Molecular Brain

BackgroundRNA editing is a post-transcriptional modification that alters the sequence of an RNA transcript. Two types of RNA editing were found in mammals, involving the enzymatic deamination of either adenosine to inosine (A-to-I) or cytidine to uridine (C-to-U) nucleotides in RNA. A-to-I, which is the most common form of RNA editing, is mediated by the ADAR (adenosine deaminases acting on RNA) family of enzymes, ADAR1, ADAR2, and ADAR3. The editing event alters the hydrogen bond pairing of nucleobases, and the editing site will be recorded as guanosine rather than the original adenosine. Indeed, RNA editing deregulation has been linked to several nervous and neurodegenerative diseases. In this project work is done on Alzheimers disease (AD) and the samples are from anterior cingulate cortex of human brain tissue. AD is the main dementia in the world and a neurodegenerative condition prevalent in the elderly. MethodologyA total of 20 raw RNA-sequencing data samples containing 10 controls and 10 Alzheimers disease (AD) cases were collected from NCBI using SRA Toolkit. Quality assessment was performed using FastQC and processed using Trimmomatic. Alignment was done using STAR RNA-seq aligner. RNA editing detection was performed using REDItools, detected sites were subsequently annotated against the REDIportal database. The resulting control-specific and disease-specific novel editing sites were merged into a single dataset containing exclusively novel, group-specific A-to-I editing events. This merged dataset was subsequently used for downstream feature extraction and machine learning analysis. Probability-based filtering was done to extract high-confidence disease associated sites and their gene list was used for computational level biological validation, pathway and functional enrichment analysis as well as overlap with known AD loci. ResultsRandom Forest showed the highest accuracy score (0.804) and ROC-AUC score (0.854). Most important features that differentiated control and diseased novel sites in random forest were coverage ([~]0.35), editing level ([~]0.33) and GC content ([~]0.15). The AEI mean values is higher in both male and female diseased cases ([~]0.48-0.50) but less in male and female control cases ([~]0.14-0.21). The mean values of ADAR1_CPM higher in control cases (123.65-143.30) and is less in diseased cases (88.35-97.93), ADAR2_CPM is almost equal in all cases ([~]3.7-4.7) and ADAR3_CPM is very less in all the cases ([~]0-0.02). Most candidate editing site were present in exon ([~]62-67 %) CDS regions ([~]17-21%) and relatively smaller fraction of gene ([~]15-16 %). Editing alterations preferentially affect molecular systems governing synaptic structure, neurotransmission, and central nervous system integrity. In the main set -of the 2576 high-confidence genes identified, 33 overlapped with AD GWAS loci. In the core set -of the 1367 high-confidence genes identified, 11 overlapped with AD GWAS loci. ConclusionFeature like coverage, editing level and GC content contributed most. Alu sites are negligible as compared to non-alu sites but the AEI mean values are higher in diseased cases than in control cases. The mean values of ADAR1_CPM are higher than ADAR2_CPM and ADAR3_CPM.Sex does not play a major factor. High-confidence disease-associated RNA editing sites are strongly biased toward transcript-centric regions, particularly exons, with a notable subset affecting coding sequences. Importantly, enrichment of neurodegeneration-associated pathways and cognition-related human phenotypes further supports the disease relevance of these gene networks. RNA editing events in Alzheimers cortex may represent a regulatory mechanism largely independent of inherited genetic susceptibility loci.

