Brain networks in newborns and infants with and without sensorineural hearing loss:A functional near-infrared spectroscopy study

BACKGROUND Understanding the impact of early sensory deficits on brain development is essential for understanding developmental processes and developing potential interventions.While previous studies have looked into the impact of prenatal experiences on language development,there is a lack of research on how these experiences affect early language and brain function development in individuals with sensorineural hearing loss(SNHL).AIM To investigate SNHL effects on early brain development and connectivity in 4-month-olds vs healthy newborns and controls.METHODS The research involved analyzing the functional brain networks of 65 infants,categorized into three groups:28 healthy newborns,224-month-old participants with SNHL,and 15 age-matched healthy participants.The resting-state functional connectivity was measured and compared between the groups using functional near-infrared spectroscopy and graph theory to assess the brain network properties.RESULTS Significant differences were found in resting-state functional connectivity between participants with SNHL and age-matched controls,indicating a developmental lag in brain connectivity for those with SNHL.Surprisingly,SNHL participants showed better connectivity development compared to healthy newborns,with connectivity strengths of 0.13±0.04 for SNHL,0.16±0.08 for controls,and 0.098±0.04 for newborns.Graph theory analysis revealed enhanced global brain network properties for the SNHL group,suggesting higher communication efficiency at 4 months.No significant differences were noted in network properties between 4-month-old SNHL participants and neonates.A unique pattern of central hubs was observed in the SNHL group,with 2 hubs in the left hemisphere compared to 6 in controls.CONCLUSION 4-month-old infants with SNHL have a distinct brain network pattern with efficient long-distance information transmission but less effective local communication compared to age-matched controls.

Developmental changes of glutamate acid decarboxylase 67 in mouse brain after hypoxia ischemia

Objective To study the developmental changes of glutamic acid decarboxylase-67 （ GAD-67, a GABA synthetic enzyme） in normal and hypoxic ischemic （HI） brain. Methods C57/BL6 mice on postnatal day （P） 5, 9, 21 and 60, corresponding developmentally to premature, term, juvenile and adult human brain were investigated by using both Western blot and immunohistochemistry methods either in normal condition or after hypoxic ischemic insult. Results The immunoreactivity of GAD67 was up regulated with brain development and significant difference was seen between mature （P21, P60） and immature （P5, P9） brain. GAD67 immunoreactivity decreased in the ipsilateral hemisphere in all the ages after hypoxia ischemia （HI） insult, but, significant decrease was only seen in the immature brain. Double labeling of GAD67 and cell death marker, TUNEL, in the cortex at 8h post-HI in the P9 mice showed that （15.6±7.0）% TUNEL positive cells were GAD67 positive which was higher than that of P60 mice. Conclusion These data suggest that GABAergic neurons in immature brain were more vulnerable to HI insult than that of mature brain.

The effects of a 20-week exercise program on blood-circulating biomarkers related to brain health in overweight or obese children:The ActiveBrains project

Background:Emerging research supports the idea that exercise positively affects neurodevelopment.However,the mechanisms linking exercise with brain health are largely unknown.We aimed to investigate the effect of exercise on(a)blood biomarkers selected based on previous evidence(brainderived neurotrophic factor,β-hydroxybutyrate(BHB),cathepsin B(CTSB),kynurenine,fibroblast growth factor 21(FGF21),soluble vascular cell adhesion molecule-1(sVCAM-1));and(b)a panel of 92 neurology-related proteins(discovery analysis).We also investigated whether changes in these biomarkers mediate the effects of exercise on brain health(hippocampal structure and function,cognitive performance,and mental health).Methods:We randomized 81 overweight/obese children(10.1±1.1 years,41%girls)into 2 groups:either 20 weeks of aerobic plus resistance exercise or control.Candidate biomarkers were assessed using enzyme-linked immunosorbent assay(ELISA)for kynurenine,FGF21,and CTSB;colorimetry forβ-hydroxybutyrate;and XMap for brain-derived neurotrophic factor and soluble vascular cell adhesion molecule-1.The92 neurology-related proteins were analyzed by an antibody-based proteomic analysis.Results:Our intervention had no significant effect on candidate biomarkers(all p>0.05).In the discovery analysis,a reduction in circulating macrophage scavenger receptor type-I was observed(standardized differences between groups=-0.3,p=0.001).This effect was validated using ELISA methods(standardized difference=-0.3,p=0.01).None of the biomarkers mediated the effects of exercise on brain health.Conclusions:Our study does not support a chronic effect of exercise on candidate biomarkers.We observed that while chronic exercise reduced the levels of macrophage scavenger receptor type-Ⅰ,it did not mediate the effects of exercise on brain health.Future studies should explore the implications of this novel biomarker for overall health.

