The impact of light during the night

Exposing chicks to one hour of light during the night disrupts the release of a hormone that is needed by cells in the developing brain to survive.

NEXMIF/KIDLIA Knock-out Mouse Demonstrates Autism-Like Behaviors, Memory Deficits, and Impairments in Synapse Formation and Function

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disability that demonstrates impaired social interactions, communication deficits, and restrictive and repetitive behaviors. ASD has a strong genetic basis and many ASD-associated genes have been discovered thus far. Our previous work has shown that loss of expression of the X-linked gene NEXMIF/KIDLIA is implicated in patients with autistic features and intellectual disability (ID). To further determine the causal role of the gene in the disorder, and to understand the cellular and molecular mechanisms underlying the pathology, we have generated a NEXMIF knock-out (KO) mouse. We find that male NEXMIF KO mice demonstrate reduced sociability and communication, elevated repetitive grooming behavior, and deficits in learning and memory. Loss of NEXMIF/KIDLIA expression results in a significant decrease in synapse density and synaptic protein expression. Consistently, male KO animals show aberrant synaptic function as measured by excitatory miniatures and postsynaptic currents in the hippocampus. These findings indicate that NEXMIF KO mice recapitulate the phenotypes of the human disorder. The NEXMIF KO mouse model will be a valuable tool for studying the complex mechanisms involved in ASD and for the development of novel therapeutics for this disorder.SIGNIFICANCE STATEMENT Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder characterized by behavioral phenotypes. Based on our previous work, which indicated the loss of NEXMIF/KIDLIA was associated with ASD, we generated NEXMIF knock-out (KO) mice. The NEXMIF KO mice demonstrate autism-like behaviors including deficits in social interaction, increased repetitive self-grooming, and impairments in communication and in learning and memory. The KO neurons show reduced synapse density and a suppression in synaptic transmission, indicating a role for NEXMIF in regulating synapse development and function. The NEXMIF KO mouse faithfully recapitulates the human disorder, and thus serves as an animal model for future investigation of the NEXMIF-dependent neurodevelopmental disorders.

Microglia and sexual differentiation of the developing brain: A focus on extrinsic factors

Microglia, the innate immune cells of the brain, have recently been removed from the position of mere sentinels and promoted to the role of active sculptors of developing circuits and cells. Alongside their functions in normal brain development, microglia coordinate sexual differentiation of the brain, a set of processes which vary by region and endpoint like that of microglia function itself. In this review, we highlight the ways microglia are both targets and drivers of brain sexual differentiation. We examine the factors that may drive sex differences in microglia, with a special focus on how changing microenvironments in the developing brain dictate microglia phenotypes and discuss how their diverse functions sculpt lasting sex-specific changes in the brain. Finally, we consider how sex-specific early life environments contribute to epigenetic programming and lasting sex differences in microglia identity.

Mutations in thyroid hormone receptor α1 cause premature neurogenesis and progenitor cell depletion in human cortical development

Mutations in the thyroid hormone receptor α 1 gene (THRA) have recently been identified as a cause of intellectual deficit in humans. Patients present with structural abnormalities including microencephaly, reduced cerebellar volume and decreased axonal density. Here, we show that directed differentiation of THRA mutant patient-derived induced pluripotent stem cells to forebrain neural progenitors is markedly reduced, but mutant progenitor cells can generate deep and upper cortical layer neurons and form functional neuronal networks. Quantitative lineage tracing shows that THRA mutation-containing progenitor cells exit the cell cycle prematurely, resulting in reduced clonal output. Using a micropatterned chip assay, we find that spatial self-organization of mutation-containing progenitor cells in vitro is impaired, consistent with down-regulated expression of cell-cell adhesion genes. These results reveal that thyroid hormone receptor α1 is required for normal neural progenitor cell proliferation in human cerebral cortical development. They also exemplify quantitative approaches for studying neurodevelopmental disorders using patient-derived cells in vitro.