Mutations in several genes are known to cause familial forms of Parkinsons disease (PD), including mutations in the vacuolar protein sorting 35 ortholog (VPS35) gene linked to late-onset, autosomal dominant PD. VPS35 encodes a core subunit of the retromer complex which functions in endosomal sorting and recycling. It remains unclear how the pathogenic D620N mutation in VPS35 disrupts retromer function to induce neurodegeneration in PD. Using cell-and rodent-based models expressing D620N VPS35, we performed interactome proteomics to identify alterations underlying the pathogenic effects of D620N VPS35 in PD. Using overexpression of VPS35 variants in HEK-293T cells, we conducted tandem affinity purification (TAP) or co-immunoprecipitation (co-IP) with protein chemical crosslinking to determine the native and non-native protein interactomes of wild-type (WT) and D620N VPS35, respectively. Notably, we can confirm the reduced interaction of D620N VPS35 with components of the WASH complex. Additionally, using a viral-mediated gene transfer model of human D620N VPS35 overexpression in adult rat brain, we identify the first brain-specific protein interactome of VPS35. These overexpression models reveal remarkably similar interaction profiles of WT and D620N VPS35, suggesting that the D620N mutation has a subtle effect on the overall VPS35 protein interactome. We also conducted proteomic analysis of brain tissue from a D620N VPS35 knockin (KI) mouse model that expresses VPS35 at endogenous levels. Using co-IP from hemi-brain or striatal extracts of WT and D620N VPS35 KI mice, we reveal a high degree of similarity between the brain interactomes of WT and D620N VPS35, further suggesting a subtle effect of the D620N mutation on VPS35 protein interactions. Notably, in both hemi-brain and striatum, we find a selective decrease in the interaction of two known interactors, TBC1D5 and VPS29, with D620N VPS35. We also performed global proteomic analysis of striatal tissue from D620N VPS35 KI mice and reveal a high degree of similarity between WT and D620N, further suggesting a subtle effect of this mutation. Together, our study provides a comprehensive evaluation of the VPS35 protein interactome and reveals a selective effect of the PD-linked D620N mutation in mammalian cells and brain. Our study provides key insight into the mechanisms of retromer dysfunction in VPS35-linked PD.

Ischemic stroke triggers a cascade of molecular and cellular processes leading to fibrotic scar formation, entailing activation of brain platelet-derived growth factor receptor (PDGFR){beta}+ cells. Kruppel-like factor (KLF)4 plays an important role in regulating the activation of peripheral PDGFR{beta}+ perivascular cells in response to hypoxia/ischemia. Herein, we aimed to characterize the spatiotemporal responses of brain PDGFR{beta}+ cells while assessing the contribution of KLF4. This was achieved using transgenic mice that enable tracking or conditionally depleting KLF4 in PDGFR{beta}+ cells, which were subjected to experimental ischemic stroke. Next, we employed point pattern analysis (PPA) and topological data analysis (TDA) to quantitatively characterize cell phenotypic changes and spatial distribution over injury progression after ischemic stroke. We show that brain PDGFR{beta}+ cells rapidly become reactive and early localize to regions prone to irreversible damage. We report the emergence of parenchymal PDGFR{beta}+ cells, which cannot be causally linked to proliferation or vascular detachment. Moreover, our analysis reveals that KLF4 is barely expressed in brain PDGFR{beta}+ cells under normal conditions, and that its expression is slightly induced in reactive cells in the injured brain. Notably, specific attenuation of KLF4 induced expression in PDGFR{beta}+ cells does not affect cell reactivity and spatiotemporal distribution, nor scar formation and injury severity. These observations suggest that in contrast with the periphery, KLF4 is not implicated in regulating the responses of brain PDGFR{beta}+ cells. Our results indicate that the reactivity of brain PDGFR{beta}+ cells after stroke is spatiotemporally diverse, evolve over injury progression, and is distinct from peripheral perivascular cells. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=65 SRC="FIGDIR/small/712632v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1149c62org.highwire.dtl.DTLVardef@26edaaorg.highwire.dtl.DTLVardef@1bd3d35org.highwire.dtl.DTLVardef@fd8030_HPS_FORMAT_FIGEXP M_FIG C_FIG

PurposeThe optic nerve head (ONH) is a central feature of the retina, affected in many human ocular pathologies, yet it has remained underexplored in most mouse models of disease. We hypothesize that the analysis of the ONH can yield valuable insight into the phenotype of retinal diseases and that pathological changes can be detected using state-of-the-art optical coherence tomography (OCT). MethodsFour mouse models - the 5xFAD, PS19 and APP/PS1 models of Alzheimers disease (AD) as well as the SOD1 knockout mouse model - were imaged using a polarization-sensitive OCT system to investigate potential disease related changes of the ONH. 5xFAD and SOD1 animals were investigated longitudinally to study disease progression. Additionally, aging effects in wild type mice were studied. ResultsTwo different analysis methods for the segmentation of the ONH were implemented and evaluated. Longitudinal changes to the ONH in 5xFAD animals were observed, specifically an increase of ONH volume from 3 to 5 months of age followed by a strong decrease until 9 months of age. Significant differences between transgenic (tg) and non-transgenic (ntg) animals, as well as sex dependent distinctions were found. Also, for the APP/PS1 model disease related differences between ntg and tg APP/PS1 were significant. ConclusionsWe demonstrated a simple segmentation of the ONH structure based on OCT intensity images and show its potential as a preclinical biomarker in amyloid mouse models of AD.

