Subplate neurons (SPNs) are among the earliest-born and most mature neurons in the developing cortex and are critical for thalamocortical axon pathfinding, radial migration, and early thalamocortical circuit formation. SPNs have been proposed to drive cortical folding, but their specific morphological features are not fully understood. This study examined SPN dendritic arborisation in two gyrencephalic species (sheep and ferret) before, during, and after the onset of primary folding, as well as at developmentally equivalent stages in the lissencephalic spiny mouse. Golgi-stained brains were analysed using Sholl analysis, along with additional metrics including number of primary branches, maximum intersections, path length, and skewness (branching asymmetry). Qualitative observations revealed region-specific differences in dendritic orientation and cell-type distribution between gyri and sulci in the gyrencephalic species, which were not found in the lissencephalic spiny mouse. MANOVA and two-way ANOVA with Bonferroni post-hoc tests showed no overall difference in SPNs arborisation throughout development in any species. Similarly, no differences were identified between gyral and sulcal SPNs in the ferret throughout gyrification, except for skewness in the sheep following the emergence of primary folds, where sulcal SPNs showed less branching away from the soma. These findings provide a valuable reference for future studies investigating SPNs and early cortical circuit formation in both gyrencephalic and lissencephalic brains. Further studies using advanced imaging and analytical methods may uncover more subtle region-specific differences in dendritic architecture and neuronal orientation.

INTRODUCTION:Birth asphyxia-induced encephalopathy is a major cause of long-term neurological morbidity, including cognitive and motor deficits. A proposed treatment is maternal creatine supplementation for prophylactic neuroprotection. This study examined how maternal creatine supplementation with or without birth asphyxia affected the behaviour of spiny mice offspring. METHODS:On day 20 of gestation (mid-gestation; term = 39 days), dams were randomly allocated to either a daily diet containing 5% w/w creatine monohydrate or remained on standard rodent chow. On gestational day 38, dams underwent either control caesarean section where offspring were delivered and recovered immediately, or birth asphyxia whereby the pregnant uterus was excised and placed in a saline bath for 7.5 min, inducing global hypoxia. All offspring were then cross-fostered to a lactating dam. Behavioural assessments were then completed on recovered offspring from neonatal to adolescent/adult ages (postnatal day [PND] 3-41) using the open-field, elevated plus maze, and novel object recognition test. RESULTS:Offspring that underwent birth asphyxia displayed locomotor deficits and increased anxiety-like behaviour at PND 3-7 in the open-field test (p < 0.05) and impaired novel object discrimination at PND 18 (p < 0.05). Antenatal creatine exposure reduced anxiety-like behaviour irrespective of asphyxia in pups at PND 3, indicating an amelioration of the asphyxia-induced anxiety-like behaviour. In adolescence/adulthood, creatine and asphyxia-exposed offspring showed reduced object exploration (p < 0.0001). Antenatal creatine led to sustained reductions in anxiety-like behaviour in the elevated plus maze at adolescence and increased body weight, regardless of birth asphyxia exposure (p < 0.05). CONCLUSION:Antenatal creatine exposure following maternal dietary creatine supplementation decreased anxiety-like behaviour in spiny mice offspring. This change negated behavioural abnormalities caused by birth asphyxia in the neonatal period, though it may have broader influences on long-term emotional and information processing in offspring which warrants further investigation.

