Search Results (98)

Objectives: Autism spectrum disorder (ASD) is increasingly conceptualized as a neurodevelopmental condition with prenatal origins. Advances in fetal magnetic resonance imaging (MRI), including high-resolution structural imaging and resting-state functional connectivity analysis, now enable in vivo characterization of the developing human brain before birth. This review examines whether fetal MRI biomarkers are associated with later ASD diagnosis or autistic traits. Methods: We conducted a PRISMA-informed narrative review of human studies identified through MEDLINE, EMBASE, SCOPUS, and Web of Science. Eligible studies included original human investigations using fetal MRI to assess brain structure and/or function, with postnatal ASD diagnosis or standardized autistic-trait outcomes. Results: Eight eligible studies provide converging evidence that neurodevelopmental divergence associated with ASD may be detectable in utero. Structural analyses consistently report prenatal volumetric alterations, particularly enlargement of the insular cortex between the second and third trimesters. Additional findings of regional overgrowth and hemispheric asymmetries suggest distributed deviations in cortical maturation. Functional fetal MRI studies further demonstrate atypical large-scale network organization prior to birth. Altered connectivity within cingulate, prefrontal, temporal, and cerebellar circuits has been prospectively associated with later autistic traits, indicating that network-level integration may diverge before behavioral symptoms emerge. Evidence from high-risk conditions, including isolated ventriculomegaly and tuberous sclerosis complex, reinforces the association between prenatal structural abnormalities and increased ASD risk. Conclusions: Current evidence suggests that structural and functional brain alterations identifiable by fetal MRI may precede the clinical manifestation of ASD. These findings support a model of ASD as a condition potentially rooted in prenatal neurodevelopmental divergence. However, larger, standardized, multicenter studies are required before fetal MRI biomarkers can be translated into predictive or clinical applications. Full article

Background: Acute transverse myelitis (ATM) is an inflammatory disorder of the spinal cord with heterogeneous etiologies, including autoimmune, infectious, paraneoplastic, and drug-induced causes. Tumor necrosis factor-alpha (TNF-α) inhibitors have been infrequently associated with inflammatory central nervous system events, including transverse myelitis. TNF-inhibitor-associated myelitis typically presents with short-segment lesions, a normal brain MRI, and partial responsiveness to corticosteroids. Longitudinally extensive transverse myelitis (LETM) and steroid-refractory cases are uncommon. Case Presentation: A 39-year-old woman with psoriatic arthritis treated with etanercept for two years presented with subacute progressive bilateral lower-extremity sensory loss and weakness. MRI revealed a T2 hyperintense spinal cord lesion extending from T11 to L1 with gadolinium enhancement, consistent with transverse myelitis, while brain MRI was normal. Cerebrospinal fluid analysis showed lymphocytic pleocytosis, elevated protein, oligoclonal bands, and increased kappa free light chains. Extensive infectious, metabolic, paraneoplastic, and autoimmune testing, including aquaporin-4 and MOG antibodies, was negative. Despite high-dose intravenous corticosteroids and the discontinuation of etanercept, the patient experienced clinical worsening with lesion expansion, meeting criteria for LETM, and developed urinary retention. She subsequently underwent plasma exchange, resulting in radiologic improvement and moderate clinical recovery. Conclusions: This case highlights an atypical presentation of TNF-inhibitor-associated myelitis characterized by a biphasic course, longitudinally extensive spinal cord involvement, steroid refractoriness, and responsiveness to plasma exchange. These features suggest either an unusually severe TNF-inhibitor-related inflammatory phenotype or a TNF-inhibitor-triggered antibody-mediated demyelinating process. Reports of TNF-inhibitor-associated myelitis evolving into longitudinally extensive, steroid-refractory disease remain limited, and this presentation may broaden the recognized clinical spectrum of TNF-α-related CNS inflammatory events. Close neurologic follow-up and heightened awareness of severe CNS complications associated with TNF-α inhibitors are warranted. Full article