Tubulin mutations in brain development disorders: Why haploinsufficiency does not explain TUBA1A tubulinopathies

The neuronal cytoskeleton performs incredible feats during nervous system development. Extension of neuronal processes, migration, and synapse formation rely on the proper regulation of microtubules. Mutations that disrupt the primary α-tubulin expressed during brain development, TUBA1A, are associated with a spectrum of human brain malformations. One model posits that TUBA1A mutations lead to a reduction in tubulin subunits available for microtubule polymerization, which represents a haploinsufficiency mechanism. We propose an alternative model for the majority of tubulinopathy mutations, in which the mutant tubulin polymerizes into the microtubule lattice to dominantly "poison" microtubule function. Nine distinct α-tubulin and ten β-tubulin genes have been identified in the human genome. These genes encode similar tubulin proteins, called isotypes. Multiple tubulin isotypes may partially compensate for heterozygous deletion of a tubulin gene, but may not overcome the disruption caused by missense mutations that dominantly alter microtubule function. Here, we describe disorders attributed to haploinsufficiency versus dominant negative mechanisms to demonstrate the hallmark features of each disorder. We summarize literature on mouse models that represent both knockout and point mutants in tubulin genes, with an emphasis on how these mutations might provide insight into the nature of tubulinopathy patient mutations. Finally, we present data from a panel of TUBA1A tubulinopathy mutations generated in yeast α-tubulin that demonstrate that α-tubulin mutants can incorporate into the microtubule network and support viability of yeast growth. This perspective on tubulinopathy mutations draws on previous studies and additional data to provide a fresh perspective on how TUBA1A mutations disrupt neurodevelopment.

Cortical developmental abnormalities in logopenic variant primary progressive aphasia with dyslexia

An increased prevalence of dyslexia has been observed in individuals diagnosed with primary progressive aphasia, most notably the logopenic variant primary progressive aphasia. The underlying pathology most commonly associated with logopenic variant primary progressive aphasia is Alzheimer's disease. In this clinical case report series, we describe the neuropathological findings of three patients with logopenic variant primary progressive aphasia and developmental dyslexia, each demonstrating a pattern of cerebrocortical microdysgenesis, reminiscent of findings first reported in dyslexic individuals, alongside expected Alzheimer's disease pathology. Neurodevelopmental and most severe Alzheimer's disease pathological changes overlapped within perisylvian brain regions, areas associated with phonological deficits in both logopenic variant primary progressive aphasia and dyslexia. These three cases with pathological findings support the hypothesis that early-life neurodevelopmental changes might influence later-life susceptibility to neurodegenerative disease and could contribute to non-amnestic, early age-of-onset presentations of Alzheimer's disease. Larger studies investigating neurobiological vulnerability across the lifespan are needed.

Optimal Assessment and Quantification of Iodine Nutrition in Pregnancy and Lactation: Laboratory and Clinical Methods, Controversies and Future Directions

Iodine intake must be boosted during pregnancy to meet the demands for increased production and placental transfer of thyroid hormone essential for optimal foetal development. Failure to meet this challenge results in irreversible brain damage, manifested in severity from neurological cretinism to minor or subtle deficits of intelligence and behavioural disorders. Attention is now being focused on explaining observational studies of an association between insufficient iodine intake during pregnancy and mild degrees of intellectual impairment in the offspring and confirming a cause and effect relationship with impaired maternal thyroid function. The current qualitative categorisation of iodine deficiency into mild, moderate and severe by the measurement of the median urinary iodine concentration (MUIC) in a population of school-age children, as a proxy measure of dietary iodine intake, is inappropriate for defining the degree or severity of gestational iodine deficiency and needs to be replaced. This review examines progress in analytical techniques for the measurement of urinary iodine concentration and the application of this technology to epidemiological studies of iodine deficiency with a focus on gestational iodine deficiency. We recommend that more precise definitions and measurements of gestational iodine deficiency, beyond a spot UIC, need to be developed. We review the evidence for hypothyroxinaemia as the cause of intrauterine foetal brain damage in gestational iodine deficiency and discuss the many unanswered questions, from which we propose that further clinical studies need to be designed to address the pathogenesis of neurodevelopmental impairments in the foetus and infant. Agreement on the testing instruments and standardization of processes and procedures for Intelligence Quotient (IQ) and psychomotor tests needs to be reached by investigators, so that valid comparisons can be made among studies of gestational iodine deficiency and neurocognitive outcomes. Finally, the timing, safety and the efficacy of prophylactic iodine supplementation for pregnant and lactating women needs to be established and confirmation that excess intake of iodine during pregnancy is to be avoided.