BackgroundParkinsons disease (PD) is a prevalent neurodegenerative disorder characterized by progressive motor dysfunction and broad cellular impairment, including significant disruptions in lysosomal function, lipid metabolism, and intracellular trafficking. Glycosphingolipids (GSLs), critical for various cellular processes, depend on effective lysosomal degradation. Aberrant GSL metabolism has been linked to PD pathology, and glycoprotein non-metastatic melanoma protein B (GPNMB) has emerged as a biomarker associated with lysosomal dysfunction and lipid imbalance in PD. ObjectivesTo assess the relationship between GPNMB and GSL levels in cerebrospinal fluid (CSF) and plasma from PD patients and controls within the BioFIND cohort. We also investigated potential sex differences and associations with PD-related biomarkers such as -synuclein. MethodsGSL species and GPNMB protein levels were quantified using high-performance liquid chromatography (HPLC) and ELISA assays, respectively, in matched CSF and plasma samples from PD patients and controls. ResultsLevels of the paraglobosides GSL species, alpha-2,3SpG and pGb were significantly elevated in the plasma of PD patients compared to healthy controls, while levels of the ganglioside GD1a and the lacto-series GSL, Leb combined (GD1a + Leb), were significantly reduced in PD. GPNMB levels positively correlated with several GSL species in both plasma and CSF. Plasma GSLs and GPNMB concentrations were significantly higher in females compared to males, independent of PD diagnosis. CSF GPNMB correlated positively with age and -synuclein concentrations. InterpretationOur findings confirm that GSL metabolism is altered in PD. They also highlight significant sex-based biochemical variations in GSL and GPNMB levels, emphasizing the need for sex-specific analyses in PD biomarker research. The relationship between GSLs and GPNMB supports their potential as interconnected biomarkers of lipid pathology in PD.

BackgroundIndividual clinical cognitive assessments (CCA) for Alzheimers disease (AD) provide broad disease stratification but are limited in sensitivity and specificity, requiring integration of multiple CCA for optimal disease staging. Recent work from our lab suggests that neuro-metabolic and vascular dysregulation (MVD) occurs early in AD, prior to clinical symptoms, and may provide higher sensitivity and specificity than CCA alone. In this study, we combined three widely accepted CCA with MVD readouts and developed a multimodal ensemble machine learning approach across the AD spectrum to predict disease stage and grade. MethodsAD subjects (N=372) across the disease spectrum with imaging (PET:18F-FDG, MRI:T1w, T2 FLAIR, ASL) and CCAs (ADAS-Cog, CDR, MoCA) data were analyzed from ADNI. Imaging data were registered to MNI152+, z-scored relative to cognitively normal controls, and processed for MVD. A clinical-set-enrichment analysis (CSEA) was developed to link regional brain changes with CCA scores, map changes to functional categories, project them into a 3D Cartesian space, and model trajectories, thus revealing at-risk and resilient regions. In addition, an ensemble machine-learning approach was utilized for disease stage classification, and a disease grading scheme across the AD spectrum was developed to further stratify within disease stages. FindingsRegional data followed an MVD pattern across AD stages stratified by CSEA scores. Females showed greater stage separation along the CCA axis within each region, indicating faster disease progression. Moreover, progression in at-risk brain regions (e.g., mid- and inf-temporal gyri, amygdala) was associated with longer disease path lengths, whereas progression in resilient brain regions (supramarginal gyrus) was not. Moreover, our classification and grading approach can predict AD stage and grade independent of amyloid-beta and tau with high precision and accuracy. InterpretationA framework was developed to evaluate MVD and CCA variations across the AD spectrum, thereby distinguishing at-risk and resilient brain regions. Distinct disease trajectories were identified, and a new data-driven grading scheme was proposed to highlight the potential for precision medicine and therapeutic evaluation. FundingNIH T32AG071444

