PLOS ONE: [sortOrder=DATE_NEWEST_FIRST, from=authorLink, sort=Relevance, q=author:"Ryuta Kawashima"]PLOShttps://journals.plos.org/plosone/webmaster@plos.orgaccelerating the publication of peer-reviewed sciencehttps://journals.plos.org/plosone/search/feed/atom?sortOrder=DATE_NEWEST_FIRST&unformattedQuery=author:%22Ryuta%20Kawashima%22&from=authorLink&sort=RelevanceAll PLOS articles are Open Access.https://journals.plos.org/plosone/resource/img/favicon.icohttps://journals.plos.org/plosone/resource/img/favicon.ico2024-03-28T17:02:50ZMagnetoencephalographic evaluation of repaired lip sensation in patients with cleft lipChihiro KitayamaEriya ShimadaHiroki HiharaAkitake KannoNobukazu NakasatoYoshimichi ImaiAkimitsu SatoRyuta KawashimaKaoru IgarashiHiroyasu Kanetaka10.1371/journal.pone.02744052022-09-22T14:00:00Z2022-09-22T14:00:00Z<p>by Chihiro Kitayama, Eriya Shimada, Hiroki Hihara, Akitake Kanno, Nobukazu Nakasato, Yoshimichi Imai, Akimitsu Sato, Ryuta Kawashima, Kaoru Igarashi, Hiroyasu Kanetaka</p>
Background <p>Cleft lip is the most common congenital anomaly worldwide. Nevertheless, lip somatosensory characteristics of patients with cleft lip after cheiloplasty have not yet been determined. The present study used magnetoencephalography to objectively evaluate the lip sensation in patients with unilateral cleft lip to establish a new objective evaluation method.</p> Methods <p>Participants were 15 patients with unilateral cleft lip after cheiloplasty (UCL group), and 30 healthy young subjects (control group). Five points of the upper and lower lips were stimulated electrically to measure somatosensory evoked magnetic fields (SEFs). The sources of the magnetic fields were modeled as single equivalent current dipoles (ECDs). ECDs located on the central sulcus by superimposition on magnetic resonance images were analyzed. Latency and intensity at 50–75 ms (cP60m) observed in the UCL group were compared with those in the control group. Thresholds of tactile stimuli in both groups were obtained using Semmes–Weinstein monofilaments for subjective sensory evaluation.</p> Results <p>No significant difference was found in the intensity of the cP60m or subjective evaluation between the groups. However, the latency of the cP60m was significantly longer in the upper lip of the UCL group than in the control group.</p> Conclusions <p>SEFs showed a difference in lip sensation between the UCL group and the control group, suggesting that longer latency might be caused by the effects of surgical scarring on the neurotransmission pathway. These results suggest SEFs as useful for the objective evaluation of lip sensations. This study might improve future surgical procedures and lip functions of patients with cleft lip.</p>Different contra-sound effects between noise and music stimuli seen in N1m and psychophysical responsesMasayuki ShirakuraTetsuaki KawaseAkitake KannoJun OhtaNobukazu NakasatoRyuta KawashimaYukio Katori10.1371/journal.pone.02616372021-12-20T14:00:00Z2021-12-20T14:00:00Z<p>by Masayuki Shirakura, Tetsuaki Kawase, Akitake Kanno, Jun Ohta, Nobukazu Nakasato, Ryuta Kawashima, Yukio Katori</p>
Auditory-evoked responses can be affected by the sound presented to the contralateral ear. The different contra-sound effects between noise and music stimuli on N1m responses of auditory-evoked fields and those on psychophysical response were examined in 12 and 15 subjects, respectively. In the magnetoencephalographic study, the stimulus to elicit the N1m response was a tone burst of 500 ms duration at a frequency of 250 Hz, presented at a level of 70 dB, and white noise filtered with high-pass filter at 2000 Hz and music stimuli filtered with high-pass filter at 2000 Hz were used as contralateral noise. The contralateral stimuli (noise or music) were presented in 10 dB steps from 80 dB to 30 dB. Subjects were instructed to focus their attention to the left ear and to press the response button each time they heard burst stimuli presented to the left ear. In the psychophysical study, the effects of contralateral sound presentation on the response time for detection of the probe sound of a 250 Hz tone burst presented at a level of 70 dB were examined for the same contra-noise and contra-music used in the magnetoencephalographic study. The amplitude reduction and latency delay of N1m caused by contra-music stimuli were