DEVELOPMENTAL NEUROSCIENCE

Ultrarare Variants in DNA Damage Repair Genes in Pediatric Acute-Onset Neuropsychiatric Syndrome or Acute Behavioral Regression in Neurodevelopmental Disorders
Cunningham JL, Frankovich J, Dubin RA, Pedrosa E, Baykara RN, Schlenk NC, Maqbool SB, Dolstra H, Marino J, Edinger J, Shea JM, Laje G, Swagemakers SMA, Sinnadurai S, Zhang ZD, Lin JR, van der Spek PJ and Lachman HM
Acute onset of severe psychiatric symptoms or regression may occur in children with premorbid neurodevelopmental disorders, although typically developing children can also be affected. Infections or other stressors are likely triggers. The underlying causes are unclear, but a current hypothesis suggests the convergence of genes that influence neuronal and immunological function. We previously identified 11 genes in pediatric acute-onset neuropsychiatric syndrome (PANS), in which two classes of genes related to either synaptic function or the immune system were found. Among the latter, three affect the DNA damage response (DDR): PPM1D, CHK2, and RAG1. We now report an additional 17 cases with mutations in PPM1D and other DDR genes in patients with acute onset of psychiatric symptoms and/or regression that their clinicians classified as PANS or another inflammatory brain condition.
Pubertal- and Stress-Dependent Changes in Cellular Activation and Expression of Excitatory Amino Acid Receptor Subunits in the Paraventricular Nucleus of the Hypothalamus in Male and Female Rats
Parkin C, Ortiz J, Cruz S, Bath KG and Romeo RD
Pubertal maturation is marked by significant changes in stress-induced hormonal responses mediated by the hypothalamic-pituitary-adrenal (HPA) axis, with prepubertal male and female rats often exhibiting greater HPA reactivity compared to adult males and females. Though the implications of these changes are unclear, elevated stress responsiveness might contribute to the stress-related vulnerabilities often associated with puberty.
The Relationship between Early Exposure to General Anesthesia and Neurobehavioral Deficits
Xu J, Wang F, Gao Y, Qi C, Chen T and Yan J
In contemporary medical practice, general anesthesia plays an essential role in pediatric surgical procedures. While modern anesthetic protocols have demonstrated safety and efficacy across various pathological conditions, concerns persist regarding the potential neurotoxic effects associated with early exposure to general anesthesia.
Dexmedetomidine Alleviates the Long-Term Neurodevelopmental Toxicity Induced by Sevoflurane in the Developing Brain
Yang TT, Wei R, Jin FF, Yu W, Zhang F, Peng Y, Zhang SJ, Qi SH and Liu JR
Sevoflurane is an extensively used anesthetic for pediatric patients; however, numerous studies showed that sevoflurane (SEVO) may cause long-term neurodevelopmental toxicity. Dexmedetomidine (DEX) has been shown to be protective against SEVO-induced neurotoxicity, but the mechanism remains unclear. The effects and mechanisms of different DEX administration routes on SEVO-induced neurotoxicity and long-term cognitive defects were determined and further investigated the role of sex in these processes.
Ex vivo magnetic resonance imaging of the human fetal brain
Chen R, Tian C, Zhu K, Ren G, Bao A, Shen Y, Li X, Zhang Y, Qiu W, Ma C, Zhang J and Wu D
The fetal brain undergoes a dynamic process of development during gestation, marked by well-orchestrated events such as neuronal proliferation, migration, axonal outgrowth, and dendritic arborization, mainly elucidated through histological studies. Ex vivo magnetic resonance imaging (MRI) has emerged as a useful tool for 3D visualization of the developing fetal brain, serving as a complementary tool to traditional histology.