Introduction: The ferret is an important model for studying corticogenesis and cortical gyrification due to its small size, condensed cortical development timeline, and postnatal onset of gyrification. Its cortical progenitor and neuronal diversity closely resemble those of humans. However, detailed histological data across the rostrocaudal axis at critical embryonic and postnatal stages remain limited, particularly for recently identified progenitor subpopulations. This study aimed to comprehensively characterise the spatiotemporal expression of key progenitor and neuronal markers throughout the rostrocaudal axis of the developing ferret cortex at critical embryonic and postnatal ages. In doing so, the study sought to establish a foundational, descriptive atlas of neurodevelopmental marker expression across key time points and cortical regions and layers. Methods: Immunofluorescent labelling of key neural progenitor and neuronal markers was performed on coronal ferret brain sections at embryonic (E34, E38) and postnatal (P2, P5, P15, P25) ages. Markers included PAX6, SOX2, TBR2, HOPX, CPLX3, CTIP2, SATB2, TUJ1, and DCX. Semi-quantitative analyses described the spatiotemporal distribution of each marker within defined cortical compartments along the rostrocaudal axis. Results: Early radial glial markers PAX6 and SOX2 were abundant in the ventricular zone at embryonic stages, progressively declining postnatally as the subventricular zone (SVZ) expanded. Intermediate progenitor cells labelled by TBR2 showed high abundance in the SVZ prenatally, with a marked decrease after birth. HOPX identified outer radial glia populations exhibiting distinct temporal and spatial distributions, with increasing presence in the subplate (SP) and cortical plate during postnatal stages. CPLX3 expression emerged postnatally, delineating mature SP neurons with regionally patterned maturation. Deep- and superficial-layer neuronal markers CTIP2 and SATB2 displayed orderly laminar emergence, indicating progressive cortical layer formation. General neuronal markers TUJ1 and DCX highlighted the maturation and migration of post-mitotic neurons, with spatiotemporal gradients reflecting cortical differentiation across regions. Conclusion: This detailed profiling fills critical gaps in the ferret histological record and serves as a valuable resource for investigations into mammalian corticogenesis using the ferret model. Through the integration of semi-quantitative assessments and qualitative analysis, this dataset contributes to the ongoing development of a detailed atlas of ferret brain development. These findings are expected to enhance the utility of the ferret model in neurodevelopmental research, particularly in translational contexts involving human cortical malformations.

OBJECTIVE:Hypoxic-ischemic encephalopathy (HIE) is a major cause of perinatal brain injury. Creatine is a dietary supplement that can increase intracellular phosphocreatine to improve the provision of intracellular adenosine triphosphate (ATP) to meet the increase in metabolic demand of oxygen deprivation. Here, we assessed prophylactic fetal creatine supplementation in reducing acute asphyxia-induced seizures, disordered electroencephalography (EEG) activity and cerebral inflammation and cell death histopathology. METHODS:Fetal sheep (118 ± 1 days' gestational age [dGA]; 0.8 gestation) were implanted with electrodes to continuously record EEG and nuchal electromyogram activity. At 121 dGA, fetuses were randomly assigned to sham control (i.v. saline infusion without umbilical cord occlusion [UCO]; SalCon), continuous i.v. creatine infusion (6 mg/kg/h; CrUCO) or isovolumetric saline (SalUCO) followed by UCO at 128 ± 2 dGA that lasted until the mean arterial blood pressure reached 19 mmHg. Brain tissue was collected for histopathology after 72 hours of recovery. RESULTS:Creatine supplementation had no effects on basal systemic or neurological physiology. UCO duration did not differ between CrUCO and SalUCO. After reperfusion, CrUCO fetuses had improved EEG power and frequency recovery and reduced electrographic seizure incidence (SalUCO, 86% vs CrUCO, 29%) and burden. At 72 hours after UCO, cell death in the cerebral cortex and astrogliosis in the periventricular white matter were reduced in CrUCO fetuses compared with SalUCO. INTERPRETATION:Creatine supplementation reduced post-asphyxial seizures and improved EEG recovery. Improvements in functional recovery with creatine were associated with regional reductions in cell death and astrogliosis. Prophylactic creatine treatment has the potential to mitigate functional indices of HIE in the late gestation fetal brain. ANN NEUROL 2025;97:673-687.

