A5006729002- Advanced MRI Techniques and Applications
- Functional Brain Connectivity Studies
- Advanced Neuroimaging Techniques and Applications
- Fetal and Pediatric Neurological Disorders
- Neuroscience and Neuropharmacology Research
- Medical Imaging Techniques and Applications
- Lanthanide and Transition Metal Complexes
- MRI in cancer diagnosis
- Thermoregulation and physiological responses
- Optical Imaging and Spectroscopy Techniques
- Neural dynamics and brain function
- Glioma Diagnosis and Treatment
- Liver Disease Diagnosis and Treatment
- Visual perception and processing mechanisms
- Metabolism and Genetic Disorders
- Education Systems and Policy
- Heart Rate Variability and Autonomic Control
- Lipid metabolism and biosynthesis
- Cardiac Imaging and Diagnostics
- Experimental Learning in Engineering
- Cell Image Analysis Techniques
- Atomic and Subatomic Physics Research
- Primate Behavior and Ecology
- Advanced NMR Techniques and Applications
- Action Observation and Synchronization
RIKEN Center for Biosystems Dynamics Research
2018-2025
Systems Dynamics (United States)
2022
RIKEN
2020
Oulu University Hospital
2014-2019
University of Oulu
2014-2019
University of Eastern Finland
2010-2014
National Institutes for Quantum Science and Technology
2008
The theory on the glymphatic convection mechanism of cerebrospinal fluid holds that cardiac pulsations in part pump from peri-arterial spaces through extracellular tissue into peri-venous facilitated by aquaporin water channels. Since pulses cannot be sole propulsion, we searched for additional human brain with ultra-fast magnetic resonance encephalography. We detected three types physiological mechanisms affecting cerebral pulsations: cardiac, respiratory, and very low frequency pulsations....
We present distinct patterns of neurite distribution in the human cerebral cortex using diffusion magnetic resonance imaging (MRI). analyzed both high-resolution structural (T1w and T2w images) MRI data 505 subjects from Human Connectome Project. Neurite distributions were evaluated orientation dispersion density (NODDI) model, optimized for gray matter, mapped onto cortical surface a method weighted towards mid-thickness to reduce partial volume effects. The estimated was high somatosensory...
Chemical exchange saturation transfer (CEST) and spin-locking (SL) experiments were both able to probe the process between protons of nonequivalent chemical environments. To compare characteristics CEST SL approaches in study effects, we performed at varied pH concentrated metabolite phantoms with exchangeable amide, amine, hydroxyl 9.4 T. Our results show that: (i) on-resonance is most sensitive exchanges intermediate-exchange regime detect amine on a millimolar concentration scale....
Macaque monkeys are an important animal model where invasive investigations can lead to a better understanding of the cortical organization primates including humans. However, tools and methods for noninvasive image acquisition (e.g. MRI RF coils pulse sequence protocols) data preprocessing have lagged behind those developed To resolve structural functional characteristics smaller macaque brain, high spatial, temporal, angular resolutions combined with signal-to-noise ratio required ensure...
T1-weighted divided by T2-weighted (T1w/T2w) myelin maps were initially developed for neuroanatomical analyses such as identifying cortical areas, but they are increasingly used in statistical comparisons across individuals and groups with other variables of interest. Existing T1w/T2w contain radiofrequency transmit field (B1+) biases, which may be correlated these interest, leading to potentially spurious results. Here we propose two empirical methods correcting biases using either explicit...
Diffusion tensor imaging (DTI) and neurite orientation dispersion density (NODDI) are widely used models to infer microstructural features in the brain from diffusion-weighted MRI. Several studies have recently applied both increase sensitivity biological changes, however, it remains uncertain how these measures associated. Here we show that cortical distributions of DTI NODDI associated depending on choice b-value, a factor reflecting strength diffusion weighting gradient. We analyzed...
Psychiatric and neurological disorders are afflictions of the brain that can affect individuals throughout their lifespan. Many magnetic resonance imaging (MRI) studies have been conducted; however, imaging-based biomarkers not yet well established for diagnostic therapeutic use. This article describes an outline planned study, Brain/MINDS Beyond human MRI project (BMB-HBM, FY2018 ~ FY2023), which aims to establish clinically-relevant with multi-site harmonization by collecting data from...
Recent methodological advances in MRI have enabled substantial growth neuroimaging studies of non-human primates (NHPs), while open data-sharing through the PRIME-DE initiative has increased availability NHP data and need for robust multi-subject multi-center analyses. Streamlined acquisition analysis protocols would accelerate improve these efforts. However, consensus on minimal standards pipelines imaging remains to be established, particularly studies. Here, we draw parallels between...