The association between ventricle ratio in preterm infants and motor developmental delay
Shin HI, Lee NM, Kim SM, Hwang H, Choi G, Han DH and Kim DK
Introduction Early prediction and timely intervention are particularly essential for high-risk preterm infants. Brain magnetic resonance imaging (BMRI) is frequently used alongside functional evaluations to improve predictions of developmental outcomes. This study aimed to assess voxel-based brain volumetry in extremely preterm infants using BMRI at term equivalent age (TEA) and investigate its association with developmental outcomes. Methods From March 2016 to December 2019, high-risk preterm infants (birth weight < 1500g or gestational age < 32 weeks) with BMRI at TEA and follow-up developmental data assessed by Bayley-III were included. For BMRI volumetry, manual tracing and segmentation were performed on T1-weighted scans, and after smoothing, voxels were calculated for each brain segment. Forty-seven subjects were enrolled and categorized into typical/delayed motor groups Results Results revealed a significant difference in ventricle size and ventricle ratio in BMRI at TEA between the groups. Even after controlling for other factors that could influence developmental outcomes, ventricle ratio emerged as a robust, single predictor for future motor development. Conclusion This study suggests the potential clinical utility of BMRI volumetry in predicting motor development outcomes.
Synaptic Pruning by Microglia: Lessons from Genetic Studies in Mice
de Deus JL, Faborode OS and Nandi S
Neural circuits are subjected to refinement throughout life. The dynamic addition and elimination (pruning) of synapses are necessary for maturation of neural circuits and synaptic plasticity. Due to their phagocytic nature, microglia have been considered as the primary mediators of synaptic pruning. Synaptic pruning can strengthen an active synapse by removing excess weaker synapses during development. Inappropriate synaptic pruning can often influence a disease outcome or an injury response.
Dendritic Morphology of Developing Hippocampal Neurons in Cyp11a1 Null Mice
Jiang HH, Wu TH, Lee LJ, Lee JC, Chung BC, Yang FM and Hu MC
Neurosteroids have a variety of neurological functions, such as neurite growth, neuroprotection, myelination, and neurogenesis. P450scc, encoded by CYP11A1 gene, is the cholesterol side chain cleavage enzyme that catalyzes the first and rate-limiting step in steroidogenesis. In this study, we examine the dendritic morphology in developing hippocampal neurons of Cyp11a1 null mice at P15, a critical period for synapse formation and maturation.
Protective Effects of Early Neonatal Methylxanthine Treatment on Cognitive and Language Outcomes in Premature Infants with and without High-Risk Perinatal Factors
McLeod RM, Rosenkrantz TS and Fitch RH
Caffeine and theophylline are methylxanthines and nonselective adenosine antagonists commonly used to treat apnea of prematurity. Both human and animal data suggest that xanthines also have clinically important long-term neuroprotective effects in the presence of inflammation in the perinatal period as seen following hypoxic-ischemic brain insults. Moreover, these protective effects appear to be more robust when administered shortly (<48 h) after preterm birth.
Peripuberty Is a Sensitive Period for Prefrontal Parvalbumin Interneuron Activity to Impact Adult Cognitive Flexibility
Sahyoun GM, Do TD, Anqueira-Gonzàlez A, Hornblass A and Canetta SE
Developmental windows in which experiences can elicit long-lasting effects on brain circuitry and behavior are called "sensitive periods" and reflect a state of heightened plasticity. The classic example of a sensitive period comes from studies of sensory systems, like the visual system, where early visual experience is required for normal wiring of primary visual cortex and proper visual functioning. At a mechanistic level, loss of incoming visual input results in a decrease in activity in thalamocortical neurons representing the affected eye, resulting in an activity-dependent reduction in the representation of those inputs in the visual cortex and loss of visual perception in that eye. While associative cortical regions like the medial prefrontal cortex (mPFC) do not receive direct sensory input, recent findings demonstrate that changes in activity levels experienced by this region during defined windows in early development may also result in long-lasting changes in prefrontal cortical circuitry, network function, and behavior. For example, we recently demonstrated that decreasing the activity of mPFC parvalbumin-expressing (PV) interneurons during a period of time encompassing peripuberty (postnatal day P14) to adolescence (P50) led to a long-lasting decrease in their functional inhibition of pyramidal cells, as well as impairments in cognitive flexibility. While the effects of manipulating mPFC PV interneuron activity were selective to development, and not adulthood, the exact timing of the sensitive period for this manipulation remains unknown.
