282 results match your criteria: "The University of Tokyo Institutes for Advanced Study[Affiliation]"

Aging in a weighted ensemble of excitable and self-oscillatory neurons: The role of pairwise and higher-order interactions.

Chaos

January 2025

International Research Center for Neurointelligence, The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Bunkyo Ku, Tokyo 113 8654, Japan.

We investigate the aging transition in networks of excitable and self-oscillatory units as the fraction of inherently excitable units increases. Two network topologies are considered: a scale-free network with weighted pairwise interactions and a two-dimensional simplicial complex with weighted scale-free pairwise and triadic interactions. Without triadic interactions, the aging transition from collective oscillations to oscillation death (inhomogeneous stationary states) can occur either suddenly or through an intermediate state of partial oscillation.

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Owing to their rapid cooling rate and hence loss-limited propagation distance, cosmic-ray electrons and positrons (CRe) at very high energies probe local cosmic-ray accelerators and provide constraints on exotic production mechanisms such as annihilation of dark matter particles. We present a high-statistics measurement of the spectrum of CRe candidate events from 0.3 to 40 TeV with the High Energy Stereoscopic System, covering 2 orders of magnitude in energy and reaching a proton rejection power of better than 10^{4}.

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Increased structural covariance of cortical measures in individuals with an at-risk mental state.

Prog Neuropsychopharmacol Biol Psychiatry

November 2024

Department of Neuropsychiatry, University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama city, Toyama 930-0194, Japan; Research Center for Idling Brain Science, University of Toyama, 2630 Sugitani, Toyama city, Toyama 930-0194, Japan.

An anomalous pattern of structural covariance has been reported in schizophrenia, which has been suggested to represent connectome changes during brain maturation and neuroprogressive processes. It remains unclear whether similar differences exist in a clinical high-risk state for psychosis, and if they are associated with a prodromal phenotype and/or later psychosis onset. This multicenter magnetic resonance imaging study cross-sectionally examined structural covariance in a large at-risk mental state (ARMS) sample with different outcomes.

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MCGAE: unraveling tumor invasion through integrated multimodal spatial transcriptomics.

Brief Bioinform

November 2024

Lingang Laboratory, Building 8, 319 Yueyang Road, Xuhui District, Shanghai 200031, China.

Spatially Resolved Transcriptomics (SRT) serves as a cornerstone in biomedical research, revealing the heterogeneity of tissue microenvironments. Integrating multimodal data including gene expression, spatial coordinates, and morphological information poses significant challenges for accurate spatial domain identification. Herein, we present the Multi-view Contrastive Graph Autoencoder (MCGAE), a cutting-edge deep computational framework specifically designed for the intricate analysis of spatial transcriptomics (ST) data.

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Mismatch negativity (MMN) has gained attention as a biomarker for psychosis and a translational intermediate phenotype in animal models of psychosis, including rodents and non-human primates. MMN has been linked to global functioning (Global Assessment of Functioning [GAF] score) and prognosis (psychosis onset or remission), suggesting that MMN reflects activities beyond auditory processing alone. This review examines the 45-year history of MMN from the perspective of psychiatric researchers and discusses current advances in computational and translational research on MMN, summarizing the current understanding of the MMN generation mechanism.

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Article Synopsis
  • - The study investigates the link between rare copy number variations (CNVs) in synaptic genes and bipolar disorder (BD) in a Japanese population, using genome hybridization techniques on nearly 2,000 BD patients and 2,760 controls.
  • - Results indicate a strong association between the RNF216 gene and BD, with significant findings also related to postsynaptic membrane components, suggesting these genetic factors contribute to BD risk.
  • - The findings enhance understanding of BD's genetic underpinnings, highlighting the importance of CNVs in gene regions that may influence the disorder's development.
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  • Aberrant salience processing is a potential mechanism that might explain psychiatric symptoms in schizophrenia, as seen in abnormal gaze patterns when individuals view images.
  • A study involving 1012 participants compared gaze behaviors, revealing that individuals with schizophrenia had gaze trajectories influenced more by visual salience than healthy individuals, particularly in orientation salience.
  • The research also indicated that abnormal salience processing varies across different psychiatric disorders, with schizophrenia showing the strongest effects, followed by bipolar disorder, major depressive disorder, and autism spectrum disorder, linking salience abnormalities to the severity of psychotic symptoms.
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  • Autism spectrum disorder (ASD) is a complex lifelong condition, and this study aimed to create a classifier using resting-state fMRI from a large group of 730 Japanese adults to identify its neural and biological features.
  • The developed classifier showed effectiveness in differentiating individuals with ASD from neurotypical controls across various countries, including the US and Belgium, and it also applied to children and adolescents.
  • Importantly, the study found that the classifier identified crucial functional connections related to social interaction difficulties and neurotransmitter activity, and it linked ASD with similar neurobiological factors seen in ADHD and schizophrenia, enhancing understanding of related mental health disorders.
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Direct Collapse Supermassive Black Holes from Relic Particle Decay.