significantly larger than those by contra-noise stimuli in bilateral hemisphere, even for low level of contra-music near the psychophysical threshold. Moreover, this larger suppressive effect induced by contra-music effects was also observed psychophysically; i.e., the change in response time for detection of the probe sound was significantly longer by adding contralateral music stimuli than by adding contra-noise stimuli. Regarding differences in effect between contra-music and contra-noise, differences in the degree of saliency may be responsible for their different abilities to disturb auditory attention to the probe sound, but further investigation is required to confirm this hypothesis.Brain structures and activity during a working memory task associated with internet addiction tendency in young adults: A large sample studySaeid SadeghiHikaru TakeuchiBita ShalaniYasuyuki TakiRui NouchiRyoichi YokoyamaYuka KotozakiSeishu NakagawaAtsushi SekiguchiKunio IizukaSugiko HanawaTsuyoshi ArakiCarlos Makoto MiyauchiKohei SakakiTakayuki NozawaShigeyuki IkedaSusumu YokotaDaniele MagistroYuko SassaRyuta Kawashima10.1371/journal.pone.02592592021-11-15T14:00:00Z2021-11-15T14:00:00Z<p>by Saeid Sadeghi, Hikaru Takeuchi, Bita Shalani, Yasuyuki Taki, Rui Nouchi, Ryoichi Yokoyama, Yuka Kotozaki, Seishu Nakagawa, Atsushi Sekiguchi, Kunio Iizuka, Sugiko Hanawa, Tsuyoshi Araki, Carlos Makoto Miyauchi, Kohei Sakaki, Takayuki Nozawa, Shigeyuki Ikeda, Susumu Yokota, Daniele Magistro, Yuko Sassa, Ryuta Kawashima</p>
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 ± 1.78 years). We found a significant positive correlation between IAT score and gray matter volume (GMV) of right supramarginal gyrus (rSMG) and significant negative correlations with white matter volume (WMV) of right temporal lobe (sub-gyral and superior temporal gyrus), right sublobar area (extra-nuclear and lentiform nucleus), right cerebellar anterior lobe, cerebellar tonsil, right frontal lobe (inferior frontal gyrus and sub-gyral areas), and the pons. Also, IAT was significantly and positively correlated with brain activity in the default-mode network (DMN), medial frontal gyrus, medial part of the superior frontal gyrus, and anterior cingulate cortex during a 2-back working memory (WM) task. Moreover, whole-brain analyses of rGMV showed significant effects of interaction between sex and the IAT scores in the area spreading around the left anterior insula and left lentiform. This interaction was moderated by positive correlation in women. These results indicate that IAT is associated with (a) increased GMV in rSMG, which is involved in phonological processing, (b) decreased WMV in areas of frontal, sublobar, and temporal lobes, which are involved in response inhibition, and (c) reduced task-induced deactivation of the DMN, indicative of altered attentional allocation.rs1360780 of the <i>FKBP5</i> gene modulates the association between maternal acceptance and regional gray matter volume in the thalamus in children and adolescentsIzumi MatsudairaKentaro ObaHikaru TakeuchiAtsushi SekiguchiHiroaki TomitaYasuyuki TakiRyuta Kawashima10.1371/journal.pone.02217682019-08-29T14:00:00Z2019-08-29T14:00:00Z<p>by Izumi Matsudaira, Kentaro Oba, Hikaru Takeuchi, Atsushi Sekiguchi, Hiroaki Tomita, Yasuyuki Taki, Ryuta Kawashima</p>
Investigating the effects of gene–environment interactions (G × E) with regard to brain structure may help to elucidate the putative mechanisms associated with psychiatric risk. rs1360780 (C/T) is a functional single-nucleotide polymorphism (SNP) in the gene encoding FK506–binding protein 5 (FKBP5), which is involved in the regulation of the hypothalamic–pituitary–adrenal (HPA) axis stress responses. The minor (T) allele of <i>FKBP5</i> is considered a risk allele for stress-related disorders, due to the overproduction of FKBP5, which results in impaired communication of stress signals with the HPA axis. Previous studies have reported that interactions between childhood maltreatment and the rs1360780 genotype affect structures in subcortical areas of the brain. However, it is unclear how this SNP modulates the association between non-adverse environments and brain structure. In this study, we examined the interactive effect of the rs1360780 genotype and maternal acceptance on the regional gray matter volume (rGMV) in 202 Japanese