Publications by authors named "Tsuyoshi Araki"

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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  • The gamma-band auditory steady-state response (ASSR) is a brain signal related to hearing and attention, which is found to be weaker in people with schizophrenia.
  • The study looked at how this weaker signal connects to changes in brain white matter, especially in areas on the right side of the brain.
  • Results showed that healthy people had a good connection between the gamma-band ASSR and white matter, but people with schizophrenia didn't show the same connection, suggesting that their brain networks might not work as well.
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Previous studies reported decreased glutamate levels in the anterior cingulate cortex (ACC) in non-treatment-resistant schizophrenia and first-episode psychosis. However, ACC glutamatergic changes in subjects at high-risk for psychosis, and the effects of commonly experienced environmental emotional/social stressors on glutamatergic function in adolescents remain unclear. In this study, adolescents recruited from the general population underwent proton magnetic resonance spectroscopy (MRS) of the pregenual ACC using a 3-Tesla scanner.

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Gamma oscillations, thought to arise from the activity of ɣ-aminobutyric acid (GABA)ergic interneurons, have potential as a biomarker for schizophrenia. Gamma-band auditory steady-state responses (ASSRs) are notably reduced in both chronic and early-stage schizophrenia patients. Furthermore, alterations in gamma-band ASSRs have been demonstrated in animal models through translational research.

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Adolescence is a critical period for psychological difficulties. Auditory mismatch negativity (MMN) and gamma-band auditory steady-state response (ASSR) are representative electrophysiological indices that mature during adolescence. However, the longitudinal association between MMN/ASSR and psychological difficulties among adolescents remains unclear.

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Several animal models of schizophrenia and patients with chronic schizophrenia have shown increased spontaneous power of gamma oscillations. However, the most robust alterations of gamma oscillations in patients with schizophrenia are reduced auditory-oscillatory responses. We hypothesized that patients with early-stage schizophrenia would have increased spontaneous power of gamma oscillations and reduced auditory-oscillatory responses.

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Objectives: This study aimed to examine the prospective association among objectively measured average working hours (AWHs), frequency of long working hours (FLWHs; defined as ≥205 working hours/month (≥45 hours/week)) for 6 months, and workers' self-reported psychological and physical health.

Methods: The study included 15 143 workers from 5 Japanese companies. We collected monthly attendance records over 6 months before distributing a questionnaire survey on psychological/physical stress responses and work-related demographics.

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  • The study aimed to create and validate a new scale for measuring email addiction tendency and its effects on behavior and brain structure.
  • Researchers found that higher email addiction scores were linked to lower nonverbal reasoning abilities and higher severity of depression symptoms.
  • Additionally, the study discovered a positive correlation between email addiction tendency and increased gray matter volume in the left rostrolateral prefrontal cortex, suggesting potential impacts on mental health.
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The soil is a rich ecosystem where many ecological interactions are mediated by small molecules, and in which amoebae are low-level predators and also prey. The social amoeba has a high genomic potential for producing polyketides to mediate its ecological interactions, including the unique 'Steely' enzymes, consisting of a fusion between a fatty acid synthase and a chalcone synthase. We report here that further increases its polyketide potential by using the StlB Steely enzyme, and a downstream chlorinating enzyme, to make both a chlorinated signal molecule, DIF-1, during its multi-cellular development, and a set of abundant polyketides in terminally differentiated stalk cells.

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  • In the social amoeba Dictyostelium discoideum, the polyketide MPBD plays a vital role in regulating cAMP signaling for cell aggregation and spore maturation.
  • The polyketide synthase StlA is responsible for the biosynthesis of MPBD and is conserved across major groups of social amoebas.
  • Research in Polysphondylium violaceum showed that StlA is essential for cell aggregation but not for spore maturation, and MPBD can reverse aggregation defects in StlA knockout mutants while chemotaxis remains unaffected.
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The detrimental effects of high-level mercury exposure on the central nervous system as well as effects of low-level exposure during early development have been established. However, no previous studies have investigated the effects of mercury level on brain morphometry using advance imaging techniques in young adults. Here, utilizing hair analysis which has been advocated as a method for biological monitoring, data of regional gray matter volume (rGMV), regional white matter volume (rWMV), fractional anisotropy (FA) and mean diffusivity (MD), cognitive functions, and depression among 920 healthy young adults in Japan, we showed that greater hair mercury levels were weakly but significantly associated with diminished cognitive performance, particularly on tasks requiring rapid processing (speed measures), lower depressive tendency, lower rGMV in areas of the thalamus and hippocampus, lower rWMV in widespread areas, greater FA in bilaterally distributed white matter areas overlapping with areas of significant rWMV reductions and lower MD of the widely distributed gray and white matter areas particularly in the bilateral frontal lobe and the right basal ganglia.