Altered Functional Brain Network Integration, Segregation, and Modularity in Infants Born Very Preterm at Term-Equivalent Age

OBJECTIVES

To determine the functional network organization of the brain in infants born very preterm at term-equivalent age and to relate network alterations to known clinical risk factors for poor neurologic outcomes in prematurity.

STUDY DESIGN

Resting-state functional magnetic resonance imaging data from 66 infants born very preterm (gestational age <32 weeks and birth weight <1500 g) and 66 healthy neonates born at full term, acquired as part of a prospective, cross-sectional study, were compared at term age using graph theory. Features of resting-state networks, including integration, segregation, and modularity, were derived from correlated hemodynamic activity arising from 93 cortical and subcortical regions of interest and compared between groups.

RESULTS

Despite preserved small-world topology and modular organization, resting-state networks of infants born very preterm at term-equivalent age were less segregated and less integrated than those of infants born full term. Chronic respiratory illness (ie, bronchopulmonary dysplasia and the length of oxygen support) was associated with decreased global efficiency and increased path lengths (P < .05). In both cohorts, 4 functional modules with similar composition were observed (parietal/temporal, frontal, subcortical/limbic, and occipital). The density of connections in 3 of the 4 modules was decreased in the very preterm network (P < .01); however, in the occipital/visual cortex module, connectivity was increased in infants born very preterm relative to control infants (P < .0001).

CONCLUSIONS

Early exposure to the ex utero environment is associated with altered resting-state network functional organization in infants born very preterm at term-equivalent age, likely reflecting disrupted brain maturational processes.

Cerebral hemodynamic responses in preterm-born neonates to visual stimulation: classification according to subgroups and analysis of frontotemporal-occipital functional connectivity

How neurovascular coupling develops in preterm-born neonates has been largely neglected in scientific research. We measured visually evoked (flicker light) hemodynamic responses (HRs) in preterm-born neonates ( n = 25 , gestational age: 31.71 ± 3.37 weeks, postnatal age: 25.48 ± 23.94 days) at the visual cortex (VC) and left frontotemporal lobe (FTL) using functional near-infrared spectroscopy (fNIRS) neuroimaging. We found that the HR characteristics show a large intersubject variability but could be classified into three groups according to the changes of oxyhemoglobin concentration at the VC [(A) increase, (B) decrease, or (C) inconclusive]. In groups A and B, the HRs at the left FTL were correlated with those at the VC, indicating the presence of a frontotemporal-occipital functional connectivity. Neonates in group A had a higher weight at measurement compared to those in group B, and had the lowest baseline total hemoglobin concentration and hematocrit compared to group C. To the best of our knowledge, this is the first fNIRS study showing (1) that the HRs of preterm-born neonates need to be classified into subgroups, (2) that the subgroups differed in terms of weight at measurement, and (3) that HRs can be observed also at the FTL during visual stimulation. These findings add insights into how neurovascular coupling develops in preterm-born neonates.

Building Bridges Between the Clinic and the Laboratory: A Meeting Review - Brain Malformations: A Roadmap for Future Research

In the middle of March 2019, a group of scientists and clinicians (as well as those who wear both hats) gathered in the green campus of the Weizmann Institute of Science to share recent scientific findings, to establish collaborations, and to discuss future directions for better diagnosis, etiology modeling and treatment of brain malformations. One hundred fifty scientists from twenty-two countries took part in this meeting. Thirty-eight talks were presented and as many as twenty-five posters were displayed. This review is aimed at presenting some of the highlights that the audience was exposed to during the three-day meeting.

Cortical Neurogenesis Requires Bcl6-Mediated Transcriptional Repression of Multiple Self-Renewal-Promoting Extrinsic Pathways

During neurogenesis, progenitors switch from self-renewal to differentiation through the interplay of intrinsic and extrinsic cues, but how these are integrated remains poorly understood. Here, we combine whole-genome transcriptional and epigenetic analyses with in vivo functional studies to demonstrate that Bcl6, a transcriptional repressor previously reported to promote cortical neurogenesis, acts as a driver of the neurogenic transition through direct silencing of a selective repertoire of genes belonging to multiple extrinsic pathways promoting self-renewal, most strikingly the Wnt pathway. At the molecular level, Bcl6 represses its targets through Sirt1 recruitment followed by histone deacetylation. Our data identify a molecular logic by which a single cell-intrinsic factor represses multiple extrinsic pathways that favor self-renewal, thereby ensuring robustness of neuronal fate transition.