Changes of cell proliferation and differentiation in the developing brain of mouse

Objective To investigate the cell proliferation and differentiation in the developing brain of mouse. Methods C57/BL6 mice were divided into 3 groups at random. Bromodeoxyuridine （BrdU） was injected into the brains in different development periods once a day for 7 d. The brains were retrieved 4 weeks after the last BrdU injection. Immunohistochemical and immunofluorescent studies were carried out for detecting cell proliferation （BrdU） and cell differentiation （NeuN, APC, lbal, and S 100β）, respectively. Results The number of BrdU labeled cells decreased significantly with the development of the brain. Cell proliferation was prominent in the cortex and striatum. A small portion of BrdU and NeuN double labeled cells could be detected in the cortex at the early stage of development, and in the striatum and CA of the hippocampus in all groups. The majority of BrdU labeled cells were neuroglia, and the number of neuroglia cells decreased dramatically with brain maturation. Neurogenesis is the major cytogenesis in the dentate gyrus. Conclusion These results demonstrated that cell proliferation, differentiation and survival were age and brain region related.

Human umbilical cord-derived mesenchymal stem cells promote repair of neonatal brain injury caused by hypoxia/ischemia in rats

Administration of human umbilical cord-derived mesenchymal stem cells(hUC-MSCs)is believed to be an effective method for treating neurodevelopmental disorde rs.In this study,we investigated the possibility of hUC-MSCs treatment of neonatal hypoxic/ischemic brain injury associated with maternal immune activation and the underlying mechanism.We established neonatal rat models of hypoxic/ischemic brain injury by exposing pregnant rats to lipopolysaccharide on day 16 or 17 of pregnancy.Rat offspring were intranasally administe red hUC-MSCs on postnatal day 14.We found that polypyrimidine tract-binding protein-1(PTBP-1)participated in the regulation of lipopolysaccharide-induced maternal immune activation,which led to neonatal hypoxic/ischemic brain injury.Intranasal delive ry of hUC-MSCs inhibited PTBP-1 expression,alleviated neonatal brain injury-related inflammation,and regulated the number and function of glial fibrillary acidic protein-positive astrocytes,there by promoting plastic regeneration of neurons and im p roving brain function.These findings suggest that hUC-MSCs can effectively promote the repair of neonatal hypoxic/ischemic brain injury related to maternal immune activation through inhibition of PTBP-1 expression and astrocyte activation.

Physiological and pathological functions of circular RNAs in the nervous system

Circular RNAs(circRNAs)are a class of covalently closed single-stranded RNAs that are expressed during the development of specific cells and tissues.CircRNAs play crucial roles in physiological and pathological processes by sponging microRNAs,modulating gene transcription,controlling the activity of certain RNA-binding proteins,and producing functional peptides.A key focus of research at present is the functionality of circRNAs in the nervous system and several advances have emerged over the last 2 years.However,the precise role of circRNAs in the nervous system has yet to be comprehensively reviewed.In this review,we first summarize the recently described roles of circRNAs in brain development,maturity,and aging.Then,we focus on the involvement of circRNAs in various diseases of the central nervous system,such as brain cancer,chronic neurodegenerative diseases,acute injuries of the nervous system,and neuropathic pain.A better understanding of the functionality of circRNAs will help us to develop potential diagnostic,prognostic,and therapeutic strategies to treat diseases of the nervous system.

Dynamic changes in DNA demethylation in the tree shrew (Tupaia belangeri chinensis) brain during postnatal development and aging

Brain development and aging are associated with alterations in multiple epigenetic systems, including DNA methylation and demethylation patterns. Here, we observed that the levels of the 5- hydroxymethylcytosine （5hmC） ten-eleven transtocation （TET） enzyme-mediated active DNA demethylation products were dynamically changed and involved in postnatal brain development and aging in tree shrews （Tupaia belangeri chinensis）. The levels of 5hmC in multiple anatomic structures showed a gradual increase throughout postnatal development, whereas a significant decrease in 5hmC was found in several brain regions in aged tree shrews, including in the prefrontal cortex and hippocampus, but not the cerebellum. Active changes in Tet mRNA levels indicated that TET2 and TET3 predominantly contributed to the changes in 5hmC levels. Our findings provide new insight into the dynamic changes in 5hmC levels in tree shrew brains during postnatal development and aging processes.

