Search Results (379)

This study assessed the cross-modal agreement between spin-exchange relaxation-free magnetoencephalography (SERF-MEG) and conventional visual evoked potentials (VEPs) in patients with optic nerve injury using comparable pattern-reversal visual stimulation paradigms. Forty-five patients with optic neuritis (ON), ischemic optic neuropathy (ION), and traumatic optic neuropathy (TON) were enrolled, and a paired-eye design was applied to assess interocular electrophysiological changes between the affected and fellow eyes. Both modalities indicated consistent impairment of visual pathway function, reflected by reduced response amplitudes and prolonged latencies. For latency measures, MEG-derived M100 showed moderate directional concordance and a significant correlation with VEP P100, whereas amplitude measures demonstrated similar directional changes but limited quantitative correlations across modalities. Compared with the MaxP2P method, the channel-averaged method displayed higher stability and cross-modal concordance. These findings show that SERF-MEG can capture clinically relevant visual pathway impairment and may complement conventional VEP by providing additional information on cortical response patterns. Overall, SERF-MEG shows potential as an objective functional biomarker for neuro-ophthalmic assessment of optic nerve injury. Full article

Introduction: Biallelic pathogenic variants in DNAJC30 cause an autosomal recessive form of Leber hereditary optic neuropathy (LHONAR1), traditionally considered a mitochondrially transmitted disorder. The phenotypic spectrum of diseases linked to DNAJC30 includes isolated optic neuropathy, Leigh syndrome spectrum (LSS), and atypical LHON-plus. Case description: Here, we report a 13-year-old boy presenting symptoms of area postrema syndrome (APS), with recurrent vomiting, vertigo, nystagmus, and subacute visual deterioration with central scotoma. Ophthalmological examination revealed bilateral papilledema with telangiectatic vessels, while visual evoked potentials demonstrated severe bilateral optic pathway dysfunction. Brain magnetic resonance imaging (MRI) showed T2/FLAIR hyperintense lesions involving the area postrema and enhancement of the optic nerves, strongly suggesting seronegative neuromyelitis optica spectrum disorder (NMOSD). Extensive immunological and cerebrospinal fluid studies, including anti-aquaporin-4 (AQP4) and anti-MOG antibodies, were negative. High-dose corticosteroids and intravenous immunoglobulins resulted in only transient and incomplete improvement, followed by further visual decline. Additionally, laboratory tests detected elevated lactate plasma levels. Hence, whole-exome sequencing was performed, which identified a homozygous pathogenic DNAJC30 c.152A>G, p.(Tyr51Cys) variant, associated with LHONAR1. After initiation of idebenone therapy, the patient showed significant improvement in visual function, normalization of lactate levels, and complete resolution of the brainstem lesions on follow-up MRI. Conclusions: This case further expands the neuro-ophthalmic spectrum associated with DNAJC30 variants and suggests that DNAJC30-related disease may closely mimic seronegative NMOSD. We highlight that early genetic diagnosis is essential, as recognition of this mitochondrial etiology enables targeted therapy and may substantially improve clinical outcomes. Full article

Background: Understanding how humans perceive and represent themselves is central to cognitive neuroscience. Although self-face processing is well characterized, how distinct dimensions of the self, such as facial and creator identities, are neurally integrated remains largely unknown. Heartbeat-related self-expression and its underlying neural interactions remain unexplored. Methods: We simultaneously recorded EEG and ECG signals from 32 art students while they viewed self- and other-created portraits (of self and other). Results: The results revealed distinct processing pathways for facial identity and creator identity, while both self-related stimuli elicited special neural responses. Furthermore, their interaction emerged in early visual evoked potentials (188–344 ms) and late heartbeat-evoked potentials (344–596 ms). Conclusions: These findings indicate that the self is modulated by visual and interoceptive signals, offering new insights into the neural mechanisms of selfhood in artistic practice. Full article