Beta Spectral Power during Passive Listening in Preschool Children with Specific Language Impairment
Fatić S, Stanojević N, Jeličić L, Bilibajkić R, Marisavljević M, Maksimović S, Gavrilović A and Subotić M
Children with specific language impairment (SLI) have difficulties in different speech and language domains. Electrophysiological studies have documented that auditory processing in children with SLI is atypical and probably caused by delayed and abnormal auditory maturation. During the resting state, or different auditory tasks, children with SLI show low or high beta spectral power, which could be a clinical correlate for investigating brain rhythms.
Preclinical Milestones in MECP2 Gene Transfer for Treating Rett Syndrome
Jagadeeswaran I, Oh J and Sinnett SE
Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the transcriptional regulator methyl-CpG-binding protein 2 (MeCP2). After gene transfer in mice, exogenous MeCP2 expression must be regulated to avoid dose-dependent toxicity.
Long-Term Neurologic Consequences following Fetal Growth Restriction: The Impact on Brain Reserve
Shah DK, Pereira S and Lodygensky GA
Fetal growth restriction (FGR) corresponds to the fetus's inability to achieve an adequate weight gain based on genetic potential and gestational age. It is an important cause of morbidity and mortality.
Distinguishing Laterality in Brain Injury in Rabbit Fetal Magnetic Resonance Imaging Using Novel Volume Rendering Techniques
Ambwani G, Shi Z, Luo K, Jeong JW and Tan S
Our laboratory has been exploring the MRI detection of fetal brain injury, which previously provided a prognostic biomarker for newborn hypertonia in an animal model of cerebral palsy (CP). The biomarker relies on distinct patterns of diffusion-weighted imaging-defined apparent diffusion coefficient (ADC) in fetal brains during uterine hypoxia-ischemia (H-I). Despite the challenges posed by small brains and tissue acquisition, our objective was to differentiate between left and right brain ADC changes.
Structural and Functional Effects of C5aR1 Antagonism in a Rat Model of Neonatal Hypoxic-Ischemic Encephalopathy
Saadat A, Pallera H, Lattanzio F, Owens D, Gaines A, Ravi SS and Shah T
The complement response activates upon reperfusion in neonatal hypoxic-ischemic encephalopathy (HIE) and contributes to excessive neuroinflammation and worse outcomes. C5a is a powerful anaphylatoxin central to each of the complement pathways, and its engagement with C5aR1 is directly tied to brain injury and neuronal death. Reasoning C5aR1 antagonism can decrease excessive neuroinflammation and thereby improve neurological and functional outcomes, we tested this hypothesis in a rat model of HIE with PMX205, a small molecule that inhibits C5a-C5aR1 interaction.
TFEB overexpression through GFAP promoter disrupts neuronal lamination by dysregulating neurogenesis during embryonic development
Wang L, Cao J, Chen H, Ma Y, Zhang Y, Su X, Jing Y and Wang Y
Transcription factor EB (TFEB), a key regulator of autophagy and lysosomal biogenesis, has diverse roles in various physiological processes. Enhancing lysosomal function by TFEB activation has recently been implicated in restoring neural stem cells (NSCs) function. Overexpression of TFEB can inhibit the cell cycle of newborn cortical NSCs. It has also been found that TFEB regulates the pluripotency transcriptional network in mouse embryonic stem cells independent of autophagy lysosomal biogenesis. This study aims to explore the effects of TFEB activation on neurogenesis in vivo through transgenic mice.