Impact of SARS-CoV-2 infection during pregnancy on postnatal brain development:The potential role of glial cells

Glial cells are crucial for maintaining central nervous system(CNS)homeostasis.They actively participate in immune responses,as well as form functional barriers,such as blood-brain barrier(BBB),which restrict the entry of pathogens and inflammatory mediators into the CNS.In general,viral infections during the gestational period can alter the embryonic and fetal environment,and the related inflammatory response may affect neurodevelopment and lead to behavioral dysfunction during later stage of life,as highlighted by our group for Zika virus infection.Severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)induces a cytokine storm and,during pregnancy,may be related to a more severe form of the coronavirus disease-19(COVID-19)and also to higher preterm birth rates.SARS-CoV-2 can also affect the CNS by inducing neurochemical remodeling in neural cells,which can compromise neuronal plasticity and synaptic function.However,the impact of SARS-CoV-2 infection during pregnancy on postnatal CNS,including brain development during childhood and adulthood,remains undetermined.Our group has recently highlighted the impact of COVID-19 on the expression of molecular markers associated with neuropsychiatric disorders,which are strongly related to the inflammatory response.Thus,based on these relationships,we discussed the impact of SARS-CoV-2 infection either during pregnancy or in critical periods of neurodevelopment as a risk factor for neurological consequences in the offspring later in life,focusing on the potential role of glial cells.Thus,it is important to consider future and long-term public health concerns associated with SARS-CoV-2 infection during pregnancy.

The changes of oligodendrocytes induced by anesthesia during brain development

With the advent of modern techniques, drugs, and monitoring, general anesthesia has come to be considered an unlikely cause of harm, particularly for healthy patients. While this is largely true, newly emerging clinical and laboratory studies have sug- gested that exposure to anesthetic agents during early childhood may have long-lasting adverse effects on cognitive function. This concern has been the focus of intense study in the field of anesthesia research. A recent high-profile review by Rappaport et al. （2015） concluded that while many questions remain un- answered, there is strong evidence from laboratory studies that commonly used anesthetics interfere with brain development and that clinical studies suggest a correlation between early childhood exposure to these agents and subsequent effects on learning and cognition. The issue is of sufficient public health importance that a public-private partnership known as Smar- Tots （Strategies for Mitigating Anesthesia-Related Neurotoxicity in Tots） was developed by the FDA to study pediatric anesthetic neurotoxicity. The mechanism of injury underlying this phe- nomenon has yet to be fully elucidated, and there is evidence to suggest that anesthetics may have direct cytotoxic effects on neurons leading to cell death or suppressed neurogenesis （Strat- mann et al., 2010） and that they may interfere with key pro- cesses in neuronal growth and development that underlie brain circuit development （Wagner et al., 2014）.

Microglial dynamics during brain development

Microglia are the resident immune cells of the central nervous system （CNS）, In the normal state, microglia have a ramified shape and con- tinuously survey the conditions of the brain.

Omega-6 for Body,Omega-3 for Brain:Balance for Brain Development in Children

Food must supply a balance of nutrients to support both brain and body.The human brain makes us uniquely human.Essential fatty acids are part of the metabolic pathways that define tissue structure and function.Omega-6(O6)linoleic acid(LA6)has long been known to be required for skin structure,and as a precursor for inflammatory,thrombotic,immune,and other signaling molecules.Omega-3(O3)alpha-linolenic acid(ALA3)and particularly its long chain product docosahexaenoic acid(DHA3)has a key structural role in the brain,retina,and related neural tissue.In the 20 th century western world,inexpensive,high quality oils primarily from LA6-rich/O3-poor vegetable seed oils became dominant fats produced by the food industry.Provision of LA6-rich/O3-poor oils as the sole source of fat in the diets of pregnant animals causes O3 deficiency and poor brain development,primarily because high LA6 antagonizes metabolism of all O3,creating an artificial metabolic demand for O3.Data developed over the last 2~3 decades show that provision of low LA6 combined with preformed DHA3 optimizes brain function.Recent studies emphasize the importance of nutrition to support brain development,with newer findings showing particular importance of fatty acid balance in malnourished children.The World Health Organization(WHO)through the Codex Alimentarius(“Code for Food”)is increasingly recognizing the primacy of brain health and in part on that basis recently acted to recommend balanced fat for Ready-to-Use-Therapeutic Foods used to treat children with severe acute malnutrition.Similar principles are likely to be important in older persons.Industry now has the tools to adjust the composition of oils to support brain health throughout the life cycle.