Food anticipatory activity (FAA) is a robust behavioral output of food-entrained circadian rhythms, characterized by increased locomotor activity prior to scheduled feeding. Despite the social nature of rodents, FAA is almost exclusively studied in singly housed animals, leaving the influence of social context largely unexplored. Here, we used implanted wireless devices to measure individual locomotor activity and subcutaneous body temperature in group-housed mice and compared these measures to singly housed controls. Social housing significantly suppressed FAA in both male and female mice. In parallel, preprandial increases in body temperature were markedly attenuated in group-housed animals. These findings demonstrate that FAA is a flexible, state-dependent behavior that reflects both circadian timing and energetic demand. Together, these results identify social context as an important and underappreciated determinant of food-entrained circadian biology. HighlightsO_LISocial housing suppresses food anticipatory activity in both male and female mice. C_LIO_LIAnticipatory temperature rises are dampened in social settings. C_LIO_LISocial housing provides a thermal buffer, reducing pre-meal metabolic demand. C_LIO_LIMales exhibit a more pronounced suppression of FAA than females in group environments. C_LIO_LIFAA is a flexible, state-dependent behavior modulated by the social environment. C_LI

{gamma}-secretase is a multi-subunit enzyme complex responsible for cleaving hundreds of substrates in diverse cellular contexts. Variation in subunit composition - including the use of alternate catalytic subunits Presenilin 1 (PSEN1) and Presenilin 2 (PSEN2) - results in diverse {gamma}-secretase complexes. Point mutations in PSEN1 and PSEN2 cause familial forms of Alzheimers disease, while loss-of-function mutations in the {gamma}-secretase subunits PSEN1, PSENEN and NCSTN cause acne inversa. To advance therapeutic strategies targeting {gamma}-secretase in Alzheimers disease, a better understanding of individual {gamma}-secretase complexes is required. In this study, we used CRISPR-Cas9 genome engineering to generate PSEN2-knockout iPSCs in order to compare the consequence of PSEN2 knockout versus PSEN1 knockout in iPSC-derived brain cells. In contrast to PSEN1-knockout, PSEN2-knockout did not alter APP cleavage or A{beta} generation in iPSC-neurons, nor did it disrupt Nicastrin maturation. Similarly, PSEN2-knockout had little impact on TREM2 processing in iPSC-microglia. Instead, our data indicate that loss of PSEN2 primarily impacts the endo-lysosomal system in iPSC-neurons, causing an accumulation of early endosome markers and a reduction in lysosomal markers - phenotypes not observed in PSEN1-knockout neurons. Taken together, these findings highlight distinct and non-redundant functions of PSEN1 and PSEN2 in human brain cells, reinforcing findings in animal models and subcellular localisation studies. This work advances our understanding of distinct {gamma}-secretase complex functions and provides insights that will support future therapeutic efforts to inhibit, modulate or stabilise {gamma}-secretase.

Huntingtons disease (HD) is a progressive neurodegenerative disease caused by a mutation in the exon 1 of the huntingtin (HTT) gene, which leads to an extended polyglutamine (polyQ) tract in the mutant protein. As a result, mutant huntingtin (mHTT) exon 1 fragments aggregate in cells, which disrupts proper neuronal function and eventually induces cell death. The selective reduction of these toxic mHTT fragments without disturbing the wild-type full-length HTT function would be a potential therapeutic strategy to treat and prevent HD. Intracellular antibodies (intrabodies) have emerged as an attractive strategy to specifically target disease-related proteins, with VHH intrabodies being of high interest as they are much smaller than single-chain variable fragments (scFv). Here, we describe the identification and development of VHH 1 as a lead candidate intrabody targeting the first 17 amino acids of the mHTT protein, using a humanized VHH page-display library to screen against mHTT(Q46) exon 1 to identify potential binders. Next, we further optimized VHH 1 into VHH 1a to improve cytoplasmic solubility. Using immortalized mouse striatal cells that express inducible untagged mHTT exon 1 fragments, we investigated the effects of the intrabody on soluble and insoluble mHTT species via microscopy and biochemical assays. We showed that the VHH 1a intrabody reduces the levels of insoluble mHTT species, thereby effectively interrupting the aggregation process. This study highlights the potential for VHH intrabodies to specifically target mHTT fragments, enabling therapeutic strategies to delay and prevent HD pathology. HighlightsO_LIThree binders were down-selected from a phage-display library to bind HTT N17 C_LIO_LIVHH 1a intrabody is the most efficient at reducing mutant HTT exon 1 aggregation C_LIO_LIVHH 1a acts on soluble HTT exon 1 oligomers to block the transition to inclusion body C_LI