The educational pathway for expertise in intraoperative neurophysiological monitoring (IONM) is complex and lengthy, requiring a solid foundation in neuroscience, neurophysiology, and neuroanatomy. It also demands direct familiarity with a broad range of neurosurgical scenarios, including supratentorial, infratentorial, and spinal procedures, gained through exposure to at least ten distinct surgical approaches. Intraoperative neurophysiology must be tailored to each patient’s preoperative assessments. It relies on a variety of methods to collect, analyze, and report neurophysiological signals that are relevant to the surgical procedure. Despite its importance, there remains a substantial shortage of training tools designed to support realistic practice and skill development. To address this gap, we developed a comprehensive framework (ION-Sim) that integrates all laboratory testing modalities and adapts them to the operating room environment. ION_sim supports the simulation and analysis of spontaneous EEG and EMG activity, a wide range of evoked potentials, and intraoperative stimulus–response testing protocols. The framework provides a unified environment for practicing, testing, and validating the core neurophysiological procedures employed during neurosurgical interventions. In addition, it incorporates a robust data-management architecture, maintaining a database with system setups, user profiles, educational performance metrics, and automatically generating reports. This structure enables the longitudinal tracking of objective skill acquisition and facilitates standardized assessments of trainee progress. ION_Sim is distributed both as a ready-to-use application, suitable for direct integration into teaching and training programs, and as a modular scientific library. Through its dedicated APIs, users can design customized configurations, create novel simulation scenarios, and extend the platform to support additional research or educational objectives. It is available upon request for educational purposes and is open-source and released under the GNU General Public License, ensuring transparency, reproducibility, and long-term accessibility for the scientific and clinical communities. Full article

Background/Objectives: Visual evoked potential (VEP) P100 maximum latency is known to predict fatigue and cognition in multiple sclerosis (MS). However, the relationship between VEP and neurological (impairment)/neuropsychological status is not well understood in MS. Therefore, the aim of the present prospective cross-sectional study was to investigate associations among VEP, neurological impairment, and neuropsychological status in MS. Methods: The study included 25 subjects with primary progressive MS (PPMS), with a median EDSS score of 4.5, and 30 control subjects. Neurological status of PPMS subjects was evaluated with the Expanded Disability Status Scale (EDSS), while neuropsychological assessment included the Symbol Digit Modalities Test (SDMT), Nine-Hole Peg Test (9HPT), Fatigue Severity Scale (FSS), Depression, Anxiety and Stress Scale (DASS-21), and Multiple Sclerosis Impact Scale (MSIS-29). Statistical analysis included group comparisons, Spearman correlations, multivariable linear regression analyses, bidirectional stepwise selection, and a parsimonious multivariable model. Results: PPMS subjects had significantly prolonged P100 maximum latencies (p < 0.01) compared to control subjects, as well as significantly poorer performance on the 9HPT (p < 0.01) and higher fatigue scores (FSS; p < 0.01). In multivariable analyses within the PPMS group, disease duration was independently associated with the EDSS (p = 0.009), whereas neuropsychological measures were intercorrelated (ρ > 0.45) and associated with the EDSS at intermediate stages of model selection. P100 maximum latency showed a positive but non-significant association after adjustment for sex and disease duration in the parsimonious model, which explained approximately 49% of the variance in the EDSS. Conclusions: The findings provide insight into the complex interplay among neurophysiological (VEP), neuropsychological and neurological status in MS. Full article

This study aimed to characterize cortical dysfunction and frequency-specific network reorganization following optic nerve injury using spin-exchange relaxation-free magnetoencephalography (SERF-MEG), and to assess the potential of MEG-derived multiscale features as sensitive functional biomarkers for clinical evaluation. In this prospective case–control study, SERF-MEG recordings were acquired during a pattern-reversal visual stimulation paradigm. Time-domain evoked components (M100/M135), global electrophysiological indices, energy-based metrics, and alpha- and beta-band phase-based functional connectivity were extracted. Network topology was quantified using graph-theoretical measures, including global and local efficiency, clustering coefficient, and assortativity. Group-level differences between patients and healthy controls were statistically analyzed. Patients showed significantly reduced M100/M135 amplitudes, prolonged M100 latency, and a lower early-component energy ratio. Functional connectivity was significantly decreased in the alpha and beta bands, accompanied by reduced global and local efficiency, mean strength, and clustering coefficient. Seed-based analyses revealed reduced connectivity predominantly in occipito-parietal and occipito-temporal pathways. SERF-MEG provides sensitive identification of cortical- and network-level functional impairments following optic nerve damage. MEG has significant clinical potential for disease diagnosis and therapy monitoring, providing a novel objective assessment tool for neuro-ophthalmological disorders. Full article