Phys Rev Lett

August 2024

Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095-1547, USA.

We investigate the formation of high-redshift supermassive black holes (SMBHs) via the direct collapse of baryonic clouds, where the unwanted formation of molecular hydrogen is successfully suppressed by a Lyman-Werner (LW) photon background from relic particle decay. We improve on existing studies by dynamically simulating the collapse, accounting for the adiabatic contraction of the DM halo, as well as the in situ production of the LW photons within the cloud which reduce the impact of the cloud's shielding. We find a viable parameter space where the decay of either some of the dark matter or all of a subdominant decaying species successfully allows direct collapse of the cloud to a SMBH.

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Article Synopsis
  • Genetically encoded fluorescent sensors are being enhanced to assess cortical activity in non-human primates, allowing for detailed measurements of brain dynamics.* -
  • The Automated Robotic Virus injection System (ARViS) was developed to facilitate the precise delivery of biosensors across different cortical areas, utilizing image recognition to avoid blood vessels and enabling precise micropipette insertion.* -
  • ARViS demonstrated its effectiveness by successfully injecting biosensors into 266 sites in a marmoset's frontoparietal cortex and enabling advanced imaging techniques to observe cortical activity.*
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Dynamic and Static Workout of In Vitro Skeletal Muscle Tissue through a Weight Training Device.

Adv Healthc Mater

December 2024

Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.

Enhancing muscle strength through workouts is a key factor in improving physical activity and maintaining metabolic profiles. The controversial results concerning the impacts of weight training often arise from clinical experiments that require controlled experimental conditions. In this study, a weight training system for a muscle development model is presented, which is capable of performing weight training motions with adjustable weight loads.

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Article Synopsis
  • The 2022 global outbreak of mpox (formerly known as monkeypox) and its 2023 sporadic cases underscored the need for effective nonpharmaceutical interventions like case isolation.
  • A new modeling framework was created to analyze how long infected individuals remain infectious based on their viral load, revealing that viral shedding can vary significantly from 23 to 50 days.
  • The study found that while existing symptom-based isolation guidelines are generally effective, switching to a testing-based rule could minimize unnecessary isolation after individuals are no longer infectious.
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  • Sensorimotor learning involves changes in neuronal activity in the premotor (PM) and primary motor cortex (M1) of primates, as studied through calcium imaging in common marmosets during a reaching task.
  • During the learning process, the dorsorostral PM demonstrated earlier peak activity compared to the dorsocaudal PM and M1, with increased reaction times in pull trials closely correlating with PMdr activity.
  • The dorsocaudal PM and M1 maintained stable representation of movements, while PMdc neurons adjusted their preferred movement direction based on push trial performance, highlighting the transition from dynamic tuning in PMdc to stable motor representation in M1 during learning.
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Article Synopsis
  • Neuroimaging databases for neuro-psychiatric disorders provide valuable data for researchers to explore diseases, develop machine learning models, and redefine understanding of these conditions.* ! -
  • A review identified 42 global MRI datasets totaling 23,293 samples from patients with various disorders, including mood, developmental, schizophrenia, Parkinson's, and dementia.* ! -
  • Improved governance and addressing technical issues of these databases are essential for sharing data across borders, aiding in understanding, diagnosing, and creating early interventions for neuro-psychiatric disorders.* !
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Correlations of brain structure with the social behavior of 15q11-13 duplication mice, an animal model of autism.