Music-Evoked Reward and Emotion: Relative Strengths and Response to Intervention of People With ASD

This review presents research findings showing that music is a unique domain to assess perception, reward, emotion, and associated physiological reactions and neural circuitry of people with autism spectrum disorder (ASD). There is growing evidence, reported in several studies in this review article, indicating that music is a relative strength of people with ASD including musical pitch perception, musical memory, and identification of music-evoked emotions. Listening to music activates neural circuits of reward and emotion response, which are described. Research presented shows adults with ASD also activate these systems when listening to music, although there may be developmental differences in the physiological and neural response to music in childhood and adolescence alongside typical behavioral response. Nonetheless, studies reviewed lend support to the use of music therapy and education for people with ASD, specifically to improve social skills and communication. Neural correlates of response to music therapy and education are also discussed. Taken together, findings reviewed provide evidence for music as a strength-based approach for ASD to assess reward and emotion response and as a powerful tool for intervention.

Neuroanatomical distribution and functions of brain-derived neurotrophic factor in zebrafish (Danio rerio) brain

Brain-derived neurotrophic factor (BDNF) is an extensively studied protein that is evolutionarily conserved and widely distributed in the brain of vertebrates. It acts via its cognate receptors TrkB and p75^NTR and plays a central role in the developmental neurogenesis, neuronal survival, proliferation, differentiation, synaptic plasticity, learning and memory, adult hippocampal neurogenesis, and brain regeneration. BDNF has also been implicated in a plethora of neurological disorders. Hence, understanding the processes that are controlled by BDNF and their regulating mechanisms is important. Although, BDNF has been thoroughly studied in the mammalian models, contradictory effects of its functions have been reported on several occasions. These contradictory effects may be attributed to the sheer complexity of the mammalian brain. The study of BDNF and its associated functions in a simpler vertebrate model may provide some clarity about the effects of BDNF on the neurophysiology of the brain. Keeping that in mind, this review aims at summarizing the current knowledge about the distribution of BDNF and its associated functions in the zebrafish brain. The main focus of the review is to give a comparative overview of BDNF distribution and function in zebrafish and mammals with respect to distinct life stages. We have also reviewed the regulation of bdnf gene in zebrafish and discussed its role in developmental and adult neurogenesis.

Transcript Analysis of Zebrafish GLUT3 Genes, slc2a3a and slc2a3b, Define Overlapping as Well as Distinct Expression Domains in the Zebrafish (Danio rerio) Central Nervous System

The transport of glucose across the cell plasma membrane is vital to most mammalian cells. The glucose transporter (GLUT; also called SLC2A) family of transmembrane solute carriers is responsible for this function in vivo. GLUT proteins encompass 14 different isoforms in humans with different cell type-specific expression patterns and activities. Central to glucose utilization and delivery in the brain is the neuronally expressed GLUT3. Recent research has shown an involvement of GLUT3 genetic variation or altered expression in several different brain disorders, including Huntington's and Alzheimer's diseases. Furthermore, GLUT3 was identified as a potential risk gene for multiple psychiatric disorders. To study the role of GLUT3 in brain function and disease a more detailed knowledge of its expression in model organisms is needed. Zebrafish (Danio rerio) has in recent years gained popularity as a model organism for brain research and is now well-established for modeling psychiatric disorders. Here, we have analyzed the sequence of GLUT3 orthologs and identified two paralogous genes in the zebrafish, slc2a3a and slc2a3b. Interestingly, the Glut3b protein sequence contains a unique stretch of amino acids, which may be important for functional regulation. The slc2a3a transcript is detectable in the central nervous system including distinct cellular populations in telencephalon, diencephalon, mesencephalon and rhombencephalon at embryonic and larval stages. Conversely, the slc2a3b transcript shows a rather diffuse expression pattern at different embryonic stages and brain regions. Expression of slc2a3a is maintained in the adult brain and is found in the telencephalon, diencephalon, mesencephalon, cerebellum and medulla oblongata. The slc2a3b transcripts are present in overlapping as well as distinct regions compared to slc2a3a. Double in situ hybridizations were used to demonstrate that slc2a3a is expressed by some GABAergic neurons at embryonic stages. This detailed description of zebrafish slc2a3a and slc2a3b expression at developmental and adult stages paves the way for further investigations of normal GLUT3 function and its role in brain disorders.