The design of the classical fluorescence microscope has undergone few changes since the 1970s-1980s, when Ploemopak modules with filter cubes became widespread. Most of these changes have been in the replacement of mercury and xenon lamps with LED illuminators in the 2010s. However, this does not mean that this stable design cannot be improved upon. New method: The implementation of a vibrating optical fiber, positioned using a micromanipulator and connected to any suitable type of laser, enables a full spectrum of fluorescence research. This work presents an advanced version of the Ellis concept, in which light is delivered directly onto the sample, rather than into the filter cube (technical novelty).To confirm the functionality of the microscope, vibrational slices of mouse brain stained with three fluorescent markers (B3-PPC, DiI and DiD) covering most of the visible spectrum were examined. The fiber-optic illumination system eliminates the need for bulky and obsolete high-voltage plasma arc lamp units without compromising image quality (confirmed by the USAF 1951 test and SDNR assessment on fluorescent beads). Furthermore, the optical fiber mounted on manipulators is convenient and easy to integrate, for example, into stereomicroscopes for scanning large brain tissue samples.

Emerging preclinical and clinical evidence suggests that low frequency hemodynamic oscillations drive CSF flow, which in turn mediates glymphatic clearance. The current study investigated whether CO2-induced low frequency hemodynamic oscillations during magnetic resonance imaging would increase clearance of proteins (glial fibrillary acidic protein, neurofilament light chain, ptau217 and brain-derived tau) from brain to blood, and temporarily improve cognitive performance in individuals with chronic traumatic brain injury (TBI) and age/sex-matched healthy controls. Results indicated that cerebrovascular reactivity, normalized CSF volume, and predicted brain age significantly differed between chronic TBI and controls, while bulk CSF flow differed only at trend levels. Multiple protein concentrations were significantly increased at [~]45 minutes post-hypercapnia, decreased at [~]90 minutes, and returned to pre-hypercapnia levels by [~]150 minutes. Protein efflux was more strongly associated with total CSF volume and total white matter volume rather than cerebrovascular reactivity or bulk CSF flow. Both groups exhibited reduced cognitive interference post-hypercapnia, and hypercapnia associated symptoms quickly returned to baseline levels. In conclusion, hypercapnia temporarily increases clearance of multiple neural abundant proteins into blood, and this effect is moderated by atrophy. Current results suggest that hypercapnia may therapeutically combat pathological protein aggregation post-trauma, and prophylactically during normal aging.

In previous studies by the author on binocular vision with the asymmetric eye (AE), which models a healthy human eye with misaligned optical components, the results were primarily presented in the Rodrigues vector (RV) framework and supported by simulations and 3D visualizations in GeoGebras dynamic geometry environment. In this paper, the novel geometric kinematics of the human eye, i.e., the eye with misaligned optics, and simplified assumptions about eye rotations (the eyes translational movements are disregarded) are developed within the framework of rigid-body rotations. Despite the eyes misaligned optical components (all eyes axes differ), the geometric formulation, which can only be approximated, yields excellent accuracy as demonstrated by simulations. The originality of the analysis lies in a precise geometric decomposition of the eyes posture changes into torsion-free (geodesic) and torsional (non-geodesic) rotations. This decomposition is extended to the corresponding decomposition of the angular velocity. A novel derivation of the eyes angular velocity from the RV formulation of the eye kinematics is proposed.

