Publications by authors named "Ryuichiro Hashimoto"

Article Synopsis
  • 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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The human auditory system includes discrete cortical patches and selective regions for processing voice information, including emotional prosody. Although behavioral evidence indicates individuals with autism spectrum disorder (ASD) have difficulties in recognizing emotional prosody, it remains understudied whether and how localized voice patches (VPs) and other voice-sensitive regions are functionally altered in processing prosody. This fMRI study investigated neural responses to prosodic voices in 25 adult males with ASD and 33 controls using voices of anger, sadness, and happiness with varying degrees of emotion.

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Background: Altruistic cooperation (AC) is essential in human social interactions. Previous studies have investigated AC-related behavior in children with autism spectrum disorder (ASD), revealing that there is considerable individual variability in the behavior. However, this issue is still largely unexplored especially in the adult population.

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Developmental stuttering is a speech disfluency disorder characterized by repetitions, prolongations, and blocks of speech. While a number of neuroimaging studies have identified alterations in localized brain activation during speaking in persons with stuttering (PWS), it is unclear whether neuroimaging evidence converges on alterations in structural integrity of white matter and functional connectivity (FC) among multiple regions involved in supporting fluent speech. In the present study, we conducted coordinate-based meta-analyses according to the PRISMA guidelines for available publications that studied fractional anisotropy (FA) using tract-based spatial statistics (TBSS) for structural integrity and the seed-based voxel-wise FC analyses.

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According to the operational diagnostic criteria, psychiatric disorders such as schizophrenia (SZ), bipolar disorder (BD), major depressive disorder (MDD), and autism spectrum disorder (ASD) are classified based on symptoms. While its cluster of symptoms defines each of these psychiatric disorders, there is also an overlap in symptoms between the disorders. We hypothesized that there are also similarities and differences in cortical structural neuroimaging features among these psychiatric disorders.

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Differential diagnosis is sometimes difficult in practical psychiatric settings, in terms of using the current diagnostic system based on presenting symptoms and signs. The creation of a novel diagnostic system using objective biomarkers is expected to take place. Neuroimaging studies and others reported that subcortical brain structures are the hubs for various psycho-behavioral functions, while there are so far no neuroimaging data-driven clinical criteria overcoming limitations of the current diagnostic system, which would reflect cognitive/social functioning.

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Article Synopsis
  • The study investigates the role of increased excitatory signals in autism, focusing on elevated levels of glutamate and its relation to astrocyte activation and dopamine signaling.
  • Using imaging techniques, researchers compared 18 adults with high-functioning autism to 20 typically developed individuals, finding significant increases in glutamate, glutamine, and myo-inositol levels in the autism group.
  • Results indicate a correlation between glutamine levels and dopamine receptor binding, suggesting that heightened excitation and astrocyte activity may contribute to autism's symptoms by disrupting normal inhibitory dopamine signaling.
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Individuals with autism spectrum disorder (ASD) often show limited empathy (poor recognition of others' emotions) and high alexithymia (poor recognition of own emotions and external thinking), which can negatively impact their social functioning. Previous experimental studies suggest that alterations in cognitive flexibility play key roles in the development of these characteristics in ASD. However, the underlying neural mechanisms that link cognitive flexibility and empathy/alexithymia are still largely unknown.

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Article Synopsis
  • * A study involving 730 Japanese adults aimed to develop a generalizable neuromarker for ASD, successfully identifying relevant functional connections that differentiate individuals with ASD from typically developing controls (TDCs).
  • * The research found that the developed neuromarker is applicable across various age groups and countries, while also indicating a biological connection between ASD and schizophrenia (SCZ), but less so with major depressive disorder (MDD).
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Autism spectrum disorder (ASD) is a lifelong condition, and its underlying biological mechanisms remain elusive. The complexity of various factors, including inter-site and development-related differences, makes it challenging to develop generalizable neuroimaging-based biomarkers for ASD. This study used a large-scale, multi-site dataset of 730 Japanese adults to develop a generalizable neuromarker for ASD across independent sites (U.

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Aim: Increasing evidence suggests that psychiatric disorders are linked to alterations in the mesocorticolimbic dopamine-related circuits. However, the common and disease-specific alterations remain to be examined in schizophrenia (SCZ), major depressive disorder (MDD), and autism spectrum disorder (ASD). Thus, this study aimed to examine common and disease-specific features related to mesocorticolimbic circuits.

