeks) brain tissue was collected and characterized by maternal self-reported EtOH use. mtDNA was amplified by qPCR. OGG1 and Insulin-like growth factor 1 (IGF-1) mRNAs were assayed by qRT-PCR. Exosomal OGG1 was measured by ddPCR.

Results

Maternal EtOH exposure increased mtDNA damage in fetal brain tissue and FB-Es. The damaged mtDNA in FB-Es correlated highly with small eye diameter, an anatomical hallmark of FASD. OGG1-mediated mtDNA repair was inhibited in EtOH-exposed fetal brain tissues. IGF-1 rescued neurons from EtOH-mediated mtDNA damage and OGG1 inhibition.

Conclusion

The correlation between mtDNA damage and small eye size suggests that the amount of damaged mtDNA in FB-E may serve as a marker to predict which at risk fetuses will be born with FASD. Moreover, IGF-1 might reduce EtOH-caused mtDNA damage and neuronal apoptosis.

Histone Variants and Their Chaperones: An Emerging Epigenetic Mechanism in Neurodevelopment and Neurodevelopmental Disorders

Neurodevelopment is a highly regulated process that relies on the precise regulation of gene expression. Numerous epigenetic mechanisms contribute and cooperate to ensure the proper execution of developmental gene expression programs. Indeed, disruption of the molecular machinery regulating the deposition or removal of epigenetics markers is associated with numerous neurodevelopmental disorders, including autism spectrum disorder and intellectual disabilities. Among the various epigenetic marks that are fundamental for brain development, research has recently begun to focus on the role of histone variants and their associated chaperone proteins. Replication-independent histone variants can replace replication-dependent canonical histones in neuronal chromatin, giving nucleosomes unique properties that allow them to influence transcription. The deposition and removal of histone variants into neuronal chromatin are controlled by chaperone proteins that are integrated into chromatin remodelling complexes. Several studies report that the deposition and removal of histone variants by chaperone proteins from genes during development is pivotal for the regulation of gene expression, suggesting they are fundamental for neurodevelopment. This review will focus on the histone variants H2A.Z and H3.3, and the exclusive chaperones that regulate their dynamics, in gene expression during neurodevelopment and the progression of neurodevelopmental disorders.

Correlative light and volume electron microscopy to study brain development

Recent advances in volume electron microscopy (EM) have been driving our thorough understanding of the brain architecture. Volume EM becomes increasingly powerful when cells and their subcellular structures that are imaged in light microscopy are correlated to those in ultramicrographs obtained with EM. This correlative approach, called correlative light and volume electron microscopy (vCLEM), is used to link three-dimensional ultrastructural information with physiological data such as intracellular Ca2+ dynamics. Genetic tools to express fluorescent proteins and/or an engineered form of a soybean ascorbate peroxidase allow us to perform vCLEM using natural landmarks including blood vessels without immunohistochemical staining. This immunostaining-free vCLEM has been successfully employed in two-photon Ca2+ imaging in vivo as well as in studying complex synaptic connections in thalamic neurons that receive a variety of specialized inputs from the cerebral cortex. In this mini-review, we overview how volume EM and vCLEM have contributed to studying the developmental processes of the brain. We also discuss potential applications of genetic manipulation of target cells using clustered regularly interspaced short palindromic repeats-associated protein 9 and subsequent volume EM to the analysis of protein localization as well as to loss-of-function studies of genes regulating brain development. We give examples for the combinatorial usage of genetic tools with vCLEM that will further enhance our understanding of regulatory mechanisms underlying brain development.

Does Ketogenic Diet Used in Pregnancy Affect the Nervous System Development in Offspring?─FTIR Microspectroscopy Study

Anti-seizure medications used during pregnancy may have transient or long-lasting impact on the nervous system of the offspring. Therefore, there is a great need to search for alternative therapies for pregnant women suffering from seizures. One of the solutions may be the use of the ketogenic diet (KD), which has been successfully applied as a treatment of drug-resistant epilepsy in children and adults. However, the risks associated with the use of this dietary therapy during pregnancy are unknown and more investigation in this area is needed. To shed some light on this problem, we attempted to determine the potential abnormalities in brain biomolecular composition that may occur in the offspring after the prenatal exposure to KD. To achieve this, the female Wistar rats were, during pregnancy, fed with either ketogenic or standard laboratory diet, and for further studies, their male offspring at 2, 6, or 14 days of age were used. Fourier transform infrared microspectroscopy was applied for topographic and quantitative analysis of main biological macromolecules (proteins, lipids, compounds containing phosphate and carbonyl groups, and cholesterol) in brain samples. Performed chemical mapping and further semi-quantitative and statistical analysis showed that the use of the KD during pregnancy, in general, does not lead to the brain biochemical anomalies in 2 and 6 days old rats. The exception from this rule was increased relative (comparing to proteins) content of compounds containing phosphate groups in white matter and cortex of 2 days old rats exposed prenatally to KD. Greater number of abnormalities was found in brains of the 14 days old offspring of KD-fed mothers. They included the increase of the relative level of compounds containing carbonyl groups (in cortex as well as multiform and molecular cells of the hippocampal formation) as well as the decrease of the relative content of lipids and their structural changes (in white matter). What is more, the surface of the internal capsule (structure of the white matter) determined for this age group was smaller in animals subjected to prenatal KD exposure. The observed changes seem to arise from the elevated exposition to ketone bodies during a fetus life and the disturbance of lipid metabolism after prenatal exposure to the KD. These changes may be also associated with the processes of compensation of mother organism, which slowly began to make up for the deficiencies in carbohydrates postpartum.