Publications by authors named "Kunii N"

Article Synopsis
  • Gamma oscillation regularity (GOR) reflects the synchronization of inhibitory interneurons, while cortico-cortical evoked potentials (CCEPs) indicate local cortical excitability, particularly related to excitatory pyramidal cells.
  • In a study involving five patients with mesial temporal lobe epilepsy (MTLE) who had intracranial electrodes implanted, researchers quantified GOR and CCEP responses near stimulation sites to visualize inhibitory and excitatory cortical activities, finding higher activity levels in epileptogenic regions.
  • By combining GOR and CCEP data, a new metric called the excitatory and inhibitory (EI) index was developed, which improved specificity in predicting the epileptogenic zone compared to using GOR or CCEP alone,
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  • A case report of primary dural lymphoma in a 51-year-old man, who developed it after treatment for subdural empyema, highlighting the link between chronic inflammation and lymphoma.
  • The patient initially presented with symptoms that suggested a chronic subdural hematoma, but further investigation led to the diagnosis of B-cell lymphoma.
  • The case emphasizes the need to consider lymphoma as a possible cause of subdural hematomas when there is no clear underlying pathology.
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  • Sound frequency and duration play crucial roles in how our brain detects prediction errors, helping us respond swiftly to changing auditory environments.
  • An electrocorticography study with 13 participants revealed significant activation in certain brain regions during frequency and duration tasks, highlighting their connection to prediction errors.
  • Differences in the brain's response patterns between duration and frequency tasks suggest distinct processing mechanisms, which may help explain certain auditory processing challenges in psychiatric disorders.
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Epileptogenic zones (EZs), where epileptic seizures cease after resection, are localized by assessing the seizure-onset zone using ictal electroencephalography (EEG). Owing to the difficulty in capturing unpredictable seizures, biomarkers capable of identifying EZs from interictal EEG are anticipated. Recent studies using intracranial EEG have identified several potential candidate biomarkers for epileptogenicity.

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  • Auditory sensory processing occurs in a hierarchical manner involving key brain areas like the primary auditory cortex and the superior temporal gyrus, which help create predictions about sounds.
  • A new auditory paradigm called "cascade roving" was developed to study how these brain regions respond to unexpected sounds, analyzing data from epilepsy patients.
  • Results showed that while the superior temporal gyrus responded to these unexpected sounds, the inferior frontal gyrus had longer and broader responses, revealing distinct characteristics in auditory processing compared to typical testing methods.
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Background And Objectives: Risk factors for vasovagal reaction (VVR) have been extensively studied. With knowledge of the relative importance of these risk factors for VVR, collection staff could take care of blood donors from the same standpoint, leading to improved donor safety. We therefore developed a scoring system to predict VVR, which incorporates registration information.

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  • Neurofeedback (NF) may improve memory and its specific application to the medial temporal lobe (MTL) is being researched to better understand its effects on memory function.* -
  • A memory NF system was developed using intracranial electrodes to observe neural activity in the MTL during memory tasks, showing promising changes in neural signals and memory task performance among three patients with drug-resistant epilepsy.* -
  • Results indicate that NF can potentially modulate MTL activity and enhance memory encoding, but further research is needed to refine the NF system and confirm its effects on memory enhancement.*
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  • The study examines the potential of neurofeedback (NF) as a complementary treatment for preserving memory function in patients undergoing mesial temporal lobe (MTL) removal due to intractable epilepsy.
  • The researchers developed a memory NF system that used intracranial electrodes to provide feedback on neural activity during memory tasks, focusing on the language-dominant side of the MTL.
  • Results showed changes in neural activity — with increased theta power and decreased fast beta and gamma power — in one patient, marking the first report of NF potentially modulating MTL activity related to memory encoding, despite not correlating with improved memory function.
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There has been tremendous progress in artificial neural networks (ANNs) over the past decade; however, the gap between ANNs and the biological brain as a learning device remains large. With the goal of closing this gap, this paper reviews learning mechanisms in the brain by focusing on three important issues in ANN research: efficiency, continuity, and generalization. We first discuss the method by which the brain utilizes a variety of self-organizing mechanisms to maximize learning efficiency, with a focus on the role of spontaneous activity of the brain in shaping synaptic connections to facilitate spatiotemporal learning and numerical processing.

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  • A multicenter retrospective cohort study in Japan investigated the impact of the COVID-19 pandemic on epilepsy care from January 2019 to December 2020, analyzing data such as outpatient visits, EEGs, and surgeries.
  • Findings showed a decrease in outpatient visits and EEG studies and a drastic increase in telemedicine use, with significant negative effects on admissions and procedures during periods of higher COVID-19 cases and a state of emergency.
  • The study highlights the substantial disruption to epilepsy care caused by the pandemic, corroborating previous research and emphasizing the extent of these changes.
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Decoding the inner representation of a word meaning from human cortical activity is a substantial challenge in the development of speech brain-machine interfaces (BMIs). The semantic aspect of speech is a novel target of speech decoding that may enable versatile communication platforms for individuals with impaired speech ability; however, there is a paucity of electrocorticography studies in this field. We decoded the semantic representation of a word from single-trial cortical activity during an imageability-based property identification task that required participants to discriminate between the abstract and concrete words.