Intrauterine growth restriction (IUGR) is a pregnancy complication impairing fetal growth and development. The compromised development is often attributed to disruptions of oxygen and nutrient supply from the placenta, resulting in a number of unfavourable physiological outcomes with impaired brain and organ growth. IUGR is associated with compromised development of both grey and white matter, predisposing the infant to adverse neurodevelopmental outcomes, including long-lasting cognitive and motor difficulties. Cerebral thyroid hormone (TH) signalling, which plays a crucial role in regulating white and grey matter development, is dysregulated in IUGR, potentially contributing to the neurodevelopmental delays associated with this condition. Notably, one of the major TH transporters, monocarboxylate transporter-8 (MCT8), is deficient in the fetal IUGR brain. Currently, no effective treatment to prevent or reverse IUGR exists. Management strategies involve close antenatal monitoring, management of maternal risk factors if present and early delivery if IUGR is found to be severe or worsening in utero. The overall goal is to determine the most appropriate time for delivery, balancing the risks of preterm birth with further fetal compromise due to IUGR. Drug candidates have shown either adverse effects or little to no benefits in this vulnerable population, urging further preclinical and clinical investigation to establish effective therapies. In this review, we discuss the major neuropathology of IUGR driven by uteroplacental insufficiency and the concomitant long-term neurobehavioural impairments in individuals born IUGR. Importantly, we review the existing clinical and preclinical literature on cerebral TH signalling deficits, particularly the impaired expression of MCT8 and their correlation with IUGR. Lastly, we discuss the current evidence on MCT8-independent TH analogues which mimic the brain actions of THs by being metabolised in a similar manner as promising, albeit underappreciated approaches to promote grey and white matter development and improve the neurobehavioural outcomes following IUGR.

Accurate detection of hypoxia during fetal monitoring is critical for timely intervention and prevention of brain injury. This study investigated hypoxia detection in fetal sheep by developing a classifier to differentiate between baseline, during acute hypoxia (umbilical cord occlusion; UCO), and post-hypoxia recovery (post-UCO), using physiological signals and an XGBoost machine learning model. A multi-modal approach integrating electrocardiogram (ECG), electroencephalogram (EEG), and electromyogram (EMG) signals was compared to a model based on the ECG signal only. We included recordings from 14 fetal sheep, each of which underwent acute hypoxia via a single UCO procedure. Performance of hypoxia detection was measured by Marco F1 score (F1 m ), Accuracy (Acc), and standard deviation of validation error (SDE). Our multi-modal model achieved F1 m = 0.88, Acc = 0.90, while the ECG-based approach achieved F1 m = 0.82, Acc = 0.85. These results indicate that the multi-modal approach was superior to the ECG-only model for overall classification. While ECG and multimodal models correctly classified over 92% and 97% of acute hypoxia intervals, respectively, the classification of post- UCO intervals proved more challenging. The complexity of interpreting physiological signals underscores the need to consider temporal dynamics and physiological context in fetal monitoring.

The actin cytoskeleton is a key determinant of cell and tissue homeostasis. However, tissue-specific roles for actin dynamics in aging, notably brain aging, are not understood. Here, we show that there is an age-related increase in filamentous actin (F-actin) in Drosophila brains, which is counteracted by prolongevity interventions. Critically, modulating F-actin levels in aging neurons prevents age-onset cognitive decline and extends organismal healthspan. Mechanistically, we show that autophagy, a recycling process required for neuronal homeostasis, is disabled upon actin dysregulation in the aged brain. Remarkably, disrupting actin polymerization in aged animals with cytoskeletal drugs restores brain autophagy to youthful levels and reverses cellular hallmarks of brain aging. Finally, reducing F-actin levels in aging neurons slows brain aging and promotes healthspan in an autophagy-dependent manner. Our data identify excess actin polymerization as a hallmark of brain aging, which can be targeted to reverse brain aging phenotypes and prolong healthspan.

The dynamin-related guanosine triphosphatase, Drp1 (encoded by Dnm1l ), plays a central role in mitochondrial fission and is requisite for numerous cellular processes; however, its role in muscle metabolism remains unclear. Here, we show that, among human tissues, the highest number of gene correlations with DNM1L is in skeletal muscle. Knockdown of Drp1 (Drp1-KD) promoted mitochondrial hyperfusion in the muscle of male mice. Reduced fatty acid oxidation and impaired insulin action along with increased muscle succinate was observed in Drp1-KD muscle. Muscle Drp1-KD reduced complex II assembly and activity as a consequence of diminished mitochondrial translocation of succinate dehydrogenase assembly factor 2 (Sdhaf2). Restoration of Sdhaf2 normalized complex II activity, lipid oxidation, and insulin action in Drp1-KD myocytes. Drp1 is critical in maintaining mitochondrial complex II assembly, lipid oxidation, and insulin sensitivity, suggesting a mechanistic link between mitochondrial morphology and skeletal muscle metabolism, which is clinically relevant in combatting metabolic-related diseases.