Left OFC Activation in Functional Near-Infrared Spectroscopy during an Inhibitory Control Task in an Early Years Sample: Integrating Stress Responses with Cognitive Function and Brain Activation
Ramacciotti MCC, Soares Junior RDS, Sato JR and Gualtieri M
Previous functional near-infrared spectroscopy (fNIRS) studies using Go/No-Go (GNG) tasks have focused on brain activation in relation to cognitive processes, particularly inhibitory control (IC). The results of these studies commonly describe right hemispheric engagement of the dorsolateral, ventromedial, or inferior frontal regions of the prefrontal cortex. Considering that typical healthy cognitive development is negatively correlated with higher cortisol levels (which may alter brain development), the overarching aim of the current study was to investigate how elevated stress (due to unforeseeable events such as the pandemic) impacts early cognitive development.
Region-Specific Brain Volume Changes Emerge in Adolescence in the Valproic Acid Model of Autism and Parallel Human Findings
King C, Mali I, Strating H, Fangman E, Neyhard J, Payne M, Bossmann SH and Plakke B
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social and communication deficits, cognitive dysfunction, and stereotyped repetitive behaviors. Regional volume changes are commonly observed in individuals with ASD. To examine volumetric dysregulation across adolescence, the valproic acid (VPA) model was used to induce ASD-like phenotypes in rats.
The Intersection of Epigenetic Alterations and Developmental State in Pediatric Ependymomas
Kardian AS and Mack S
Ependymomas are the third most common brain cancer in children and have no targeted therapies. They are divided into at least 9 major subtypes based on molecular characteristics and major drivers and have few genetic mutations compared to the adult form of this disease, leading to investigation of other mechanisms.
Development of A New Scoring System in Higher Animals for Testing Cognitive Function in the Newborn Period: Effect of Prenatal Hypoxia-Ischemia
Shi Z, Sharif N, Luo K and Tan S
Introduction Enhanced models for assessing cognitive function in the neonatal period are imperative in higher animals. Postnatal motor deficits, characteristic of cerebral palsy, emerge in newborn kits within our prenatal-rabbit model of hypoxia-ischemia (HI). In humans, prenatal HI leads to intellectual disability and cerebral palsy. In a study examining cognitive function in newborn rabbits, we explored several questions. Is there a distinction between conditioned and unconditioned kits? Can the kits discern the human face or the lab coat? Do motorically-normal kits, born after prenatal HI, exhibit cognitive deficits? Methods The conditioning protocol was randomly assigned to kits from each litter. For conditioning, the same human, wearing a lab coat, fed the rabbit kits for 9 days before the cognitive test. The 6-arm radial maze was chosen for its simplicity and ease of use. Normally appearing kits, born after uterine ischemia at 79% or 92% term in New Zealand White rabbits, were compared to Naïve kits. On postpartum day 22/23 or 29/30, the 6-arm maze helped determine if the kits recognized the original feeder from bystander (Test-1) or the lab coat on bystander (Test-2). The use of masks of feeder/bystander (Test-3) assessed confounding cues. A weighted score was devised to address variability in entry to maze arms, time, and repeated-trial learning. Results In conditioned kits, both Naïve and HI kits exhibited a significant preference for the face of the feeder, but not the lab coat. Cognitive deficits were minimal in normal-appearing HI kits. Conclusion The weighted score system was amenable to statistical manipulation.
Timing of methamphetamine exposure during adolescence differentially influences parvalbumin and perineuronal net immunoreactivity in the medial prefrontal cortex of female, but not male, rats
Brinks AS, Carrica LK, Tagler DJ, Gulley JM and Juraska JM
Adolescence involves significant reorganization within the medial prefrontal cortex (mPFC), including modifications to inhibitory neurotransmission that may be mediated through parvalbumin (PV) interneurons and their surrounding perineuronal nets (PNNs). These developmental changes, which can result in increased PV neuron activity in adulthood, may be disrupted by drug use resulting in lasting changes in mPFC function and behavior. Methamphetamine (METH), which is a readily available drug used by some adolescents, increases PV neuron activity and could influence the activity-dependent maturational process of these neurons.