Publications by authors named "Hiraku Watanabe"

8 Publications

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Gray Matter Volume Variability in Young Healthy Adults: Influence of Gender Difference and Brain-Derived Neurotrophic Factor Genotype.

Cereb Cortex 2021 Oct 11. Epub 2021 Oct 11.

Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata-City, Niigata, Niigata, 950-3198, Japan.

Although brain gray matter (GM) plastically changes during short-term training, it is still unclear whether brain structures are stable for short periods (several months). Therefore, this study aimed to re-test the short-term variability of GM volumes and to clarify the effect of factors (gender and BDNF-genotype) expected to contribute to such variability. The subjects comprised 41 young healthy adults. T1-weighted images were acquired twice with an interval of approximately 4 months using a 3 T-MRI scanner. Voxel-based morphometry (VBM) was used to calculate GM volumes in 47 regions. The intraclass correlation coefficient (ICC) and Test-retest variability (%TRV) were used as indices of variability. As a result, the ICCs in 43 regions were excellent (ICC > 0.90) and those in 3 regions were good (ICC > 0.80), whereas the ICC in the thalamus was moderate (ICC = 0.694). Women had a higher %TRV than men in 5 regions, and %TRV of the Val66Val group was higher than that of the Met carrier group in 2 regions. Moreover, the Female-Val66Val group had a higher %TRV than the Male-Met carrier group in 3 regions. These results indicate that although the short-term variability of GM volumes is small, it is affected by within-subject factors.
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http://dx.doi.org/10.1093/cercor/bhab370DOI Listing
October 2021

The usefulness of postmortem computed tomography angiography for subdural hematoma caused by rupture of the cortical artery: A report of two autopsy cases and a literature review.

Leg Med (Tokyo) 2021 Nov 12;53:101941. Epub 2021 Jul 12.

Division of Legal Medicine, Department of Community Preventive Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; Center of Cause of Death Investigation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.

Acute subdural hematoma (SDH) occurs following severe head trauma with brain contusion or rupture of bridging veins. Conversely, SDH caused by rupture of a cortical artery without trauma or with minor trauma is also possible. Although over 180 cases of the latter SDH have been reported, they were predominantly diagnosed only during surgery, and therefore, no adequate histological evaluation has been performed. Therefore, essential etiology of this SDH type has remained unclear. In addition, the scarcity of autopsy cases may be attributed to arterial rupture being missed if the microscopic findings are too minimal to detect during autopsy. Here, we describe two autopsy cases of SDH of cortical artery origin. Extravasation on postmortem computed tomography angiography and arterial leakage on macroscopic observation during autopsy facilitated detection of the ruptured artery and allowed detailed histological evaluation of the ruptured artery and adjacent dura mater. The etiology of arterial rupture is briefly described on the basis of histopathological findings in this study and the available literature.
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http://dx.doi.org/10.1016/j.legalmed.2021.101941DOI Listing
November 2021

Contribution of the brain-derived neurotrophic factor and neurometabolites to the motor performance.

Behav Brain Res 2021 Aug 24;412:113433. Epub 2021 Jun 24.

Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata City, Niigata, Japan; Department of Physical Therapy, Niigata University of Health and Welfare, Niigata City, Niigata, Japan. Electronic address:

Individual motor performance ability is affected by various factors. Although the key factor has not yet completely been elucidated, the brain-derived neurotrophic factor (BDNF) genotype as well as neurometabolites may become contibuting factors depending on the learning stage. We investigated the effects of the Met allele of the BDNF gene and those of the neurometabolites on visuomotor learning. In total, 43 healthy participants performed a visuomotor learning task consisting of 10 blocks using the right index finger (Val66Val, n = 15; Val66Met, n = 15; and Met66Met, n = 13). Glutamate plus glutamine (Glx) concentrations in the primary motor cortex, primary somatosensory cortex (S1), and cerebellum were evaluated using 3-T magnetic resonance spectroscopy in 19 participants who participated in the visuomotor learning task. For the learning stage, the task error (i.e., learning ability) was significantly smaller in the Met66Met group compared with that observed in the remaining groups, irrespective of the learning stage (all p values < 0.003). A significant difference was observed between the Val66Val and Met66Met groups in the learning slope (i.e., learning speed) in the early learning stage (p = 0.048) but not in the late learning stage (all p values> 0.54). Moreover, positive correlations were detected between the learning slope and Glx concentrations in S1 only in the early learning stage (r = 0.579, p = 0.009). The BDNF genotype and Glx concentrations in S1 partially contribute to interindividual variability on learning speed in the early learning stage.
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http://dx.doi.org/10.1016/j.bbr.2021.113433DOI Listing
August 2021

Influence of Brain-Derived Neurotrophic Factor Genotype on Short-Latency Afferent Inhibition and Motor Cortex Metabolites.