Improving the decoding accuracy and information transfer rate (ITR) of steady-state visual evoked potential brain–computer interface (SSVEP-BCI) systems, while enhancing cross-subject generalization and reducing calibration cost, is essential for practical deployment. This study proposes an end-to-end framework that integrates adaptive filtering with semi-supervised domain adaptation. The framework incorporates a Gabor adaptive filter bank (G-AFB) to optimize time–frequency representations and extract features matched to individual neural responses. It also introduces a three-stage semi-supervised domain-adversarial neural network (TriS-DANN), which combines unsupervised pre-alignment and supervised fine-tuning to align cross-subject feature distributions and enable lightweight calibration. On the 1.0 s public benchmark dataset, G-AFB-tCNN achieved 89.13% accuracy, a 4.63 percentage-point improvement over its conventional filter-bank counterpart. On the 0.4 s in-house dataset, G-AFB-tCNN achieved 91.85% accuracy, a 3.22 percentage-point improvement over the conventional fixed filter bank. In transfer learning, TriS-DANN reached 86.60% accuracy using 0.4 s segments extracted from the stimulation period and only 23.07% of the available target-domain training/calibration trials, demonstrating higher efficiency and stability than conventional fine-tuning. These results support the proposed framework as a feasible route toward reliable, low-calibration SSVEP-BCI systems. Full article

Steady-state visual evoked potential-based brain–computer interfaces (SSVEP-BCIs) are widely applied in non-invasive brain–computer interaction, yet traditional single-frequency coding suffers from scarce frequency resources and degraded accuracy in multi-target tasks. The partitioned backlight mode (PB-M) supports SSVEP spatial coding, while systematic investigations on its inherent backlight crosstalk are still lacking. This study develops a PB-M-based SSVEP-BCI system to explore crosstalk mechanisms. Each participant completed 90 valid trials with 18 stimuli and five repetitions each. The results verify inter-partition crosstalk, which can reduce recognition accuracy under narrow frequency intervals and non-isolated layouts, and gaze position can modulate non-target SSVEP responses. Classification accuracy was calculated by valid correct trial ratios, and the information transfer rate (ITR) was computed using standard BCI formulas, yielding 87.50% accuracy and 48.75 bits/min ITR. Full exhaustive classification testing across all 18 stimulus targets was not implemented, where core classification validation was performed on partially selected targets. The proposed frequency reuse strategy shows promising potential to improve SSVEP-BCI performance based on empirical experimental data, providing valid references for multi-target BCI design. Full article

Background/Objectives: Monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway are effective drugs for migraine prevention. The worsening of symptoms after treatment discontinuation has raised the question of whether these agents are associated with sustained central neurophysiological adaptation. This study investigated treatment-associated changes in sensory processing and cortical network efficiency during preventive treatment with CGRP monoclonal antibodies (mAbs). Methods: Twenty-two patients with episodic migraine (21 female, 46.2 ± 13.8 years) and 22 age- and sex-matched healthy controls underwent visual and somatosensory evoked-potential (VEP, SSEP) assessments and quantitative electroencephalography (qEEG). Patients were investigated before treatment initiation (V0) and after 3 months of CGRP mAb treatment (V3). Healthy controls were assessed once. Results: The lack of habituation of VEPs at V0 shifted toward habituation at V3 following treatment with CGRP mAbs (Δslope: −0.37 ± 0.83, p = 0.03). VEP habituation at V3 no longer differed significantly from controls. SSEP amplitudes remained stable and did not differ significantly between groups across the study interval. Exploratory qEEG parameters indicated a less efficient cortical network organization at V0 that was no longer significantly different from controls at V3. Conclusions: Three months of CGRP mAb treatment was associated with a partial normalization of selected neurophysiological parameters, particularly VEP habituation and exploratory qEEG network measures. Given the study design and small sample size, these findings indicate adaptive changes in multi-domain processing, yet these should not be overinterpreted as proof of disease modification. Full article