Neurodevelopmental Trajectories Related to Attention Problems Predict Driving-Related Risk Behaviors

Objective: Investigate neurodevelopmental trajectories related to attention/hyperactivity problems (AP) in a community sample of adolescents and whether these trajectories predict later-emerging health risk behaviors. Method: One hundred sixty-six participants underwent up to three magnetic resonance imaging (MRI) scans (n = 367) between 11 and 20 years of age. AP were measured during early adolescence using the Child Behaviour Checklist, and engagement in risk behaviors was measured during late adolescence using the "DRIVE" survey (i.e., driving risks) and items assessing alcohol-harms. Results: Greater AP scores during early adolescence were related to less reduction over time of left dorsal prefrontal, left ventrolateral prefrontal, and right orbitofrontal thickness. Less thinning of the orbitofrontal cortex was related to greater driving-related risk behaviors at late adolescence. Conclusion: Findings highlight altered neurodevelopmental trajectories in adolescents with AP. Furthermore, altered orbitofrontal development was related to later-emerging driving-related risk, and this neurobiological change mediated the association between attention problems and risk behaviors.

Providing Supportive Hospital Environments to Promote the Language Development of Infants and Children Born Prematurely: Insights From Neuroscience

INTRODUCTION

Rapid neural development occurs beginning in utero and extending throughout a child's first years of life, shaped by environmental input, which is essential for language learning. If this development is disrupted by premature birth and/or related repeated hospitalizations, atypical language development may result even in the absence of severe neurologic damage.

METHOD

This narrative review describes typical neurodevelopment associated with language and the atypical neurodevelopment often experienced by children born prematurely that can adversely affect their language development.

RESULTS

We describe evidence-based intervention strategies applicable in the hospital setting that can support the language development of young children who are born prematurely.

DISCUSSION

To promote neurodevelopmental growth that will support language learning, children born prematurely need to engage in supportive interactions with others. Awareness of evidence-based strategies can equip health care staff to provide a supportive hospital environment to promote the language development of children born premature.

Robotic platform for microinjection into single cells in brain tissue

Microinjection into single cells in brain tissue is a powerful technique to study and manipulate neural stem cells. However, such microinjection requires expertise and is a low-throughput process. We developed the "Autoinjector", a robot that utilizes images from a microscope to guide a microinjection needle into tissue to deliver femtoliter volumes of liquids into single cells. The Autoinjector enables microinjection of hundreds of cells within a single organotypic slice, resulting in an overall yield that is an order of magnitude greater than manual microinjection. The Autoinjector successfully targets both apical progenitors (APs) and newborn neurons in the embryonic mouse and human fetal telencephalon. We used the Autoinjector to systematically study gap-junctional communication between neural progenitors in the embryonic mouse telencephalon and found that apical contact is a characteristic feature of the cells that are part of a gap junction-coupled cluster. The throughput and versatility of the Autoinjector will render microinjection an accessible high-performance single-cell manipulation technique and will provide a powerful new platform for performing single-cell analyses in tissue for bioengineering and biophysics applications.

FAM19A5 Expression During Embryogenesis and in the Adult Traumatic Brain of FAM19A5-LacZ Knock-in Mice