Brain Sci 2021 Mar 20;11(3). Epub 2021 Mar 20.

Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan.

The Met allele of the brain-derived neurotrophic factor (BDNF) gene confers reduced cortical BDNF expression and associated neurobehavioral changes. BDNF signaling influences the survival, development, and synaptic function of cortical networks. Here, we compared gamma-aminobutyric acid (GABA)ergic network activity in the human primary motor cortex (M1) between the Met (Val/Met and Met/Met) and non-Met (Val/Val) genotype groups. Short- and long-interval intracortical inhibition, short-latency afferent inhibition (SAI), and long-latency afferent inhibition were measured using transcranial magnetic stimulation (TMS) as indices of GABAergic activity. Furthermore, the considerable inter-individual variability in inhibitory network activity typically measured by TMS may be affected not only by GABA but also by other pathways, including glutamatergic and cholinergic activities; therefore, we used 3-T magnetic resonance spectroscopy (MRS) to measure the dynamics of glutamate plus glutamine (Glx) and choline concentrations in the left M1, left somatosensory cortex, and right cerebellum. All inhibitory TMS conditions produced significantly smaller motor-evoked potentials than single-pulses. SAI was significantly stronger in the Met group than in the Val/Val group. Only the M1 Glx concentration was significantly lower in the Met group, while the BDNF genotype did not affect choline concentration in any region. Further, a positive correlation was observed between SAI and Glx concentrations only in M1. Our findings provide evidence that the BDNF genotype regulates both the inhibitory and excitatory circuits in human M1. In addition, lower Glx concentration in the M1 of Met carriers may alter specific inhibitory network on M1, thereby influencing the cortical signal processing required for neurobehavioral functions.
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http://dx.doi.org/10.3390/brainsci11030395DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8003639PMC
March 2021

Effect of Repetitive Passive Movement Before Motor Skill Training on Corticospinal Excitability and Motor Learning Depend on BDNF Polymorphisms.

Front Hum Neurosci 2021 5;15:621358. Epub 2021 Feb 5.

Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan.

A decrease in cortical excitability tends to be easily followed by an increase induced by external stimuli via a mechanism aimed at restoring it; this phenomenon is called "homeostatic plasticity." In recent years, although intervention methods aimed at promoting motor learning using this phenomenon have been studied, an optimal intervention method has not been established. In the present study, we examined whether subsequent motor learning can be promoted further by a repetitive passive movement, which reduces the excitability of the primary motor cortex (M1) before motor learning tasks. We also examined the relationship between motor learning and the brain-derived neurotrophic factor. Forty healthy subjects (Val/Val genotype, 17 subjects; Met carrier genotype, 23 subjects) participated. Subjects were divided into two groups of 20 individuals each. The first group was assigned to perform the motor learning task after an intervention consisting in the passive adduction-abduction movement of the right index finger at 5 Hz for 10 min (RPM condition), while the second group was assigned to perform the task without the passive movement (control condition). The motor learning task consisted in the visual tracking of the right index finger. The results showed that the corticospinal excitability was transiently reduced after the passive movement in the RPM condition, whereas it was increased to the level detected in the control condition after the motor learning task. Furthermore, the motor learning ability was decreased immediately after the passive movement; however, the motor performance finally improved to the level observed in the control condition. In individuals carrying the Val/Val genotype, higher motor learning was also found to be related to the more remarkable changes in corticospinal excitability caused by the RPM condition. This study revealed that the implementation of a passive movement before a motor learning tasks did not affect M1 excitatory changes and motor learning efficiency; in contrast, in subjects carrying the Val/Val polymorphism, the more significant excitatory changes in the M1 induced by the passive movement and motor learning task led to the improvement of motor learning efficiency. Our results also suggest that homeostatic plasticity occurring in the M1 is involved in this improvement.
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http://dx.doi.org/10.3389/fnhum.2021.621358DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901944PMC
February 2021

The Repetitive Mechanical Tactile Stimulus Intervention Effects Depend on Input Methods.

Front Neurosci 2020 28;14:393. Epub 2020 Apr 28.

Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan.