BackgroundPerinatal mood and anxiety disorders (PMADs) are among the most common and consequential complications of pregnancy. The perinatal period is also characterized by profound hormonal fluctuations and large-scale brain plasticity. However, the mechanisms linking these neurobiological changes to psychiatric risk are poorly understood. Prospective, clinically informed studies are needed to identify quantitative biomarkers and clarify pathways linking perinatal neurobiology to PMADs risk. MethodsThis report describes the design of a prospective, longitudinal cohort study integrating multimodal neuroimaging, biofluid sampling, and deep clinical phenotyping to enable precision characterization of neurobiological trajectories of PMADs risk. Twenty-five individuals at elevated risk for PMADs will be recruited prior to conception and followed across six in-person timepoints spanning the menstrual cycle, pregnancy, and early postpartum, with additional remote follow-ups through the first postpartum year. Data collection includes high-resolution structural MRI, functional brain mapping using multi-echo resting-state fMRI, diffusion MRI, arterial spin labeling, ultra-high field MR-based techniques for measuring glutamate (GluCEST and 1HMRS), biofluid sampling, and comprehensive clinical, behavioral, and cognitive assessments. Structured clinical interviews assess categorical diagnoses while dimensional symptom measures capture heterogeneity and transdiagnostic features of perinatal psychopathology. Longitudinal analyses will model nonlinear trajectories of brain and symptom change across the perinatal period as well as evaluate whether preconception network features and menstrual cycle-related brain changes are associated with subsequent perinatal symptom emergence. DiscussionThis cohort study establishes a longitudinal, multimodal framework for investigating neurobiological changes across the transition to pregnancy in individuals at elevated risk for PMADs. By anchoring pregnancy-related brain changes to preconception and menstrual cycle-related variability within the same individuals, this study is designed to evaluate associations between preconception hormone sensitivity, pregnancy-induced neuroplasticity, and PMADs risk. The resulting dataset will provide a deeply phenotyped longitudinal resource for investigating brain-behavior relationships across the perinatal period. Findings are expected to inform future larger-scale studies aimed at advancing mechanistic understanding of PMADs, improving individualized risk stratification, and supporting development of personalized preventive and neuromodulatory interventions.

SHORT ABSTRACTA key barrier to developing effective drugs for disorders of the central nervous system (CNS) is understanding their impact on neural circuits. This protocol demonstrates how physics-based neural simulations can be used to interpret electrophysiological biomarkers of neurotherapeutics, providing a mechanistically grounded approach to the development of neurotherapeutics. LONG ABSTRACTElectroencephalography (EEG) and electrophysiology methods provide millisecond resolution biomarkers for central nervous system disorders and are used to assess treatment-related effects. However, lack of understanding about the neural mechanisms generating such biomarkers impedes the development of diagnostics and therapeutics based on these signals. The Human Neocortical Neurosolver (HNN) is an open-source biophysical modeling software that connects localized EEG biomarkers to their multi-scale neural generators. This protocol demonstrates a hypothesis-driven workflow using HNN to test possible neural mechanisms of neurotherapy-induced EEG biomarkers by optimizing parameters to achieve a fit between simulated and empirical current source waveforms. Corresponding multi-scale cell- and circuit-level activity can then be visualized and quantified, providing validation targets for model predictions in follow up empirical studies. An example is provided which shows how to examine the generating mechanisms of the early event-related potential (ERP) components of an auditory evoked response (P1, N1 and P2) and to assess changes following neural circuit modification due to neurotherapeutic administration. This protocol demonstration enables scientists to design simulation experiments to develop testable predictions on how EEG biomarkers reflect neural circuit mechanisms of example therapeutics. A similar protocol can be applied to study disease mechanisms or other therapies.