Abstract Background Intrauterine inflammation is considered a major cause of brain injury in preterm infants, leading to long-term neurodevelopmental deficits. A potential contributor to this brain injury is dysregulation of neurovascular coupling. We have shown that intrauterine inflammation induced by intra-amniotic lipopolysaccharide (LPS) in preterm lambs, and postnatal dopamine administration, disrupts neurovascular coupling and the functional cerebral haemodynamic responses, potentially leading to impaired brain development. In this study, we aimed to characterise the structural changes of the neurovascular unit following intrauterine LPS exposure and postnatal dopamine administration in the brain of preterm lambs using cellular and molecular analyses. Methods At 119–120 days of gestation (term = 147 days), LPS was administered into the amniotic sac in pregnant ewes. At 126-7 days of gestation, the LPS-exposed lambs were delivered, ventilated and given either a continuous intravenous infusion of dopamine at 10 µg/kg/min or isovolumetric vehicle solution for 90 min (LPS, n = 6; LPSDA, n = 6). Control preterm lambs not exposed to LPS were also administered vehicle or dopamine (CTL, n = 9; CTLDA, n = 7). Post-mortem brain tissue was collected 3–4 h after birth for immunohistochemistry and RT-qPCR analysis of components of the neurovascular unit. Results LPS exposure increased vascular leakage in the presence of increased vascular density and remodelling with increased astrocyte “end feet” vessel coverage, together with downregulated mRNA levels of the tight junction proteins Claudin-1 and Occludin. Dopamine administration decreased vessel density and size, decreased endothelial glucose transporter, reduced neuronal dendritic coverage, increased cell proliferation within vessel walls, and increased pericyte vascular coverage particularly within the cortical and deep grey matter. Dopamine also downregulated VEGFA and Occludin tight junction mRNA, and upregulated dopamine receptor DRD1 and oxidative protein (NOX1, SOD3) mRNA levels. Dopamine administration following LPS exposure did not exacerbate any effects induced by LPS. Conclusion LPS exposure and dopamine administration independently alters the neurovascular unit in the preterm brain. Alterations to the neurovascular unit may predispose the developing brain to further injury.

Fetal growth restriction (FGR) is a complex obstetric issue describing a fetus that does not reach its genetic growth potential. The primary cause of FGR is placental dysfunction resulting in chronic fetal hypoxaemia, which in turn causes altered neurological, cardiovascular and respiratory development, some of which may be pathophysiological, particularly for neonatal life. The brainstem is the critical site of cardiovascular, respiratory and autonomic control, but there is little information describing how chronic hypoxaemia and the resulting FGR may affect brainstem neurodevelopment. This review provides an overview of the brainstem-specific consequences of acute and chronic hypoxia, and what is known in FGR. In addition, we discuss how brainstem structural alterations may impair functional control of the cardiovascular and respiratory systems. Finally, we highlight the clinical and translational findings of the potential roles of the brainstem in maintaining cardiorespiratory adaptation in the transition from fetal to neonatal life under normal conditions and in response to the pathological environment that arises during development in growth-restricted infants. This review emphasises the crucial role that the brainstem plays in mediating cardiovascular and respiratory responses during fetal and neonatal life. We assess whether chronic fetal hypoxaemia might alter structure and function of the brainstem, but this also serves to highlight knowledge gaps regarding FGR and brainstem development.

This document describes algorithms for generating general Morton and Hilbert orderings for three-dimensional data volumes.

This paper presents algorithms and pseudocode for encoding and decoding 3D Hilbert orderings.