Neurosci Res

December 2024

Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8655, Japan. Electronic address:

Article Synopsis
  • Duplication of chromosome 15q11-13 is linked to autism spectrum disorder (ASD) and was studied in a mouse model known as 15q dup mice.
  • The study involved behavioral tests for anxiety and social interactions, alongside MRI scans, to explore the connection between brain structure and behavior in these mice.
  • Findings showed that 15q dup mice exhibited higher anxiety levels and varied social behaviors, with a correlation found between lower sociability and reduced gray matter in a specific brain region, highlighting the complexities of ASD's behavioral diversity.
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Discrepancies in self-rated and observer-rated depression severity may underlie the basis for biological heterogeneity in depressive disorders and be an important predictor of outcomes and indicators to optimize intervention strategies. However, the neural mechanisms underlying this discrepancy have been understudied. This study aimed to examine the brain networks that represent the neural basis of the discrepancy between self-rated and observer-rated depression severity using resting-state functional MRI.

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Alzheimer's disease is characterized by cognitive impairment and progressive brain atrophy. Recent human neuroimaging studies reported atypical anatomical and functional changes in some regions in the default mode network in patients with Alzheimer's disease, but which brain area of the default mode network is the key region whose atrophy disturbs the entire network activity and consequently contributes to the symptoms of the disease remains unidentified. Here, in this case-control study, we aimed to identify crucial neural regions that mediated the phenotype of Alzheimer's disease, and as such, we examined the intrinsic neural timescales-a functional metric to evaluate the capacity to integrate diverse neural information-and grey matter volume of the regions in the default mode network using resting-state functional MRI images and structural MRI data obtained from individuals with Alzheimer's disease and cognitively typical people.

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Article Synopsis
  • Developmental synapse elimination is essential for forming mature neural circuits, particularly in the cerebellum of neonatal mice where Purkinje cells initially connect with multiple climbing fibers.
  • By postnatal day 20, all climbing fiber synapses except one are eliminated, with heterosynaptic interactions between climbing fibers and parallel fibers playing a key role in this process.
  • The study finds that the deletion of AMPA receptors in granule cells disrupts the elimination of climbing fiber synapses, highlighting the importance of parallel fiber activity, which may enhance synapse elimination by activating mGlu1 receptors in Purkinje cells and NMDA receptors in molecular layer interneurons.
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  • The study analyzed 5804 days of Super-Kamiokande data from 1996 to 2018 to detect variations in solar ^{8}B neutrino flux.
  • The researchers utilized a five-day interval measurement approach and employed maximum likelihood and Lomb-Scargle methods to find any periodic modulations.
  • They found a significant modulation related to Earth's elliptical orbit around the Sun, with measurements of eccentricity and perihelion shift aligning with astronomical data.
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Aims: Schizophrenia (SZ) is a brain disorder characterized by psychotic symptoms and cognitive dysfunction. Recently, irregularities in sharp-wave ripples (SPW-Rs) have been reported in SZ. As SPW-Rs play a critical role in memory, their irregularities can cause psychotic symptoms and cognitive dysfunction in patients with SZ.

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Human induced pluripotent stem cell-derived cardiac muscle rings for biohybrid self-beating actuator.

Lab Chip

July 2024

Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 113-8656, Japan.

Cardiac muscle, a subtype of striated muscle composing our heart, has garnered attention as a source of autonomously driven actuators due to its inherent capability for spontaneous contraction. However, conventional cardiac biohybrid robots have utilized planar (2D) cardiac tissue consisting of a thin monolayer of cardiac myotubes with a thickness of 3-5 μm, which can generate a limited contractile force per unit footprint. In this study, 3D cardiac muscle rings were proposed as robotic actuator units.

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Reward-seeking behavior is frequently associated with risk of punishment. There are two types of punishment: positive punishment, which is defined as addition of an aversive stimulus, and negative punishment, involves the omission of a rewarding outcome. Although the medial prefrontal cortex (mPFC) is important in avoiding punishment, whether it is important for avoiding both positive and negative punishment and how it contributes to such avoidance are not clear.

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Background: The recent emergence of targeted radionuclide therapy has increased the demand for imagers capable of visualizing pharmacokinetics in developing radiopharmaceuticals in the preclinical phase. Some radionuclides emit hard x-rays and gamma-rays below 100 keV, in which energy range the performance of conventional NaI scintillators is poor. Multipinhole collimators are also used for small animal imaging with a good spatial resolution but have a limited field of view (FOV).

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