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Our motor system uses sensory feedback to keep desired performance. From this view, motor fluctuation is not simply 'noise' inevitably caused in the nervous system but would play a role in generating variations to explore better outcomes via sensory feedback. Vocalization system offers a good model for studying such sensory-motor interactions since we regulate vocalization by hearing our own voice.

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Groups are essential elements of society, and humans, by nature, commonly manifest intergroup bias (i.e., behave more positively toward an ingroup member than toward an outgroup member).

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People make flexible decisions across a wide range of contexts to resolve social or moral conflicts. Individuals with autism spectrum disorder (ASD) frequently report difficulties in such behaviors, which hinders the flexibility in changing strategies during daily activities or adjustment of perspective during communication. However, the underlying mechanisms of this issue are insufficiently understood.

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Article Synopsis
  • Machine learning classifiers using resting-state fMRI are being used to explore the links between brain circuits and psychiatric disorders.
  • A large-scale database was created, including neuroimaging data from 993 patients and 1,421 healthy individuals, along with demographic details.
  • To ensure consistent data, nine healthy participants underwent brain imaging across 12 different scanners, and four datasets have been published for research use.
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Background: Better life satisfaction (LS) is associated with better psychological and psychiatric outcomes. To the best of our knowledge, no studies have examined prediction models for LS.

Methods: Using resting-state functional magnetic resonance imaging (R-fMRI) data from the Human Connectome Project (HCP) Young Adult S1200 dataset, we examined whether LS is predictable from intrinsic functional connectivity (iFC).

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Large-scale neuroimaging data acquired and shared by multiple institutions are essential to advance neuroscientific understanding of pathophysiological mechanisms in psychiatric disorders, such as major depressive disorder (MDD). About 75% of studies that have applied machine learning technique to neuroimaging have been based on diagnoses by clinicians. However, an increasing number of studies have highlighted the difficulty in finding a clear association between existing clinical diagnostic categories and neurobiological abnormalities.

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Introduction: Previous studies on metacognitive ability were explored using self-report questionnaires that are difficult to adequately measure and evaluate when the capacity for self-reference is undeveloped. This study aimed to validate the Congruency-based Metacognition Scale (CMS) to measure metacognition and the feeling of confidence abilities and to investigate the development of metacognition during adolescence.

Methods: The CMS was administered to 633 child-parent pairs in Japan (child, mean age = 16.

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Individuals with autism spectrum disorder (ASD) are found to have difficulties in understanding speech in adverse conditions. In this study, we used noise-vocoded speech (VS) to investigate neural processing of degraded speech in individuals with ASD. We ran fMRI experiments in the ASD group and a typically developed control (TDC) group while they listened to clear speech (CS), VS, and spectrally rotated VS (SRVS), and they were requested to pay attention to the heard sentence and answer whether it was intelligible or not.

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Symptoms of autism spectrum disorder and attention-deficit/hyperactivity disorder often co-occur. Among these, sensory impairment, which is a core diagnostic feature of autism spectrum disorder, is often observed in children with attention-deficit/hyperactivity disorder. However, the underlying mechanisms of symptoms that are shared across disorders remain unknown.

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Many studies have highlighted the difficulty inherent to the clinical application of fundamental neuroscience knowledge based on machine learning techniques. It is difficult to generalize machine learning brain markers to the data acquired from independent imaging sites, mainly due to large site differences in functional magnetic resonance imaging. We address the difficulty of finding a generalizable marker of major depressive disorder (MDD) that would distinguish patients from healthy controls based on resting-state functional connectivity patterns.

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Background: Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) have high rates of co-occurrence and share atypical behavioral characteristics, including sensory symptoms. The present diffusion tensor imaging (DTI) study was conducted to examine whether and how white matter alterations are observed in adult populations with developmental disorders (DD) and to determine how brain-sensory relationships are either shared between or distinct to ASD and ADHD.

Methods: We collected DTI data from adult population with DD (a primary diagnosis of ASD: n = 105, ADHD: n = 55) as well as age- and sex-matched typically developing (TD) participants (n = 58).

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  • An amendment to the original paper has been released.
  • This amendment includes updates or corrections to the content.
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Article Synopsis
  • The study explored dopamine (DA) and noradrenaline (NA) neurotransmissions in adults with autism spectrum disorder (ASD) using advanced PET imaging with two different radioligands.
  • No significant differences were found in DA D1 receptor or noradrenaline transporter binding between individuals with ASD and neurotypical controls.
  • However, within the ASD group, DA D1 receptor binding showed negative correlations with attention to detail and positive correlations with emotion perception ability, suggesting a complex relationship between these neurotransmitters and ASD traits.
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