ABSTRACT A major challenge in the biology of aging is to understand how specific age-onset pathologies relate to the overall health of the organism. The integrity of the intestinal epithelium is essential for the wellbeing of the organism throughout life. In recent years, intestinal barrier dysfunction has emerged as an evolutionarily conserved feature of aged organisms, as reported in worms, flies, fish, rodents and primates. Moreover, age-onset intestinal barrier dysfunction has been linked to microbial alterations, elevated immune responses, metabolic alterations, systemic health decline and mortality. Here, we provide an overview of these findings. We discuss early work in the Drosophila model that sets the stage for examining the relationship between intestinal barrier integrity and systemic aging, then delve into research in other organisms. An emerging concept, supported by studies in both Drosophila and mice, is that directly targeting intestinal barrier integrity is sufficient to promote longevity. A better understanding of the causes and consequences of age-onset intestinal barrier dysfunction has significant relevance to the development of interventions to promote healthy aging.

Modern computer systems are characterized by deep memory hierarchies, composed of main memory, multiple layers of cache, and other specialized types of memory. In parallel and distributed systems, additional memory layers are added to this hierarchy. Achieving good performance for computational science applications, in terms of execution time, depends on the efficient use of this diverse and hierarchical memory. This paper revisits the use of space-filling curves to specify the ordering in memory of data structures used in representative scientific applications executing on parallel machines containing clusters of multicore CPUs with attached GPUs. This work examines the hypothesis that space-filling curves, such as Hilbert and Morton ordering, can improve data locality and hence result in more efficient data movement than row or column-based orderings. First, performance results are presented that show for what application parameterizations and machine characteristics this is the case, and are interpreted in terms of how an application interacts with the computer hardware and low-level software. This research particularly focuses on the use of stencil-based applications that form the basis of many scientific computations. Second, how space-filling curves impact data sharing in nearest-neighbour and stencil-based codes is considered.

BackgroundCreatine supplementation during pregnancy is a promising prophylactic treatment for perinatal hypoxic brain injury. Previously, in near-term sheep we have shown that fetal creatine supplementation reduces cerebral metabolic and oxidative stress induced by acute global hypoxia. This study investigated the effects of acute hypoxia with or without fetal creatine supplementation on neuropathology in multiple brain regions.MethodsNear-term fetal sheep were administered continuous intravenous infusion of either creatine (6 mg kg–1 h–1) or isovolumetric saline from 122 to 134 days gestational age (dGA; term is approx. 145 dGA). At 131 dGA, global hypoxia was induced by a 10 min umbilical cord occlusion (UCO). Fetuses were then recovered for 72 h at which time (134 dGA) cerebral tissue was collected for either RT-qPCR or immunohistochemistry analyses.ResultsUCO resulted in mild injury to the cortical gray matter, thalamus and hippocampus, with increased cell death and astrogliosis and downregulation of genes involved in regulating injury responses, vasculature development and mitochondrial integrity. Creatine supplementation reduced astrogliosis within the corpus callosum but did not ameliorate any other gene expression or histopathological changes induced by hypoxia. Of importance, effects of creatine supplementation on gene expression irrespective of hypoxia, including increased expression of anti-apoptotic (BCL-2) and pro-inflammatory (e.g., MPO, TNFa, IL-6, IL-1β) genes, particularly in the gray matter, hippocampus, and striatum were identified. Creatine treatment also effected oligodendrocyte maturation and myelination in white matter regions.ConclusionWhile supplementation did not rescue mild neuropathology caused by UCO, creatine did result in gene expression changes that may influence in utero cerebral development.

Fetal growth restriction (FGR) is associated with cardiovascular and respiratory complications after birth and beyond. Despite research showing a range of neurological changes following FGR, little is known about how FGR affects the brainstem cardiorespiratory control centres. The primary neurons that release serotonin reside in the brainstem cardiorespiratory control centres and may be affected by FGR. At two time points in the last trimester of sheep brain development, 110 and 127 days of gestation (0.74 and 0.86 of gestation), we assessed histopathological alterations in the brainstem cardiorespiratory control centres of the pons and medulla in early-onset FGR versus control fetal sheep. The FGR cohort were hypoxaemic and asymmetrically growth restricted. Compared to the controls, the brainstem of FGR fetuses exhibited signs of neuropathology, including elevated cell death and reduced cell proliferation, grey and white matter deficits, and evidence of oxidative stress and neuroinflammation. FGR brainstem pathology was predominantly observed in the medullary raphé nuclei, hypoglossal nucleus, nucleus ambiguous, solitary tract and nucleus of the solitary tract. The FGR groups showed imbalanced brainstem serotonin and serotonin 1A receptor abundance in the medullary raphé nuclei, despite evidence of increased serotonin staining within vascular regions of placentomes collected from FGR fetuses. Our findings demonstrate both early and adaptive brainstem neuropathology in response to placental insufficiency. KEY POINTS: Early-onset fetal growth restriction (FGR) was induced in fetal sheep, resulting in chronic fetal hypoxaemia. Growth-restricted fetuses exhibit persistent neuropathology in brainstem nuclei, characterised by disrupted cell proliferation and reduced neuronal cell number within critical centres responsible for the regulation of cardiovascular and respiratory functions. Elevated brainstem inflammation and oxidative stress suggest potential mechanisms contributing to the observed neuropathological changes. Both placental and brainstem levels of 5-HT were found to be impaired following FGR.