children. Maternal acceptance was assessed using a Japanese psychological questionnaire for mothers. Whole-brain multiple regression analysis using voxel-based morphometry showed a significant positive association between maternal acceptance and rGMV in the left thalamus of T-allele carriers, while a significant negative association was found in C/C homozygotes. Post-hoc analysis revealed that at or below the 70th percentiles of maternal acceptance, the T-allele carriers had a reduced thalamic rGMV compared with that of C/C homozygotes. Thus, our investigation indicated that the effect of the maternal acceptance level on brain development was different, depending on the rs1360780 genotype. Importantly, we found that the differences in brain structure between the T-allele carriers and C/C homozygotes at low to moderate levels of maternal acceptance, which is not equivalent to maltreatment. The present study contributes to the G × E research by highlighting the necessity to investigate the role of non-adverse environmental factors.Does incidental pride increase competency evaluation of others who appear careless? Discrete positive emotions and impression formationToshiki SaitoKosuke MotokiRui NouchiRyuta KawashimaMotoaki Sugiura10.1371/journal.pone.02208832019-08-08T14:00:00Z2019-08-08T14:00:00Z<p>by Toshiki Saito, Kosuke Motoki, Rui Nouchi, Ryuta Kawashima, Motoaki Sugiura</p>
Emotion plays important and diverse roles across various social relations. Although the social functions of emotion have attracted increased attention, the effects of positive emotions such as pride on impression formation remain poorly understood. Drawing on social projection theory, this study examined how incidental experiences of pride influenced the impressions of those who made a blunder, along with two other characteristics: the person’s warmth and competence. Participants were designated randomly to receive inductions of pride, awe, or a neutral emotion. Subsequently, they were asked to indicate their own impression of a person who had made a blunder and to rate their overall sense of that individual’s warmth and competence. A laboratory experiment recruiting university students (Study 1, N = 79) demonstrated that pride, a positive emotion elicited by a self-relevant achievement, led to higher competency evaluations of others. However, a pre-registered online experiment in middle-aged adults (Study 2, N = 108) failed to replicate the effects of pride on competency evaluations of others. Furthermore, another pre-registered online experiment in younger adults (Study 3, N = 290) did not show successful manipulation of incidental emotions. These results suggest that strictly controlled experimental settings that induce robust incidental emotions might be better for demonstrating a strong pride effect on the evaluation of others.Evaluating age-related change in lip somatosensation using somatosensory evoked magnetic fieldsHiroki HiharaHiroyasu KanetakaAkitake KannoSatoko KoedaNobukazu NakasatoRyuta KawashimaKeiichi Sasaki10.1371/journal.pone.01793232017-06-15T14:00:00Z2017-06-15T14:00:00Z<p>by Hiroki Hihara, Hiroyasu Kanetaka, Akitake Kanno, Satoko Koeda, Nobukazu Nakasato, Ryuta Kawashima, Keiichi Sasaki</p>
Somatosensory evoked fields (SEFs) to electrical stimulation on the right and left sides of the lower lip were measured using magnetoencephalography and compared in the bilateral hemispheres of 31 healthy normal young and 29 healthy normal elderly subjects to evaluate age-related change in lip somatosensation. The initial peak of the response around 13 ms, designated as N13m, and the second peak of the response, designated as P21m, were investigated. The N13m response, which was detected in 22 of 62 hemispheres in young adults and 37 of 58 hemispheres in elderly adults, showed significantly prolonged latency and increased equivalent current dipole (ECD) moment in the elderly adults. The P21m response, which was detected in 56 of 62 hemispheres in young adults and in 52 of 58 hemispheres in elderly adults, showed longer peak latency in the elderly adults. No significant difference was found in the ECD moment for P21m, which suggests that aging affected the SEFs of the lip somatosensation, but the effects of aging on N13m and P21m differed. Prolonged latency and increased ECD moment of N13m might result from decreased peripheral conduction and increased cortical excitation system associated with aging. Therefore, the initial response component might be an objective parameter for investigating change in lip function with age.Effects of Visual Speech on Early Auditory Evoked Fields - From the Viewpoint of Individual VarianceIzumi YahataTetsuaki KawaseAkitake KannoHiroshi HidakaShuichi SakamotoNobukazu NakasatoRyuta KawashimaYukio Katori10.1371/journal.pone.01701662017-01-31T14:00:00Z2017-01-31T14:00:00Z<p>by Izumi Yahata, Tetsuaki Kawase, Akitake Kanno, Hiroshi Hidaka, Shuichi Sakamoto, Nobukazu Nakasato, Ryuta Kawashima, Yukio Katori</p>