Elderly and stroke patients often have low spatial two-point discrimination function. The intervention effect of repetitive mechanical tactile stimulation has been shown to improve the spatial two-point discrimination function. The methods of tactile input are classified as either Active Touch or Passive Touch. In Passive Touch, the tactile stimulus is passively applied on the skin without voluntary movement, whereas in Active Touch, it is applied with voluntary movement. Based on the method of tactile input, tactile stimulation activate different cerebral cortex areas. A previous study reported that the tactile stimulation with Active Touch activate posterior parietal cortex, activated during a spatial two-point discrimination task. Therefore, the present study aimed to investigate the effects of two mechanical tactile stimulation intervention methods on two-point discrimination: tactile stimulation with voluntary movement (Active Touch) and without voluntary movement (Passive Touch). We recruited 15 healthy volunteers aged 20-23 years and applied tactile stimuli on their right index finger for 10 min. The mechanical tactile stimulator comprised 24 tiny plastic pins driven by piezoelectric actuators. In the Active Touch intervention, the pin was rubbed by voluntary movement of the right index finger (abduction 0°-10°) after the appearance of 12 pins. The Passive Touch intervention stimulated the index finger with the 12 pins setting at the centre of index finger. Tactile thresholds were measured using a two-point discrimination measurement device. Two-point discrimination threshold showed significant reduction after Active Touch intervention compared with those pre-intervention (Pre). Two-point discrimination threshold were not significantly modulated after Passive Touch intervention; however, significant negative correlation was observed between the intervention effect on two-point discrimination threshold and the performance Pre. This study suggesting that the effects of repetitive mechanical tactile stimulation depend on the method of tactile input. An effective intervention for improving two-point discrimination threshold is the application of Active Touch condition for 10 min.
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http://dx.doi.org/10.3389/fnins.2020.00393DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7198832PMC
April 2020

An autopsy case of peliosis hepatis with X-linked myotubular myopathy.

Leg Med (Tokyo) 2019 May 18;38:77-82. Epub 2019 Apr 18.

Division of Legal Medicine, Department of Community Preventive Medicine, Niigata University Graduate School of Medicine and Dental Sciences, Niigata, Japan; Center of Cause of Death Investigation, Faculty of Medicine, Niigata University, Niigata, Japan. Electronic address:

This report describes the autopsy case of a 4-year-old boy who died from hepatic hemorrhage and rupture caused by peliosis hepatis with X-linked myotubular myopathy. Peliosis hepatis is characterized by multiple blood-filled cavities of various sizes in the liver, which occurs in chronic wasting disease or with the use of specific drugs. X-linked myotubular myopathy is one of the most serious types of congenital myopathies, in which an affected male infant typically presents with severe hypotonia and respiratory distress immediately after birth. Although each disorder is rare, 12 cases of pediatric peliosis hepatis associated with X-linked myotubular myopathy have been reported, including our case. Peliosis hepatis should be considered as a cause of hepatic hemorrhage despite its low incidence, and it requires adequate gross and histological investigation for correct diagnosis.
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http://dx.doi.org/10.1016/j.legalmed.2019.04.005DOI Listing
May 2019

Physical Property Evaluation of ZnO Thin Film Fabricated by Low-Temperature Process for Flexible Transparent TFT.

J Nanosci Nanotechnol 2016 Apr;16(4):3168-75

The usual silicon-based display back planes require fairly high process temperature and thus the development of a low temperature process is needed on flexible plastic substrates. A new type of flexible organic light emitting transistor (OLET) had been proposed and investigated in the previous work. By using ultraviolet/ozone (UV/O3) assisted thermal treatments on wet processed zinc oxide field effect transistor (ZnO-FET), through low-process temperature, ZnO-FETs were fabricated which succeeded to achieve target drain current value and mobility. In this study, physical property evaluation of ZnO was conducted in term of their crystallinity, the increase composition of ZnO formed inside the thin film and the decrease of the carbon impurities originated from aqueous solution of the ZnO itself. The X-ray diffraction (XRD) evaluation showed UV/03 assisted thermal treatment has no obvious effect towards crystallinity of ZnO in the range of low process temperature. Moreover, through X-ray photoelectron spectroscopy (XPS) evaluation and Fourier transform infrared (FT-IR) spectroscopy evaluation, more carbon impurities disappeared from the ZnO thin film and the increase of composition amount of ZnO, when the thin film was subjected to UV/O3 assisted thermal treatment. Therefore, UV/O3 assisted thermal treatment contributed in carbon impurities elimination and accelerate ZnO formation in ZnO thin film, which led to the improvement in the electrical property of ZnO-FET in the low-process temperature.
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http://dx.doi.org/10.1166/jnn.2016.12283DOI Listing
April 2016
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