Basic Research on Brain Development and Neural Plasticity Kicked Off

A major basic research projectin the field of neurosciencewas launched on November26 last year at the Shanghai-basedInstitute of Neuroscience of the Chi-nese Academy of Sciences(CAS).

Molecular neuro-oncology and development of targeted therapeutic strategies for brain tumors

Brain tumors are a diverse group of malignancies that remain refractory to conventional treatment approaches.Molecular neuro-oncologyhas now begun to clarify the transformed phenotype of brain tumors and identify oncogenic pathways that might be amenable to targetedtherapy.Activity of the phosphoinositide 3;kinase(PI3K)/Akt pathway is often upregulated in brain tumors due to excessive stimu-lation by growth factor receptors and Ras.Loss of function of the tumor suppressor gene PTEN also frequently contributesto

Tetrabromobisphenol A exerts thyroid disrupting effects but has little overt impact on postnatal brain development and neurobehaviors in mice

Tetrabromobisphenol A(TBBPA)is a widely used brominated flame retardant.There is evidence showing that TBBPA can exert thyroid disrupting effects in mammals,but different results were also reported,along with inconsistent reports regarding its neurotoxicity.Here,we investigated thyroid disrupting effects and neurotoxicity of TBBPA(5,50,500μg/(kg·day))to male mice following maternal and direct exposure through drinking water,with the antithyroid drug propylthiouracil(PTU)as the positive control.On postnatal day(PND)15,we expectedly observed severe thyroid compensatory hyperplasia and cerebellar developmental retardation in PTU-treated pups.The highest dose of TBBPA also caused thyroid histological alteration but had no effects on cerebellar development in terms of Purkinje cell morphology and the thickness of the internal granular layer and the molecular layer of the cerebellum.During puberty and adulthood,the thyroid morphological alterations became more pronounced in the TBBPA-treated animals,accompanied by decreased serum thyroid hormone levels.Furthermore,the 50 and 500μg/(kg·day)TBBPA groups showed a significant decrease in the serum level of serotonin,a neurotransmitter associated with anxiety behaviors.Correspondingly,the highest dose group displayed anxiety-like behaviors in the elevated plus-maze test on PND 35,but this neurobehavioral alteration disappeared on PND 56.Moreover,no changes in neurobehavioral parameters tested were found in TBBPAtreated animals at puberty and adulthood.Altogether,all observations show that TBBPA can exert thyroid disrupting effects but has little overt impact on brain development and neurobehaviors in mice,suggesting that thyroid disruption does not necessarily cause overtly adverse neurodevelopmental outcomes.

Genomic Mosaicism of the Brain:Origin,Impact,and Utility

Genomic mosaicism describes the phenomenon where some but not all cells within a tissue harbor unique genetic mutations.Traditionally,research focused on the impact of genomic mosaicism on clinical phenotype—motivated by its involvement in cancers and overgrowth syndromes.More recently,we increasingly shifted towards the plethora of neutral mosaic variants that can act as recorders of cellular lineage and environmental exposures.Here,we summarize the current state of the field of genomic mosaicism research with a special emphasis on our current understanding of this phenomenon in brain development and homeostasis.Although the field of genomic mosaicism has a rich history,technological advances in the last decade have changed our approaches and greatly improved our knowledge.We will provide current definitions and an overview of contemporary detection approaches for genomic mosaicism.Finally,we will discuss the impact and utility of genomic mosaicism.