When people interact, their actions reflect mood, attitude, and intention. Stern termed the affective qualities conveyed by actions, such as gentleness or rudeness, Vitality Forms (VFs). Previous research shows that children with autism spectrum disorder (ASD) differ from neurotypical (NT) peers in both perceiving and expressing these fundamental aspects of communication. It remains unclear whether these differences arise from structural or connectivity alterations in brain regions involved in VF processing. This study investigated structural and microstructural brain differences between children with ASD and NT peers, focusing on the VF-related network, which includes the dorso-central insula (DCI), premotor cortex (PM), middle cingulate cortex (MCC), and dorsolateral prefrontal cortex (DLPFC). Structural MRI data were collected from 60 right-handed boys aged 6–10 years (30 ASD, 30 NT), with diffusion MRI data available for a subset (20 ASD, 20 NT). A multimodal approach combined voxel-based morphometry (VBM), tract-based spatial statistics (TBSS), and probabilistic tractography. VBM revealed increased grey-matter volume in the PM, DLPFC, and MCC in the ASD group, with no differences in the DCI. TBSS showed white-matter microstructural alterations in premotor-related pathways. Probabilistic tractography further indicated atypical organization of tracts connecting the PM with the DLPFC, MCC, and DCI in children with ASD. Overall, the findings suggest atypical development of the premotor cortex and its associated white-matter connections in ASD, supporting theoretical accounts that link this network to altered processing of affective action dynamics during social interaction. Full article

Mild traumatic brain injury (mTBI) is typically associated with transient cognitive disturbance, particularly involving attention and new learning, with most patients demonstrating full recovery within weeks. Memory impairment in uncomplicated mTBI generally reflects reversible neurometabolic dysfunction and is limited to a brief period of post-traumatic amnesia and restricted retrograde loss surrounding the injury. However, a subset of patients develop persistent and disproportionate autobiographical memory disturbance that exceeds expected neuroanatomical limits and lacks structural correlates on neuroimaging. In rare but clinically challenging cases, this presentation may resemble extensive retrograde or identity-related amnesia. This review examines functional (dissociative) amnesia emerging after mTBI and proposes that concussion may act as a gateway condition facilitating the development of Functional Cognitive Disorder (FCD) in vulnerable individuals. We differentiate expected post-traumatic memory patterns from atypical selective impairment of autobiographical retrieval and clarify how distinct memory systems—episodic, autobiographical, semantic, and procedural—are differentially affected. We expand the two-hit hypothesis by integrating contemporary neurobiological evidence. The first hit comprises concussion-induced neurometabolic disturbance, glial activation, oxidative imbalance, and transient fronto-limbic dysregulation. The second hit may involve psychological stress, identity threat, maladaptive metacognitive processes, or persistent neuroinflammatory signalling, collectively resulting in functional inhibition of autobiographical memory retrieval despite preserved memory storage. Functional amnesia is conceptualised as a severe phenotype within the spectrum of functional cognitive disorder. We introduce a structured clinician-administered interview (SIFRA) to operationalise diagnostic features and support systematic assessment. This integrative framework reconciles neurological vulnerability with functional network dysregulation and provides a coherent basis for diagnosis and multidisciplinary management of persistent memory disturbance after mTBI. Full article

Pediatric neurological disorders comprise a highly heterogeneous group of conditions that together represent a substantial global public health burden. Many have a strong genetic basis and are associated with significant morbidity, premature mortality, and long-term disability, with far-reaching consequences for affected children, their families, and healthcare systems worldwide. Clinical heterogeneity is a hallmark of these disorders, as pathogenic variants in the same gene can give rise to diverse phenotypes with variable severity, age at onset, and disease course. In children, ongoing brain development and somatic growth further complicate diagnosis, often leading to nonspecific or atypical presentations that differ from classical adult neurological phenotypes. Advances in genetics and genomics have fundamentally transformed the understanding, diagnosis, and classification of pediatric neurological diseases. The widespread use of high-throughput sequencing, genome-wide association studies, and integrative bioinformatics approaches has enabled the rapid and precise identification of disease-associated genes, even in sporadic and complex conditions, facilitating earlier and more accurate diagnoses and highlighting the role of genetic background and gene–environment interactions in disease pathogenesis. Here we provide an overview of the genetic and genomic landscape of key pediatric neurological disorders with well-characterized molecular etiologies, including neuromuscular disorders, epilepsies, neurodevelopmental disorders, neurodegenerative diseases, and movement disorders. Current knowledge is synthesized with emphasis on clinical presentation, genetic architecture, and genotype–phenotype correlations. Gene-specific management strategies and emerging precision therapies are discussed for selected conditions, underscoring the central role of genetic diagnosis in guiding clinical decision-making and improving outcomes in affected children. Full article