The effects of visual speech (the moving image of the speaker’s face uttering speech sound) on early auditory evoked fields (AEFs) were examined using a helmet-shaped magnetoencephalography system in 12 healthy volunteers (9 males, mean age 35.5 years). AEFs (N100m) in response to the monosyllabic sound /be/ were recorded and analyzed under three different visual stimulus conditions, the moving image of the same speaker’s face uttering /be/ (congruent visual stimuli) or uttering /ge/ (incongruent visual stimuli), and visual noise (still image processed from speaker’s face using a strong Gaussian filter: control condition). On average, latency of N100m was significantly shortened in the bilateral hemispheres for both congruent and incongruent auditory/visual (A/V) stimuli, compared to the control A/V condition. However, the degree of N100m shortening was not significantly different between the congruent and incongruent A/V conditions, despite the significant differences in psychophysical responses between these two A/V conditions. Moreover, analysis of the magnitudes of these visual effects on AEFs in individuals showed that the lip-reading effects on AEFs tended to be well correlated between the two different audio-visual conditions (congruent vs. incongruent visual stimuli) in the bilateral hemispheres but were not significantly correlated between right and left hemisphere. On the other hand, no significant correlation was observed between the magnitudes of visual speech effects and psychophysical responses. These results may indicate that the auditory-visual interaction observed on the N100m is a fundamental process which does not depend on the congruency of the visual information.Impact of Audio-Visual Asynchrony on Lip-Reading Effects -Neuromagnetic and Psychophysical Study-Tetsuaki KawaseIzumi YahataAkitake KannoShuichi SakamotoYoshitaka TakanashiShiho TakataNobukazu NakasatoRyuta KawashimaYukio Katori10.1371/journal.pone.01687402016-12-28T14:00:00Z2016-12-28T14:00:00Z<p>by Tetsuaki Kawase, Izumi Yahata, Akitake Kanno, Shuichi Sakamoto, Yoshitaka Takanashi, Shiho Takata, Nobukazu Nakasato, Ryuta Kawashima, Yukio Katori</p>
The effects of asynchrony between audio and visual (A/V) stimuli on the N100m responses of magnetoencephalography in the left hemisphere were compared with those on the psychophysical responses in 11 participants. The latency and amplitude of N100m were significantly shortened and reduced in the left hemisphere by the presentation of visual speech as long as the temporal asynchrony between A/V stimuli was within 100 ms, but were not significantly affected with audio lags of -500 and +500 ms. However, some small effects were still preserved on average with audio lags of 500 ms, suggesting similar asymmetry of the temporal window to that observed in psychophysical measurements, which tended to be more robust (wider) for audio lags; i.e., the pattern of visual-speech effects as a function of A/V lag observed in the N100m in the left hemisphere grossly resembled that in psychophysical measurements on average, although the individual responses were somewhat varied. The present results suggest that the basic configuration of the temporal window of visual effects on auditory-speech perception could be observed from the early auditory processing stage.Regional Volume Decreases in the Brain of <i>Pax6</i> Heterozygous Mutant Rats: MRI Deformation-Based MorphometryKotaro HiraokaAkira SumiyoshiHiroi NonakaTakako KikkawaRyuta KawashimaNoriko Osumi10.1371/journal.pone.01581532016-06-29T14:00:00Z2016-06-29T14:00:00Z<p>by Kotaro Hiraoka, Akira Sumiyoshi, Hiroi Nonaka, Takako Kikkawa, Ryuta Kawashima, Noriko Osumi</p>