Mapping the vascular organization of brain is great importance across various domains basic neuroimaging research, diagnostic radiology, and neurology. However, intricate task precisely mapping vasculature regions cortical layers presents formidable challenges, resulting in a limited understanding neurometabolic factors influencing brain’s microvasculature. Addressing this gap, our study investigates whole-brain volume using ferumoxytol-weighted laminar-resolution multi-echo gradient-echo...
Localising accurate brain regions needs careful evaluation in each experimental species due to their individual variability. However, the function and connectivity of areas is commonly studied using a single-subject cranial landmark-based stereotactic atlas animal neuroscience. Here, we address this issue small primate, common marmoset, which increasingly widely used systems We developed non-invasive multi-modal neuroimaging-based targeting pipeline, accounts for intersubject anatomical...
Abstract Feedback connections play a major role in many theories of brain function. Previous studies feedback to early visual areas have mainly concentrated on the representation central fields. Here, injections tracers at different eccentricities V1 and V2 revealed retinotopically organized feedback. Peripheral projections from 15 that are not labeled by injections. Connection strengths for majority vary significantly with eccentricity systematic fashion respect distance origin; whereas...
Abstract Cortical areas have traditionally been defined by their distinctive layer cyto- and/or myelo- architecture using postmortem histology. Recent studies delineated many measuring overall cortical myelin content and its spatial gradients the T1w/T2w ratio MRI in living primates, including humans. While of areal transitions might benefit from profile this myelin-related contrast, a significant confound is Gibbs’ ringing artefact, which produces signal fluctuations resembling layers....
The aim of the present work was to validate and optimize adiabatic T1ρ T2ρ mapping for in vivo measurements articular cartilage at 3 Tesla (T).Phantom experiments were systematically performed on a 3T clinical system evaluate sequences using hyperbolic secant HS1 HS4 pulses. R1ρ R2ρ relaxation rates studied as function agarose chondroitin sulfate concentration pulse duration. Optimal protocol determined by imaging two volunteers varying sequence parameters, successively applied eight...
Night monkeys (Aotus) are the only genus of within Simian lineage that successfully occupy a nocturnal environmental niche. Their behavior is supported by their sensory organs' distinctive morphological features; however, little known about evolutionary adaptations in regions cerebral cortex. Here, we investigate this question exploring cortical organization night using high-resolution in-vivo brain MRI and comparative cortical-surface T1w/T2w myeloarchitectonic mapping. Our results show...
Our previous study has shown that prenatal exposure to X-ray irradiation causes cerebral hypo-perfusion during the postnatal development of central nervous system (CNS). However, source and its impact on CNS remains unclear. The present developed an automatic analysis method determine mean red blood cell (RBC) speed through single microvessels imaged with two-photon microscopy in cortex rats prenatally exposed (1.5 Gy).We obtained a RBC (0.9±0.6 mm/sec) ranged from 0.2 4.4 mm/sec 121 vessels...
Diffusion-weighted (DW) functional magnetic resonance imaging (fMRI) signal changes have been noted as a promising marker of neural activity. Although there is no agreement on the origin, blood oxygen level dependent (BOLD) effect has figured one most likely sources. In order to investigate possible BOLD and non-BOLD contributions signal, DW fMRI was performed normal volunteers using sequence with two echo-planar acquisitions after pulsed-gradient spin-echo. Along amplitude (ΔS/S) measured...
We found novel types of parenchymal functional magnetic resonance imaging (fMRI) signals in the rat brain during large increases metabolism. Cortical spreading depression (CSD), a self-propagating wave cellular activation, is associated with several pathologic conditions such as migraine and stroke. It was used paradigm to evoke transient neuronal depolarization leading enhanced energy consumption. Activation CSD investigated using spin-lock (SL), diffusion, blood oxygenation level-dependent...
Mapping the vascular organization of brain is great importance across various domains basic neuroimaging research, diagnostic radiology, and neurology. However, intricate task precisely mapping vasculature regions cortical layers presents formidable challenges, resulting in a limited understanding neurometabolic factors influencing brain's microvasculature. Addressing this gap, our study investigates whole-brain volume using ferumoxytol-weighted laminar-resolution multi-echo gradient-echo...
Abstract T1-weighted divided by T2-weighted (T1w/T2w) myelin maps were initially developed for neuroanatomical analyses such as identifying cortical areas, but they are increasingly used in statistical comparisons across individuals and groups with other variables of interest. Existing T1w/T2w contain radiofrequency transmit field (B1+) biases, which may be correlated these interest, leading to potentially spurious results. Here we propose two empirical methods correcting biases using either...