Non-arteritic anterior ischemic optic neuropathy (NAION) is a leading cause of sudden vision loss, yet no effective therapy exists to preserve retinal ganglion cells (RGCs) after ischemic injury. Nostoc commune (NC), an edible cyanobacterium with established antioxidant and anti-inflammatory activities, has emerged as a potential functional bioresource with relevance to ocular health. Here, we investigated the therapeutic effects of a crude aqueous extract of NC using a rodent model of anterior ischemic optic neuropathy (rAION). NC treatment significantly improved RGC survival, reduced apoptosis, attenuated macrophage and microglial activation (ED-1, Iba1), suppressed proinflammatory cytokine expression (IL-6), enhanced the reparative marker Ym1+2, and preserved optic-nerve myelination. Functionally, NC administration restored visual signaling as demonstrated by improved Flash Visual Evoked Potential amplitudes. Immunoblot analysis showed increased phosphorylation of PI3K/AKT/mTOR/p70S6K signaling components in retinal tissue following NC treatment. Proteomic profiling further demonstrated that NC extract comprises a coordinated repertoire of phycobiliproteins, antioxidant enzymes, and stress-response proteins that may collectively contribute to its biological effects. Together, these findings suggest that Nostoc commune extract may serve as a promising functional food-derived candidate for protecting RGCs and preserving visual function following ischemic optic neuropathy. Further studies are required to identify its active constituents, optimize formulation strategies, and evaluate its translational potential. Full article

Background/Objectives: Steady-State Visual Evoked Potential-based Brain–Computer Interfaces face a critical trade-off between system accuracy and user visual fatigue. To address this challenge, the objective of this study was to determine how the spatial manipulation of stimulus size modulates the full spectral dynamics of the Electroencephalogram, encompassing both the periodic oscillatory response and the aperiodic (1/f) background noise. Methods: Twenty-two healthy subjects completed a sustained visual attention task using a competitive stimulus paradigm (20 Hz and 30 Hz) presented in three spatial dimensions (Small, Medium, and Big). Parieto-occipital brain signals were decomposed using the spectral parameterization algorithm (SpecParam) to extract frequency-specific visually evoked response power and the aperiodic slope, while visual fixation was continuously monitored via eyetracking. Results: Increasing stimulus size induced a statistically significant gain in the power of the attended signal (Target) without increasing the response of the peripheral distractor. Simultaneously, larger stimuli produced a significant increase in the aperiodic slope during 20 Hz attention and visual rest, suggesting increased cortical inhibition and a reduction in broadband neural activity. This aperiodic modulation was not observed at 30 Hz. Conclusions: The improvement in Signal-to-Noise Ratio with increasing stimulus size arises from a dual neurophysiological mechanism: enhancement of the periodic evoked response together with a reduction in background neural noise. Full article

Background: Graft-versus-host disease is the most common complication after allogeneic hematopoietic stem cell transplantation. While ocular graft-versus-host disease typically manifests as dry eye syndrome and anterior segment involvement, posterior segment complications are rare. Previously reported posterior segment complications in graft-versus-host disease have been limited to acute presentations with significant functional visual impairment. Methods: A 41-year-old man developed progressive retinal nerve fiber layer and ganglion cell layer loss four years after allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia. The patient had established chronic graft-versus-host disease with cutaneous involvement and ocular surface disease. Results: Despite preserved visual acuity and visual fields, and only subtle functional involvement on visual evoked potentials, optical coherence tomography revealed significant reduction in retinal nerve fiber layer thickness and ganglion cell layer. Magnetic resonance imaging showed no optic nerve or brain abnormalities. Conclusions: This case describes an uncommon presentation of chronic, subclinical posterior segment involvement in chronic GVHD and suggests that optical coherence tomography may detect progressive structural retinal changes in the absence of clinically evident visual impairment, supporting its potential role in longitudinal monitoring. Full article