The gliovascular unit (GVU), a specialized interface between the brain and the vascular system, assembles and matures after birth and establishes essential homeostatic functions, including blood-brain barrier integrity, metabolic exchanges, fluid drainage, neurovascular coupling, and immune surveillance. Here, we systematically compared the postnatal maturation of the cortical GVU in male vs. female mice. On P15, males exhibited a transiently greater vessel density and a higher level of aquaporin 4 expression in perivascular astrocyte processes. Females exhibited a higher density of perivascular macrophages expressing the lymphatic vessel endothelial hyaluronan receptor 1 (Lyve-1), along with earlier development of arterial vascular smooth muscle cells and greater cerebral blood flow. Transcriptomic profiling during the P5-P120 period revealed sex-specific developmental trajectories within the GVU, with the most prominent differences on P5. Taken as a whole, our results highlight pronounced sex-dependent differences in GVU assembly, GVU maturation, and the development of molecular programs that might influence brain physiology and vulnerability to neurodevelopmental disorders.

Therapeutic brain stimulation is believed to target specific networks, but targeting approaches for memory remain debated. For other symptoms, neuromodulation targets have been localized by mapping connectivity of lesions and stimulation sites to specific symptoms. This approach has yielded networks for global memory, but it remains unclear whether it applies to specific types of memory. Here, we mapped connectivity of stimulation sites, lesions, and atrophy patterns associated with different memory types. We included 544 individuals across three datasets: transcranial magnetic stimulation (N=262), penetrating head trauma (N=169), and ischemic stroke (N=113). We identified a network preferentially connected to lesions and stimulation sites specifically associated with changes in visual memory. Of note, the direction of this effect was inverted depending on whether lesions or stimulation occurred at younger age or an older age, consistent with prior results. This age effect was replicated in an independent dataset of patients with preclinical Alzheimers disease (N=1240). To examine neuromodulation targets, we computed electrical field models for potential TMS sites that overlap with the networks derived from each stimulation or lesion dataset; the resulting targets intersected with established targets that demonstrated efficacy for treating memory impairment - precuneus, cortical-hippocampal network, and dorsolateral prefrontal cortex - with peak intersection at medial posterior parietal lobe, angular gyrus, and left anterior middle frontal gyrus, respectively. Future head-to-head clinical trials are needed to systematically compare these proposed neuromodulation targets against each other. One Sentence SummaryNeuromodulation targets for visual memory diverge by age at the time of injury or stimulation.

INTRODUCTIONLocus coeruleus and glymphatic dysfunction are linked both to Alzheimers disease (AD) and, recently, to infraslow oscillation in sleep spindle (sigma) activity (ISO). Here we hypothesise ISO integrity is a critical link between sleep and AD. METHODSWe analyzed non-rapid eye movement sleep EEG from AD and controls, extracting ISO peak amplitude, intrinsic frequency, and bandwidth from the sigma-power time course. We assessed group differences and correlations with plasma biomarkers (A{beta}42/40, pTau181 and 217, NfL, GFAP). RESULTSISO peak amplitude was significantly reduced in AD, while intrinsic frequency and bandwidth were preserved. ISO peak amplitude positively correlated with A{beta}42/40 ratio, and ISO bandwidth correlated with GFAP and NfL levels, and with lower verbal memory retention. DISCUSSIONSuch selective weakening of ISO in AD is consistent with LC dysfunction and impaired glymphatic cycling. ISO may be a novel mechanism and electrophysiological marker linking sleep microarchitecture to AD pathology.

Objectives: Acute gastroenteritis is a leading cause of pediatric emergency department (ED) visits. While ondansetron reduces vomiting, intravenous rehydration, and hospital admissions, its efficacy when initiated at triage remains unclear. We aimed to evaluate whether triage nurse-initiated administration of ondansetron in children with suspected gastroenteritis reduces the proportion of patients requiring observation following initial physician assessment. Methods: We conducted a randomized, double-blind, placebo-controlled trial in a tertiary pediatric ED in Canada. Children aged 6 months to 17 years presenting with morae than 3 episodes of vomiting in the preceding 24 hours (including 1 within 2 hours of arrival), were eligible. At triage, we randomized participants to receive liquid ondansetron or a color- and taste-matched placebo. The primary outcome was the proportion of patients requiring observation after the first physician evaluation. Secondary outcomes included post-intervention vomiting, ED length of stay, patient comfort, and 48-hour return visits. The trial was registered at ClinicalTrials.gov (NCT03052361). Results: Recruitment was stopped prematurely due to the COVID-19 pandemic. Ninety-one participants were randomized to ondansetron (n= 44) or placebo (n= 47). Overall, 40 patients (45%) were discharged immediately after the initial physician assessment, with no difference between the ondansetron and placebo groups (44% vs. 45%; absolute difference -1%, 95% CI: -20% to 19%). No significant differences were observed in all secondary outcomes. Conclusion: In this trial, triage nurse-initiated ondansetron administration did not reduce the need for ED observation in children with presumed gastroenteritis. While being underpowered, this study could inform researchers planning larger clinical trials.