Objective: To synthesize current evidence on the relationships between adolescent idiopathic scoliosis (AIS), stress-related mechanisms, neuroanatomical asymmetry, and mental disorders, and to propose an integrative conceptual framework describing their interaction. Materials and Methods: A comprehensive literature review was conducted using the PubMed, Web of Science, and Scopus databases. Search terms targeted the etiology and pathogenesis of adolescent idiopathic scoliosis, hemispheric lateralization, stress responses, body schema disturbances, and associated mental disorders. The review was reported in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) recommendations. A structured qualitative synthesis of 225 relevant publications was performed. Results: The analyzed studies revealed several complementary conceptual approaches to AIS pathogenesis. Emerging evidence suggests that atypical hemispheric lateralization, potentially associated with right-hemisphere (RH) dysfunction, may contribute to susceptibility to AIS. Such patterns of lateralization have been linked to specific stress-related coping strategies, including harm avoidance, as well as to disturbances of body schema and an increased prevalence of certain mental disorders. Gender-related differences in stress responses and in the development and progression of AIS were consistently reported across studies. Collectively, these findings support the hypothesis that neuropsychological and stress-related mechanisms, including phenomena described as the “distorting mirror effect”, may contribute to the persistence and progression of spinal deformity in vulnerable individuals. Conclusions: AIS appears to be a multifactorial condition in which atypical neuroanatomical asymmetry, stress-related processes, and altered body representation interact. This integrative perspective generates hypotheses suggesting that prevention and treatment strategies for AIS could benefit from incorporating approaches aimed at modulating stress responses and enhancing brain neuroplasticity. Further interdisciplinary studies integrating clinical, neuroimaging, and neurobiological methods are warranted to clarify underlying mechanisms. Full article

Background: Aortic dissection (AoD) is a life-threatening medical emergency characterized by the separation of the layers of the aortic wall. The typical clinical presentation of AoD includes intense thoracic pain in the anterior chest or interscapular region, often described as migratory and tearing in nature. However, in rare cases, AoD can present without classic signs but with neurological symptoms, including seizures. Case Presentation: A 60-year-old patient experienced a sudden loss of consciousness followed by a tonic–clonic seizure and subsequently developed right-sided weakness. He had a medical history of hypertension and smoking. Although the symptoms quickly resolved, the brain imaging revealed signs of an acute ischemic stroke located in the left hemisphere. The seizures resumed, blood D-dimer levels were found to be highly elevated, and subsequent thoracic and abdominal computed tomography angiography revealed the presence of AoD, which originated at the proximal part of the ascending aorta. The patient received symptomatic treatment to alleviate his symptoms and prevent complications and was quickly transferred for surgical intervention, resulting in a favorable outcome. Conclusions: This case demonstrates that a tonic–clonic seizure can be the first clinical manifestation of AoD. Such atypical symptoms highlight the diverse and misleading nature of AoD presentations, underscoring the challenges in the diagnostic process. This emphasizes the need for increased clinical vigilance when treating a patient experiencing their first seizure episode. Full article

Developmental Language Disorder (DLD) is associated with abnormalities in both intrinsic resting-state brain networks and task-evoked neural responses, yet direct electrophysiological evidence linking these levels remains limited. This study examined multi-level EEG markers in 21 typically developing children and 15 children with DLD across resting-state, a semantic matching task, and an auditory oddball task. Resting-state analyses revealed frequency-specific connectivity imbalances, reduced stability of intrinsic microstate dynamics, and atypical transitions between microstates in the DLD group. During the semantic matching task, DLD children showed weaker occipital P1 and N2 responses (100–300 ms) and lacked the right fronto-central difference wave (500–700 ms) observed in TD children. In the auditory oddball task, DLD children exhibited high-theta/low-alpha event-related desynchronization at left frontal electrodes (400–500 ms), in contrast to TD children. A machine learning framework integrating resting-state and task-based features discriminated DLD from TD children (test-set F1 = 70.3–80.0%) but showed limited generalizability, highlighting the constraints of small clinical samples. These findings support a translational neurophysiological signature for DLD, in which atypical intrinsic network organization constrains emergent neural computations, providing a foundation for future biomarker development and targeted intervention strategies. Full article