FAM19A5 is a secretory protein that is predominantly expressed in the brain. Although the FAM19A5 gene has been found to be associated with neurological and/or psychiatric diseases, only limited information is available on its function in the brain. Using FAM19A5-LacZ knock-in mice, we determined the expression pattern of FAM19A5 in developing and adult brains and identified cell types that express FAM19A5 in naïve and traumatic brain injury (TBI)–induced brains. According to X-gal staining results, FAM19A5 is expressed in the ventricular zone and ganglionic eminence at a very early stage of brain development, suggesting its functions are related to the generation of neural stem cells and oligodendrocyte precursor cells (OPCs). In the later stages of developing embryos and in adult mice, FAM19A5 expression expanded broadly to particular regions of the brain, including layers 2/3 and 5 of the cortex, cornu amonis (CA) region of the hippocampus, and the corpus callosum. X-gal staining combined with immunostaining for a variety of cell-type markers revealed that FAM19A5 is expressed in many different cell types, including neurons, OPCs, astrocytes, and microglia; however, only some populations of these cell types produce FAM19A5. In a subpopulation of neuronal cells, TBI led to increased X-gal staining that extended to the nucleus, marked by slightly condensed content and increased heterochromatin formation along the nuclear border. Similarly, nuclear extension of X-gal staining occurred in a subpopulation of OPCs in the corpus callosum of the TBI-induced brain. Together, these results suggest that FAM19A5 plays a role in nervous system development from an early stage and increases its expression in response to pathological conditions in subsets of neurons and OPCs of the adult brain.

Butylated Hydroxyanisole Exerts Neurotoxic Effects by Promoting Cytosolic Calcium Accumulation and Endoplasmic Reticulum Stress in Astrocytes

Astrocytes provide nutritional support, regulate inflammation, and perform synaptic functions in the human brain. Although butylated hydroxyanisole (BHA) is a well-known antioxidant, several studies in animals have indicated BHA-mediated liver toxicity, retardation in reproductive organ development and learning, and sleep deficit. However, the specific effects of BHA on human astrocytes and the underlying mechanisms are yet unclear. Here, we investigated the antigrowth effects of BHA through cell cycle arrest and downregulation of regulatory protein expression. The typical cell proliferative signaling pathways, phosphoinositide 3-kinase/protein kinase B and extracellular signal-regulated kinase 1/2, were downregulated in astrocytes after BHA treatment. BHA increased the levels of pro-apoptotic proteins, such as BAX, cytochrome c, cleaved caspase 3, and cleaved caspase 9, and decreased the level of anti-apoptotic protein BCL-XL. It also increased the cytosolic calcium level and the expression of endoplasmic reticulum stress proteins. Treatment with BAPTA-AM, a calcium chelator, attenuated the increased levels of ER stress proteins and cleaved members of the caspase family. We further performed an in vivo evaluation of the neurotoxic effect of BHA on zebrafish embryos and glial fibrillary acidic protein, a representative astrocyte biomarker, in a gfap:eGFP zebrafish transgenic model. Our results provide clear evidence of the potent cytotoxic effects of BHA on human astrocytes, which lead to disruption of the brain and nerve development.

Transgenic overexpression of polysialyltransferase ST8SiaIV under the control of a neuron-specific promoter does not affect brain development but impairs exploratory behavior

A large body of the literature has demonstrated that the polysialic acid (polySia) modification of the neural cell adhesion molecule (NCAM) is a key regulator of cellular interactions during brain development, maintenance and plasticity. To properly fulfill these functions, polySia concentration has to be carefully controlled. This is done by the regulation of the expression of the two polySia-synthesizing enzymes ST8SiaII and ST8SiaIV. From this point of view we and others have demonstrated that downregulation of ST8SiaIV during oligodendrocyte differentiation is a prerequisite for efficient myelin formation and maintenance. Here, we addressed the question whether the prevention of polySia downregulation in neurons affects brain and particularly myelin development and functioning. For this purpose, we developed transgenic (tg) mouse lines overexpressing the polysialyltransferase ST8SiaIV in neurons. tg expression of ST8SiaIV prevented the postnatal downregulation of polySia, and most of the polySias in the forebrain and brain stem of adult tg mice were associated with NCAM-140 and NCAM-180 isoforms. Structural examination of the brain revealed no overt abnormalities of axons and myelin. In addition, ultrastructural and western blot analyses indicated normal myelin development. However, behavioral studies revealed reduced rearing activity, a measure for exploratory behavior, while parameters of motor activity were not affected in tg mice. Taken together, these results suggest that a persisting presence of polySia in neurons has no major effect on brain structure, myelination and myelin maintenance, but causes mild behavioral changes.