Viruses and autism: A Bi-mutual cause and effect

Autism spectrum disorder(ASD)is a group of heterogeneous,multi-factorial,neurodevelopmental disorders resulting from genetic and environmental factors interplay.Infection is a significant trigger of autism,especially during the critical developmental period.There is a strong interplay between the viral infection as a trigger and a result of ASD.We aim to highlight the mutual relationship between autism and viruses.We performed a thorough literature review and included 158 research in this review.Most of the literature agreed on the possible effects of the viral infection during the critical period of development on the risk of developing autism,especially for specific viral infections such as Rubella,Cytomegalovirus,Herpes Simplex virus,Varicella Zoster Virus,Influenza virus,Zika virus,and severe acute respiratory syndrome coronavirus 2.Viral infection directly infects the brain,triggers immune activation,induces epigenetic changes,and raises the risks of having a child with autism.At the same time,there is some evidence of increased risk of infection,including viral infections in children with autism,due to lots of factors.There is an increased risk of developing autism with a specific viral infection during the early developmental period and an increased risk of viral infections in children with autism.In addition,children with autism are at increased risk of infection,including viruses.Every effort should be made to prevent maternal and early-life infections and reduce the risk of autism.Immune modulation of children with autism should be considered to reduce the risk of infection.

Temporal and spatial distribution of metabotropic glutamate receptor 5 during development in the rat cortex and hippocampus

Metabotropic glutamate receptor 5 （mGluR5） is expressed by neurons in zones of active neurogenesis and is involved in the development of neural stem cells in vivo and in vitro. We examined the expression of mGluR5 in the cortex and hippocampus of rats during various prenatal and postnatal periods using immunohistochemistry. During prenatal development, mGluR5 was pdmadly localized to neuronal somas in the forebrain. During early postnatal periods, the receptor was mainly present on somas in the cortex, mGluR5 immunostaining was visible in apical dendrites and in the neuropil of neurons and persisted throughout postnatal development. During this period, pyramidal neurons were strongly labeled for the receptor. In the hippocampal CA1 region, mGluR5 immunoreactivity was more intense in the stratum oriens, stratum radiatum, and lacunosum moleculare at P0, P5 and P10 relative to P60. mGluR5 expression increased significantly in the molecular layer and decreased significantly in the granule cell layer of the dentate gyrus at P5, P10 and P60 in comparison with P0. Furthermore, some mGluR5-positive cells were also bromodeoxyuridine- or NeuroD-positive in the dentate gyrus at P14. These results demonstrate that mGluR5 has a differential expression pattern in the cortex and hippocampus during early growth, suggesting a role for this receptor in the control of domain specific brain developmental events.

Advances and Applications of Brain Organoids

Understanding the fundamental processes of human brain development and diseases is of great importance for our health.However,existing research models such as non-human primate and mouse models remain limited due to their developmental discrepancies compared with humans.Over the past years,an emerging model,the“brain organoid”integrated from human pluripotent stem cells,has been developed to mimic developmental processes of the human brain and disease-associated phenotypes to some extent,making it possible to better understand the complex structures and functions of the human brain.In this review,we summarize recent advances in brain organoid technologies and their applications in brain development and diseases,including neurodevelopmental,neurodegenerative,psychiatric diseases,and brain tumors.Finally,we also discuss current limitations and the potential of brain organoids.

Overview of Attention Deficit Hyperactivity Disorder

This paper aims to provide an effective overview of ADHD(Attention Deficit Hyperactivity Disorder),so that educators and other individuals who may be involved in the treatment of ADHD patients,especially young patients,can effectively obtain basic information about what is ADHD,the causes of ADHD,and the popular treatment methods of ADHD.Various literature and studies were referred to in this paper to review and compare different causes and treatments.Researches held distinct opinions about the causes of ADHD,and the debate focuses on the nature and nurture factors of ADHD.Some studies believe ADHD is inborn and genetic while other studies emphasize the importance of nurture factors during their life,such as the environment that patients grow up in and the lifestyle they have.Depending on distinct arguments,there developed different treatments like using medication to prevent the situation from deteriorating further and changing the environments that patients living in through taking interventions with the family.These arguments and treatments will be discussed in detail in this paper.

Aberrant auditory system and its developmental implications for autism

Most infants who are later diagnosed with autism show delayed speech and language and/or atypical language profile.There is a large body of research on abnormal speech and language in children with autism.However,auditory development has been relatively under-investigated in autism research,despite its inextricable relationship with language development and despite researchers'ability to detect abnormalities in brain development and behavior in early infancy.In this review,we synthesize research on auditory processing in the prenatal period through infancy and childhood in typically developing children,children at high risk for autism,and children diagnosed with autism.We conclude that there are clear neurobiological and behavioral links between abnormal auditory development and the deficits in social communication seen in autism.We then offer perspectives on the need for a systematic characterization of early auditory development in autism,and identified questions to be addressed in future research on the development of autism.