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by impairments in social interaction and communication, along with atypical behavioral patterns. Affected individuals often seem isolated in their inner world and exhibit particular sensory reactions. The World Health Organization has indicated a persistent increase in the global prevalence of autism, with approximately 1 in 127 persons affected worldwide. This study contributes to the growing research effort by presenting a comprehensive analysis of functional connectivity patterns for ASD prediction using rs-fMRI datasets. A novel approach was used for ASD identification using the ABIDE II dataset, based on functional networks derived from BOLD signals. The sparse functional brain connectome (Lean-NET) model is employed to construct subject-specific connectomes, from which local graph metrics are extracted to quantify regional network properties. Statistically significant features are selected using Welch’s t-test, then subjected to False Discovery Rate (FDR) correction and classified using a Support Vector Machine (SVM). Our experimental results demonstrate that locally derived graph metrics effectively discriminate ASD from typically developing (TD) subjects and achieve accuracy ranging from 70% up to 91%, highlighting the potential of graph learning approaches for functional connectivity analysis and ASD characterization. Full article

Sensory processing differences, reported in up to 97% of individuals with autism spectrum disorder (ASD), are increasingly recognized as a defining feature of the condition, shaping perception, cognition, and adaptive behavior. Atypical sensory responsivity, ranging from hyper- to hypo-reactivity and sensory seeking, emerges early in development and contributes to the clinical and neurobiological heterogeneity of autism. Alterations in neural connectivity, the balance of excitation and inhibition, and multisensory integration are thought to underlie these sensory profiles, influencing emotional regulation, attention, and social interaction. Sensory features also interact with co-occurring conditions such as anxiety, attention deficit hyperactivity disorder, and sleep and feeding difficulties, thereby shaping developmental trajectories and influencing adaptive behavior. Clinically, these sensory dysfunctions have a significant impact on daily participation and quality of life, extending their effects to family functioning. Understanding individual sensory phenotypes is therefore essential for accurate assessment and personalized intervention. Current therapeutic approaches include Sensory Integration Therapy, Sensory-Based Interventions, Sequential Oral Sensory Approach, and structured physical activity programs, often complemented by behavioral and mindfulness-based techniques. Emerging neuroplasticity-oriented methods for targeted modulation of sensory processing networks include neurofeedback and non-invasive brain stimulation. Overall, current evidence highlights the central role of sensory processing in ASD and underscores the need for multidisciplinary, individualized approaches to optimize developmental trajectories and enhance adaptive functioning. This review provides an updated synthesis of sensory processing in ASD, integrating neurobiological, developmental, and clinical evidence to highlight established knowledge, unresolved questions, and priorities for future research. Full article

Objectives: Atypical teratoid/rhabdoid tumors (ATRTs) are rare, malignant central nervous system (CNS) neoplasms that predominantly affect infants and young children. While ATRT arises throughout the CNS, its extracranial counterpart, malignant rhabdoid tumor, occurs in other organs. A single-institutional cohort is reviewed to map anatomic distribution of pediatric ATRTs and to integrate a literature review to contextualize ATRT histogenesis from anatomical and embryological perspectives. Methods: A retrospective review was conducted on a cohort of 50 pediatric patients with ATRT treated over 20 years. Demographic, surgical, and neuroimaging data were correlated to define tumor location, extent, and compartmental involvement. A focused literature review synthesized molecular subclassifications and proposed cells of origin/cytogenesis. Results: Of the 50 ATRTs, 18 (36%) were infratentorial, 15 (30%) supratentorial, 11 (22%) in the pineal region, and 6 (12%) in the spinal compartment. Among infratentorial tumors, 10 were centered in the fourth ventricle, with or without extension into the cerebellopontine angle (CPA) cistern; the remainder arose in the CPA. Among ATRTs of the cerebral hemispheres, 3 showed bi-hemispheric involvement crossing the falx cerebri. ATRTs of the pineal region predominantly originated from the superior medullary velum. These topographic data were corelated with embryological and molecular information available in the literature. Conclusions: ATRTs arise across diverse neuroanatomical compartments—including intraparenchymal, intraventricular, extra-axial, and extradural sites—underscoring biological heterogeneity. Inactivation of SMARCB1 is the defining molecular event and principal oncogenic driver, although the upstream mechanisms precipitating these alterations remain incompletely resolved. Molecular subgroups—ATRT-TYR, ATRT-SHH, and ATRT-MYC—display distinct age distributions and anatomic predilections, implicating developmental context in tumor initiation. The characteristic cellular admixture of rhabdoid cells with mesenchymal and/or epithelial differentiation, together with intra- and extra-axial and occasional extradural presentations, supports a model in which at least a subset of ATRTs may originate from neural crest-derived lineages, despite little or no neural crest contribution to brain parenchyma development. Neural plate border progenitors with bipotent features represent a plausible intraparenchymal cell of origin. Definitive resolution of these origins and the mechanisms of SMARCB1 disruption will require integrated approaches. Further investigations are warranted to clarify these mechanisms. Full article