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  • The study investigates how changes in clinical symptoms relate to quality of life in individuals at ultra-high risk for psychosis and those with recent-onset psychotic disorders.
  • Researchers followed up with participants over a period ranging from 6 months to less than 5 years, assessing symptoms and quality of life using established measurement scales.
  • Results show that higher levels of anxiety/depression at the start were linked to poorer quality of life later, while improvements in these symptoms were associated with better quality of life outcomes.
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Background: Problematic alcohol use (PAU) after natural disasters is an unignorable public health issue. However, the long-term trajectory and course of PAU after an earthquake disaster remain unknown.

Methods: The Higashi-Matsushima cohort study was conducted between 2012 (time 1) and 2019 (time 8) in areas affected by the Great East Japan Earthquake in 2011.

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The excellence of the brain is its robustness under various types of noise and its flexibility under various environments. However, how the brain works is still a mystery. The critical brain hypothesis proposes a possible mechanism and states that criticality plays an important role in the healthy brain.

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The structural and functional brain characteristics associated with the excessive use of the internet have attracted substantial research attention in the past decade. In current study, we used voxel-based morphometry (VBM) and multiple regression analysis to assess the relationship between internet addiction tendency (IAT) score and regional gray and white matter volumes (rGMVs and rWMVs) and brain activity during a WM task in a large sample of healthy young adults (n = 1,154, mean age, 20.71 ± 1.

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Birth order is a crucial environmental factor for child development. For example, later-born children are relatively unlikely to feel secure due to sibling competition or diluted parental resources. The positive effect of being earlier-born on cognitive intelligence is well-established.

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How work burden affects physical and mental health has already been studied extensively; however, many issues have remained unexamined. In 2017, we commenced a prospective cohort study of workers at companies in Japan, with a follow-up period of 5-10 years, in order to investigate the current situation of overwork-related health outcomes. From 2017 to 2020, a target population of 150,000 workers across 8 companies was identified.

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Purpose: We aimed to examine the prospective associations of monthly working hours measured in a month, the 6-month averaged hours, and the frequency of long working hours (≥ 205 h/month) during the past 6 months with health indicators.

Methods: This study included 6,806 Japanese company workers (response rate = 86.6%).

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It has been hypothesized that a higher genetic risk of bipolar disorder (BD) is associated with greater creativity. Given the clinical importance of bipolar disorder and the importance of creativity to human society and cultural development, it is essential to reveal their associations and the neural basis of the genetic risk of bipolar disorder to gain insight into its etiology. However, despite the previous demonstration of the associations of polygenic risk score (PRS) of BD and creative jobs, the associations of BD-PRS and creativity measured by the divergent thinking (CMDT) and regional gray matter volume (rGMV) as well as regional white matter volume (rWMV) have not been investigated.

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  • The study investigates the relationship between the reactive hyperemia index (RHI), fatigue, and sleep in healthy hospital workers, noting that low RHI is linked to cardiovascular (CV) risks.
  • Measurements taken included RHI via peripheral arterial tonometry (PAT), reported fatigue levels using a visual analog scale (VAS), and hours of sleep, with notable differences observed before and after work shifts.
  • Results showed fatigue levels were higher after duty and sleep duration was longer before duty, yet RHI remained similar; low RHI correlated with higher fatigue scores, but no significant relationship was found when controlling for blood pressure and heart rate variability.
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Objective: Although brain structural studies have demonstrated the neural correlates of neuroticism, the outcomes are not easily identified because of the various possible brain regions involved, low statistical power (low number of subjects), and brain structural measures available, such as mean diffusivity (MD), which are more suitable than standard regional measures of grey and white-matter volume (rGMV, rWMV) and fractional anisotropy (FA). We hypothesized that neuroticism neural correlates could be detected by MD and differentially identified using other measures. We aimed to visualize the neural correlates of neuroticism.

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  • Lead exposure is toxic and particularly harmful to the central nervous system, but its specific effects on brain microstructure and function had not been thoroughly studied before this research.
  • The study analyzed data from 920 young adults, revealing that higher levels of lead in hair samples are weakly linked to changes in brain activity during memory tasks and alterations in the brain’s white matter structure.
  • Participants with increased lead levels also showed poorer performance in cognitive tests and higher impulsivity, suggesting that even low levels of lead exposure can have subtle but significant effects on brain function and behavior.
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Although it is known that health is not merely the absence of disease, the positive aspects of mental health have been less comprehensively researched compared with its negative aspects. Subjective well-being (SWB) is one of the indicators of positive psychology, and high SWB is considered to benefit individuals in multiple ways. However, the neural mechanisms underlying individual differences in SWB remain unclear, particularly in terms of brain microstructural properties as detected by diffusion tensor imaging.

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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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