Objective Cerebral palsy (CP) affects approximately 1 million Americans and 18 million individuals worldwide, yet contemporary US epidemiologic data remains limited. We aimed to use Cerebral Palsy Research Network (CPRN) clinical registry to describe demographics and clinical characteristics of individuals with CP across the US and determine associations with gross motor function and genetic etiology. Methods Registry subjects were included if they had clinician-confirmed CP and prospectively entered data for Gross Motor Function Classification System (GMFCS) Level, gestational age, genetic etiology, CP distribution, and tone/movement types. Logistic regression was used to determine which of these variables plus race, sex, ethnicity, and age were associated with GMFCS level and genetic etiology. Results A total of 9,756 children and adults with CP from 22 CPRN sites met inclusion criteria. Participants were predominantly White (73.0%), male (57.3%), non-Hispanic (87.8%), and younger than 18 years (73.7%). Most were classified as GMFCS levels I-III (55.6%), born preterm (52.8%), had spasticity (83.8%), and had quadriplegia (41.9%); 12.2% were identified as having a genetic etiology. Tone/movement types, CP distribution, and gestational age were significantly associated with both GMFCS level and genetic etiology (p<0.001). Compared to White individuals, Black individuals were more likely to have greater gross motor impairment (p<0.001). Conclusion In this large US cohort, clinical and demographic factors, including race, were associated with gross motor function and genetic etiology in CP. These findings highlight persistent disparities and demonstrate the value of a national clinical registry for informing prognostication, quality improvement efforts, and targeted genetic testing strategies.

BackgroundPatent ductus arteriosus (PDA) is a common and potentially serious cardiovascular condition in preterm infants, particularly those with low gestational age and birth weight. Its management remains controversial due to variability in screening, diagnostic criteria, and treatment strategies. This study aimed to evaluate risk factors, outcomes, and management strategies for PDA in preterm infants, and to identify predictors of clinical and echocardiographic response to therapy. MethodsWe conducted a retrospective cohort study over a 4-year period (2016-2019) in the neonatal intensive care unit (NICU) of a tertiary care center. All consecutive preterm infants admitted during the study period were eligible. Infants with echocardiographically confirmed PDA who received pharmacological treatment with intravenous paracetamol or ibuprofen were included in the analysis. Missing data were minimal and handled using available-case analysis. Statistical analyses included descriptive statistics, Pearsons chi-square test, and multivariable logistic regression. ResultsAmong 2154 preterm infants admitted to the NICU, 60 were diagnosed with PDA (incidence : 2.8%). The mean gestational age was 29 {+/-} 2.6 weeks, and the median birth weight was 1200 g. Respiratory distress occurred in 95% of cases, mainly due to hyaline membrane disease (86.7%). PDA was symptomatic in 80% of infants. First-line treatment resulted in clinical improvement in 77% and ductal closure in 83.3% of cases, most within 3 days. Predictors of successful closure included gestational age [&ge;] 28 weeks (OR = 5.9; 95% CI : 1.7-20.2) and antenatal corticosteroid exposure (OR = 1.2; 95% CI : 1.0-1.6). Overall mortality was 35% and was significantly higher in infants < 28 weeks (OR = 5.0; 95% CI : 2.4-10.3). Clinical improvement (OR = 3.7) and echocardiographic closure (OR = 4.5) after first-line treatment were associated with reduced mortality. ConclusionsPDA in preterm infants is associated with substantial morbidity and mortality, particularly in those born before 28 weeks of gestation. Early diagnosis, antenatal corticosteroid exposure, and timely pharmacological treatment may improve outcomes. Systematic echocardiographic screening in high-risk neonates should be considered.