Central nervous system (CNS) cryptococcosis caused by Cryptococcus neoformans is a severe opportunistic infection that primarily affects individuals with impaired cellular immunity. Although the classic presentation includes headache, fever, and meningeal signs, chronically immunosuppressed patients may develop atypical neuropsychiatric manifestations, leading to diagnostic delays. We report the case of a 53-year-old man with rheumatoid arthritis (RA) receiving long-term prednisolone and etanercept therapy, who presented with a 7-day history of depressive mood, anhedonia, social withdrawal, irritability, and progressive confusion. Neurological examination revealed disorientation without focal deficits. Brain imaging showed only mild cortical atrophy, and cerebrospinal fluid (CSF) analysis revealed lymphocytic pleocytosis, low glucose, and elevated protein levels. Multiplex PCR (FilmArray^®) of CSF identified Cryptococcus neoformans, CSF positive to C. neoformans. The patient was treated with liposomal amphotericin B followed by fluconazole, resulting in gradual improvement of both neurological and psychiatric symptoms. This case highlights an unusual presentation of CNS cryptococcosis in a non-HIV immunosuppressed patient with RA, emphasizing that acute psychiatric or cognitive changes can be the predominant manifestation. Clinicians should consider fungal infections in the differential diagnosis of acute neuropsychiatric symptoms in patients receiving chronic corticosteroid and biologic therapy. Early recognition and molecular diagnosis can facilitate timely antifungal treatment, potentially improving prognosis and reducing morbidity associated with delayed therapy. This report underscores the importance of awareness of atypical presentations of opportunistic infections in immunosuppressed populations. Full article

Background and Clinical Significance: Wilson disease is a rare autosomal recessive disorder of copper metabolism that can initially present with psychiatric symptoms, leading to delays in accurate diagnosis and treatment. Adult-onset cases may be misdiagnosed as primary psychiatric disorders, particularly when hepatic signs are subtle or absent. Early recognition is critical to prevent irreversible neurological and hepatic damage. Case Presentation: A 48-year-old Hispanic male developed persecutory delusions, cognitive decline, and ultimately catatonia over a three-year period. He was initially diagnosed with a primary psychiatric disorder and treated with antipsychotics, which caused severe extrapyramidal side effects. Further evaluation revealed markedly abnormal liver function tests, low serum ceruloplasmin, and elevated 24 h urinary copper excretion. Brain MRI showed characteristic findings of Wilson disease, and liver biopsy confirmed the diagnosis. The patient was started on trientine and zinc sulfate, but progressive hepatic dysfunction necessitated liver transplantation. Following a successful transplant, the patient experienced significant neurological and psychiatric recovery. Conclusions: This case underscores the importance of considering Wilson disease in patients presenting with atypical or treatment-resistant psychiatric symptoms, particularly when accompanied by abnormal liver function or intolerance to antipsychotics. Timely, multidisciplinary evaluation is essential to avoid misdiagnosis and initiate appropriate therapy. Early intervention can significantly improve both psychiatric and medical outcomes in Wilson disease. Full article