Neural Encoding of Pitch Direction Is Enhanced in Musically Trained Children and Is Related to Reading Skills

Musical training in childhood has been linked to enhanced sound encoding at different stages of the auditory processing. In the current study, we used auditory event-related potentials to investigate cortical sound processing in 9- to 15-year-old children (N = 88) with and without musical training. Specifically, we recorded the mismatch negativity (MMN) and P3a responses in an oddball paradigm consisting of standard tone pairs with ascending pitch and deviant tone pairs with descending pitch. A subsample of the children (N = 44) also completed a standardized test of reading ability. The musically trained children showed a larger P3a response to the deviant sound pairs. Furthermore, the amplitude of the P3a correlated with a pseudo-word reading test score. These results corroborate previous findings on enhanced sound encoding in musically trained children and are in line with studies suggesting that neural discrimination of spectrotemporal sound patterns is predictive of reading ability.

Targeting Peripheral Somatosensory Neurons to Improve Tactile-Related Phenotypes in ASD Models

Somatosensory over-reactivity is common among patients with autism spectrum disorders (ASDs) and is hypothesized to contribute to core ASD behaviors. However, effective treatments for sensory over-reactivity and ASDs are lacking. We found distinct somatosensory neuron pathophysiological mechanisms underlie tactile abnormalities in different ASD mouse models and contribute to some ASD-related behaviors. Developmental loss of ASD-associated genes Shank3 or Mecp2 in peripheral mechanosensory neurons leads to region-specific brain abnormalities, revealing links between developmental somatosensory over-reactivity and the genesis of aberrant behaviors. Moreover, acute treatment with a peripherally restricted GABAA receptor agonist that acts directly on mechanosensory neurons reduced tactile over-reactivity in six distinct ASD models. Chronic treatment of Mecp2 and Shank3 mutant mice improved body condition, some brain abnormalities, anxiety-like behaviors, and some social impairments but not memory impairments, motor deficits, or overgrooming. Our findings reveal a potential therapeutic strategy targeting peripheral mechanosensory neurons to treat tactile over-reactivity and select ASD-related behaviors.

Sphingomyelin in Brain and Cognitive Development: Preliminary Data

Sphingomyelin (SM) supports brain myelination, a process closely associated with cognitive maturation. The presence of SM in breast milk suggests a role in infant nutrition; however, little is known about SM contribution to healthy cognitive development. We investigated the link between early life dietary SM, later cognitive development and myelination using an exploratory observational study of neurotypical children. SM levels were quantified in infant nutrition products fed in the first three months of life and associated with myelin content (brain MRI) as well as cognitive development (Mullen scales of early learning; MSEL). Higher levels of SM were significantly associated with higher rates of change in verbal development in the first two years of life (r = 0.65, p < 0.001), as well as, higher levels of myelin content at 12–24 months, delayed onset and/or more prolonged rates of myelination in different brain areas. Second, we explored mechanisms of action using in vitro models (Sprague Dawley rat pups). In vitro data showed SM treatment resulted in increased proliferation [p = 0.0133 and p = 0.0434 at 4 and 10 d in vitro (DIV)], maturation (p = 0.467 at 4 d DIV) and differentiation (p = 0.0123 and p = 0.0369 at 4 and 10 DIV) of oligodendrocyte precursor cells (OPCs), as well as increased axon myelination (p = 0.0005 at 32 DIV). These findings indicate an impact of dietary SM on cognitive development in healthy children, potentially modulated by oligodendrocytes and increased axon myelination. Future research should include randomized controlled trials to substantiate efficacy of SM for cognitive benefits together with preclinical studies examining SM bioavailability and brain uptake.

Sox1a mediates the ability of the parapineal to impart habenular left-right asymmetry

Left-right asymmetries in the zebrafish habenular nuclei are dependent upon the formation of the parapineal, a unilateral group of neurons that arise from the medially positioned pineal complex. In this study, we show that both the left and right habenula are competent to adopt left-type molecular character and efferent connectivity upon the presence of only a few parapineal cells. This ability to impart left-sided character is lost in parapineal cells lacking Sox1a function, despite the normal specification of the parapineal itself. Precisely timed laser ablation experiments demonstrate that the parapineal influences neurogenesis in the left habenula at early developmental stages as well as neurotransmitter phenotype and efferent connectivity during subsequent stages of habenular differentiation. These results reveal a tight coordination between the formation of the unilateral parapineal nucleus and emergence of asymmetric habenulae, ensuring that appropriate lateralised character is propagated within left and right-sided circuitry.