RNA editing, the endogenous modification of nucleic acids, is known to be altered in genes with important neurological function in schizophrenia (SCZ). However, the global profile and molecular functions of disease-associated RNA editing remain unclear. Here, we analyzed RNA editing in postmortem brains of four SCZ cohorts and uncovered a significant and reproducible trend of hypoediting in patients of European descent. We report a set of SCZ-associated editing sites via WGCNA analysis, shared across cohorts. Using massively parallel reporter assays and bioinformatic analyses, we observed that differential 3' untranslated region (3'UTR) editing sites affecting host gene expression were enriched for mitochondrial processes. Furthermore, we characterized the impact of two recoding sites in the mitofusin 1 (MFN1) gene and showed their functional relevance to mitochondrial fusion and cellular apoptosis. Our study reveals a global reduction of editing in SCZ and a compelling link between editing and mitochondrial function in the disease.

Background: A correct balance of activity of the GABA and glutamate systems is vital for optimal neurodevelopment and general CNS function, and the dysregulation of this balance has been implicated in a number of neurological conditions. Maternal exposure to stressors is known to have long lasting, deleterious impacts on neurobehaviour, and similarly, results in dysregulation of inhibitory and excitatory pathways in the offspring. The current study aimed to examine effects on these pathways in a guinea pig model of prenatal stress and to elucidate whether increased neuroprotective support by postnatal neurosteroid supplementation would ameliorate adverse outcomes. Methods: Prenatal stress was achieved by exposing pregnant guinea pigs dams to a strobe light for 2hrs/day on gestational age (GA) 50, 55, 60 and 65. Dams were allowed to spontaneously deliver (similar to GA70) and pups were orally administered either allopregnanolone analogue, ganaxolone (5 mg/kg/day in 45% cyclodextrin), the translocator protein (TSPO) agonist, emapunil (XBD173; 0.3 mg/kg/day in 1% tragacanth gum) or vehicle on postnatal days (PND) 1-7. Hippocampal samples were collected at PND30 to measure relative mRNA expression of components involved in the inhibitory GABAergic pathway and exctitatory glutamatergic pathway by realtime PCR. GABAergic interneurons were quantified by assessing immunohistochemical protein expression of markers parvalbumin, calbindin and calretinin. Results: mRNA expression of GABAergic pathway components at one week of age indicated immature expression profiles of the GABAA receptors as well as decreased GABA synthesis and transport suggesting reduced extrasynaptically-mediated tonic inhibition. Expression profiles of the pathways examined evolved between one week and one month of age but an imbalance in inhibitory/excitatory components persisted. The allopregnanolone analogue ganaxolone offered some protection against excitotoxicity in female hippocampus, however neurosteroid supplementation with ganaxolone or emapunil were unable to fully correct the GABAergic/glutamatergic imbalance observed following prenatal stress. Conclusion: Prenatal stress leads to programmed lasting effects on the major inhibitory and excitatory pathways in the guinea pig brain that continue evolving between the equivalent of early and late childhood. Neurosteroid therapies particularly improved outcomes in females. Further studies are required to identify additional therapeutic targets that are able to fully restore imbalances in the excitatory and inhibitory systems, which may act to prevent development of childhood behavioural disorders.