Background: SPATA5L1-related neurodevelopmental disorder is a recently described condition characterized by psychomotor delay, sensorineural hearing loss, and variable motor dysfunction. Because only a few cases have been reported, the full phenotypic spectrum remains poorly defined. Expanding clinical characterization is crucial for improving early diagnosis and targeted management. Case Presentation: We report a 24-month-old female with compound heterozygous SPATA5L1 variants c.1918C>T (p.Arg640Ter) and c.2066G>T (p.Gly689Val). She presented with global psychomotor delay, bilateral sensorineural hearing loss, strabismus, and craniofacial dysmorphism. Brain MRI showed cortical and white matter atrophy, delayed myelination, and a thin corpus callosum. Vojta neurodevelopmental assessment demonstrated an 11-month motor delay, abnormal responses in all seven Vojta postural reactions, and persistent primitive reflexes. Early EEG recordings were without significant changes, whereas abnormalities emerged later in the clinical course. Genetic testing confirmed the variants in trans. Management and Outcomes: Early rehabilitation including reflex locomotion therapy was initiated. The persistence of primitive reflexes, central hypotonia, and pathological postural reactions provided a coherent neuromotor profile and indicated a high vulnerability to atypical motor development, and do not rule out the possibility of later evolution toward a spastic–dystonic motor pattern. These findings, combined with neuroimaging abnormalities, refined the patient’s neuromotor phenotype and guided individualized therapeutic planning. Conclusions: This case expands the clinical and neurodevelopmental spectrum associated with SPATA5L1 variants and highlights the diagnostic value of integrating genomic sequencing with structured motor assessments. Early, multidimensional evaluation may improve recognition of rare neurodevelopmental disorders and support more precise prognostication and rehabilitation strategies. Full article

Background/Objective: Acute and chronic pain affect millions of individuals, yet there are currently no molecular imaging tools to directly assess pain-related mechanisms in the central nervous system (CNS). The voltage-gated sodium channel Na_V1.8 plays a pivotal role in neuropathic pain by increasing the excitability of nociceptive neurons following nerve injury or inflammation. In this work, we aimed to develop a novel positron emission tomography (PET) imaging probe for Na_V1.8 to facilitate noninvasive quantification of this target in the CNS and thereby advance our understanding of pain neurobiology. Methods: We selected the compound suzetrigine, a U.S. FDA-approved, highly selective non-opioid Na_V1.8 inhibitor, as the first candidate for a Na_V1.8-targeted PET tracer. The compound was first assessed using in silico docking and CNS multiparameter optimization (MPO) analysis to evaluate target binding and predicted brain penetrability. Radiolabeling was accomplished by O-methylation with [¹¹C]methyl iodide to yield [¹¹C]suzetrigine without structural modification. The tracer was then evaluated using in vitro binding assays, including autoradiography and saturation binding on rat brain tissues, to determine binding parameters (K_D, B_max), and using in vivo PET imaging in rats to assess brain uptake, time–activity curves (TACs), and tracer behavior under baseline and pretreatment conditions. Pretreatment was performed with unlabeled suzetrigine, the P-glycoprotein (P-gp) inhibitor verapamil, and the heterologous Na_V1.8 inhibitor A-803467. Results: In silico docking demonstrated favorable binding of suzetrigine to the Na_V1.8 active site, and the calculated CNS MPO score (>3.5) suggested adequate brain penetration. Radiochemical synthesis of [¹¹C]suzetrigine via O-methylation yielded a high decay-corrected radiochemical yield (19.2 ± 2.7%, n = 3), excellent purity (>98%, n = 3), and moderate molar activity (62.9 ± 51.8 MBq/nmol, n = 3). Autoradiography on rat brain tissue confirmed saturable and selective binding of [¹¹C]suzetrigine to Na_V1.8. Saturation binding assays revealed a B_max = 93 fmol/mg and a K_D = 0.1 nM, supporting the imageability of Na_V1.8 in the brain using this tracer. In vivo PET imaging in rats demonstrated rapid and sufficient brain uptake but revealed unexpected tracer behavior: signal intensity markedly increased following pretreatment with either unlabeled suzetrigine or the P-gp inhibitor verapamil, and showed a slight increase after pretreatment with the heterologous Na_V1.8 inhibitor A-803467. Detailed analysis of PET images, TACs, and normalized area-under-curve (AUC) values indicated that these atypical uptake patterns were primarily attributable to P-gp-mediated effects, although additional factors may also contribute. Conclusions: [¹¹C]Suzetrigine exhibits high affinity, good brain uptake, and selective target engagement in vitro, supporting its potential as a first-in-class Na_V1.8-PET tracer. However, in vivo performance is confounded by P-gp-mediated efflux and possibly other mechanisms that limit accurate quantification of Na_V1.8 in the living brain. These findings underscore the critical role of efflux transporters in CNS radiotracer development and highlight the need for design strategies that mitigate P-gp interaction when targeting ion channels in the brain. Future studies will include imaging under constant P-gp inhibition, arterial blood sampling for radiometabolite analysis and full kinetic modeling, and evaluation in non-human primates to assess translational feasibility. Full article