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Background: Vagus nerve stimulation (VNS) is an established palliative surgical treatment for refractory epilepsy. Recently, pairing VNS with rehabilitation received growing attention for their joint effect on neural plasticity. However, objective biological measurements proving the interaction between VNS effects and cortical recruitment are lacking.

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Neurofeedback through visual, auditory, or tactile sensations improves cognitive functions and alters the activities of daily living. However, some people, such as children and the elderly, have difficulty concentrating on neurofeedback for a long time. Constant stressless neurofeedback for a long time may be achieved with auditory neurofeedback using music.

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  • Gamma oscillations reflect key brain processes related to perception and cognition, involving specific types of interneurons and are notably altered in disorders like schizophrenia and autism.
  • The auditory steady-state response (ASSR) serves as a key measure of these gamma oscillations, showing reduction in patients with neuropsychiatric conditions, though the underlying neural mechanisms remain unclear.
  • A study using high-density electrocorticography in epilepsy patients revealed that ASSR exhibits a complex, frequency-tuned distribution across various cortical regions, indicating differentiated processing pathways for auditory information.
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Objective: In long-term video-monitoring, automatic seizure detection holds great promise as a means to reduce the workload of the epileptologist. A convolutional neural network (CNN) designed to process images of EEG plots demonstrated high performance for seizure detection, but still has room for reducing the false-positive alarm rate.

Methods: We combined a CNN that processed images of EEG plots with patient-specific autoencoders (AE) of EEG signals to reduce the false alarms during seizure detection.

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Background: Delayed syncopal-type complications are infrequent among blood donors, but sometimes have critical consequences, such as severe injury. We retrospectively investigated the characteristics of donors with delayed syncopal-type complications or falls.

Study Design And Methods: We defined a delayed reaction (DR) as syncopal-type complications occurring >20 min after needle removal.

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Article Synopsis
  • Auditory mismatch negativity (MMN) is a crucial response indicating how our brain processes unexpected sounds, typically occurring before we consciously pay attention to them.
  • Previous research hinted that MMN might just be a result of N1 adaptation, which involves basic auditory processing, leading to confusion about their distinct roles.
  • The study used electrocorticography on epilepsy patients to show that MMN can be differentiated from N1 adaptation, revealing that MMN is related to more complex auditory processing in broader brain areas.
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  • The study focuses on the rising rates of oropharyngeal squamous cell carcinoma (OPSCC) largely linked to human papillomavirus (HPV) and analyzes the disease's molecular subgroup stratification for better understanding of its clinicopathological features.
  • 170 OPSCC cases were examined using DNA methylome analysis and targeted sequencing, resulting in the identification of four distinct epigenotypes based on methylation levels: HPV(+) high-methylation (OP1), HPV(+) intermediate-methylation (OP2), HPV(-) intermediate-methylation (OP3), and HPV(-) low-methylation (OP4).
  • The study found significant differences in prognosis among the epigenotypes, with OP1 showing the
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Although aberrations in the number and function of glutamate AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors are thought to underlie neuropsychiatric disorders, no methods are currently available for visualizing AMPA receptors in the living human brain. Here we developed a positron emission tomography (PET) tracer for AMPA receptors. A derivative of 4-[2-(phenylsulfonylamino)ethylthio]-2,6-difluoro-phenoxyacetamide radiolabeled with C ([C]K-2) showed specific binding to AMPA receptors.

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Background: Due to the strong tumoricidal activities of activated natural killer T (NKT) cells, invariant NKT cell-based immunotherapy has shown promising clinical efficacy. However, suppressive factors, such as regulatory T cells (Tregs), may be obstacles in the use of NKT cell-based cancer immunotherapy for advanced cancer patients. Here, we investigated the suppressive effects of Tregs on NKT cells and the underlying mechanisms with the aim to improve the antitumor activities of NKT cells.

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Article Synopsis
  • * Recent studies indicate that ASSR alterations may serve as a significant link to understanding E/I imbalance and could reflect the clinical progression of these disorders.
  • * Research involving animal models suggests that specific synaptic interactions in the brain contribute to the regulation of E/I balance, which impacts gamma oscillation generation and provides insight into the underlying mechanisms of neuropsychiatric diseases.
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Introduction: Epileptologists could benefit from a diagnosis support system that automatically detects seizures because visual inspection of long-term electroencephalograms (EEGs) is extremely time-consuming. However, the diversity of seizures among patients makes it difficult to develop universal features that are applicable for automatic seizure detection in all cases, and the rarity of seizures results in a lack of sufficient training data for classifiers.

Methods: To overcome these problems, we utilized an autoencoder (AE), which is often used for anomaly detection in the field of machine learning, to perform seizure detection.

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Article Synopsis
  • * The auditory oddball paradigm allows for the measurement of MMN without requiring behavioral responses, making it applicable across different species, including rodents and nonhuman primates, enhancing our understanding of its mechanisms.
  • * Recent studies focus on MMN's neural computations and mechanisms, and future research may lead to innovative treatment strategies by linking basic and clinical knowledge about schizophrenia.
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