With population aging, motor vehicle accidents involving older drivers have increased. Age-related cognitive decline affects driving performance; however, the underlying neural mechanisms remain unclear. This scoping review explored neurophysiological characteristics associated with driving in older adults, including those at risk of dementia. Following PRISMA-ScR guidelines, we searched PubMed, Scopus, and CINAHL for studies examining driving-related neurophysiological measures in older adults aged ≥60 years. Twelve studies were included. Findings converge on load-dependent neural compensation failure: older adults maintain driving performance under low-to-moderate demands, but compensatory mechanisms break down under high cognitive load. Electroencephalography (EEG) studies revealed blunted midfrontal theta upregulation during high-load conditions, associated with reduced steering precision and delayed responses. Event-related potential studies demonstrated that reduced P3b amplitude was associated with missed braking responses and that abnormal visual evoked potentials in Alzheimer’s disease predicted unfit-to-drive classifications. fNIRS studies during driving-related tasks and an fMRI study using a laboratory-based visual task consistently showed prefrontal hyperactivation in older adults. Although some older adults maintained comparable performance to younger adults, the brain–behavior associations observed in younger adults were absent, suggesting that this hyperactivation does not necessarily serve a functional compensatory role. Combined with EEG evidence of impaired oscillatory modulation, these findings suggest that prefrontal hyperactivation does not necessarily compensate for diminished neural synchronization under high-load conditions. Neurophysiological markers hold promise for fitness-to-drive assessments. Future research should employ high-load scenarios and multimodal neuroimaging to verify prefrontal compensatory mechanisms. Full article

Electroencephalography (EEG)-based brain–computer interface (BCI) systems are often affected by substantial inter-subject variability. These differences cause distribution shifts between the source domain and the target domain. As a result, the decoder’s generalization to unseen subjects is reduced. In online steady-state visual evoked potentials (SSVEP)-based BCI systems, the decoder must not only cope with inter-subject distribution shifts but also adapt rapidly. However, most existing methods require accumulating multiple trials before adaptation, which increases data acquisition and update latency and thus limits their practicality in online settings. To address these challenges, this study focuses on a practically important but insufficiently explored setting, which is unlabeled inter-subject SSVEP decoding with single-trial online adaptation, where immediate adaptation is required and multi-trial accumulation is impractical. For this setting, this study proposes a low-latency test-time adaptation algorithm that combines trial-wise online Euclidean alignment, entropy minimization, and pseudo-label frequency regularization. This integration supports single-trial adaptation under online constraints, without requiring target labels or trial buffering, thereby reducing adaptation latency while mitigating inter-subject distribution shift. Experiments on two public datasets using four backbone models show that the proposed method achieves an average accuracy of 75.70%, outperforming the non-adaptive baseline by 3.88%. These results indicate that the proposed method improves inter-subject SSVEP decoding accuracy and shows potential for online BCI applications. Full article

Background and Objectives: Visual evoked potentials (VEPs) are a simple, noninvasive method for detecting subclinical visual pathway involvement in multiple sclerosis. This study investigated the frequency of VEP abnormalities and their associations with baseline clinical, radiological, and cerebrospinal fluid (CSF) features in treatment-naïve patients with clinically isolated syndrome (CIS) or early relapsing-remitting multiple sclerosis (RRMS) without prior optic neuritis. Materials and Methods: We retrospectively reviewed newly diagnosed, treatment-naïve CIS/early RRMS patients evaluated between January 2022 and July 2024 who underwent CSF analysis. Pattern-reversal VEPs were recorded under standardized conditions. VEP abnormalities were analyzed as any or bilateral, and associations were assessed using group comparisons and multivariable logistic regression. Results: In 101 patients (mean age 31.8 ± 9.7 years; 72% female; median EDSS 1.0), latency prolongation occurred in 69 (42 any,27 bilateral) and amplitude reduction in 33 (22 any, 11 bilateral). Among patients with latency prolongation, both the number of OCB bands and the IgG index were higher (bilateral p = 0.032; any p = 0.007). In multivariable analysis, male sex (p = 0.032) and pyramidal/brainstem-onset presentation (p = 0.006) were independently associated with any amplitude reduction; neither was associated with latency abnormalities. Conclusions: VEP abnormalities are common early in the disease, even without a history of optic neuritis. Male sex and pyramidal/brainstem-onset presentation were associated with reduced amplitude, suggesting that amplitude decrease may reflect early tissue dysfunction and may be related to adverse baseline clinical features. Associations between intrathecal immune activation and prolonged latency may indicate subclinical demyelination of the visual pathways related to inflammatory activity. Larger longitudinal studies are needed to clarify the clinical significance of VEP abnormalities in early RRMS. Full article