Pax6 is a transcription factor that pleiotropically regulates various developmental processes in the central nervous system. In a previous study, we revealed that <i>Pax6</i> heterozygous mutant (<i>rSey</i><sup>2</sup>/+) adult rats exhibit abnormalities in social interaction. However, the brain malformations underlying the behavioral abnormality are unknown. To elucidate the brain malformations in <i>rSey</i><sup>2</sup>/+ rats, we morphometrically analyzed brains of <i>rSey</i><sup>2</sup>/+ and wild type rats using small-animal magnetic resonance imaging (MRI). Sixty 10-week-old rats underwent brain MRI (29 <i>rSey</i><sup>2</sup>/+ rats and 31 wild type rats). SPM8 software was used for image preprocessing and statistical image analysis. Normalized maps of the Jacobian determinant, a parameter for the expansion and/or contraction of brain regions, were obtained for each rat. <i>rSey</i><sup>2</sup>/+ rats showed significant volume decreases in various brain regions including the neocortex, corpus callosum, olfactory structures, hippocampal formation, diencephalon, and midbrain compared to wild type rats. Among brain regions, the anterior commissure showed significant interaction between genotype and sex, indicating the effect of genotype difference on the anterior commissure volume was more robust in females than in males. The <i>rSey</i><sup>2</sup>/+ rats exhibited decreased volume in various gray and white matter regions of the brain, which may contribute to manifestation of abnormal social behaviors.Parental Praise Correlates with Posterior Insular Cortex Gray Matter Volume in Children and AdolescentsIzumi MatsudairaSusumu YokotaTeruo HashimotoHikaru TakeuchiKohei AsanoMichiko AsanoYuko SassaYasuyuki TakiRyuta Kawashima10.1371/journal.pone.01542202016-04-21T14:00:00Z2016-04-21T14:00:00Z<p>by Izumi Matsudaira, Susumu Yokota, Teruo Hashimoto, Hikaru Takeuchi, Kohei Asano, Michiko Asano, Yuko Sassa, Yasuyuki Taki, Ryuta Kawashima</p>
A positive parenting style affects psychological and cognitive development in children. Neuroimaging studies revealed that a positive parenting style influenced brain structure in children. Parental praise is a concrete behavior observed in positive parenting. Although previous psychological studies revealed a positive effect of parental praise on children, little is known about the relationship between parental praise and brain structure in children. Thus, the purpose of the present study was to determine whether there was a correlation between the parental attitude towards praising their child and gray matter volume in the children (116 boys and 109 girls; mean age, 10.6 years old). We examined the correlation between regional gray matter volume and parental praise using voxel-based morphometry (VBM) following magnetic resonance imaging (MRI). In addition, to confirm the positive effects of parental praise, we analyzed the correlation between the frequency of parental praise and personality traits in children. We showed that the parental attitude towards praising their child was significantly and positively correlated with the gray matter volume of the left posterior insular cortex in children. Moreover, we found a significant positive correlation between parental attitude towards praising their child and the personality traits of conscientiousness and openness to experience in the children. Prior studies said that gray matter volume in the posterior insula was correlated with empathy, and the functional connectivity between this area and the amygdala was associated with emotional regulation. Furthermore, the posterior insula relates to auditory function, and therefore, was likely involved in the processing of parental praise. Considering the possibility of experience-dependent plasticity, frequent parental praise would lead to increased posterior insular gray matter volume in children. Our study is the first to elucidate the relationship between a specific positive parenting behavior and brain structure in children.Postoperative Structural Brain Changes and Cognitive Dysfunction in Patients with Breast CancerChiho SatoAtsushi SekiguchiMasaaki KawaiYuka KotozakiRui NouchiHiroshi TadaHikaru TakeuchiTakanori IshidaYasuyuki TakiRyuta KawashimaNoriaki Ohuchi10.1371/journal.pone.01406552015-11-04T14:00:00Z2015-11-04T14:00:00Z<p>by Chiho Sato, Atsushi Sekiguchi, Masaaki Kawai, Yuka Kotozaki, Rui Nouchi, Hiroshi Tada, Hikaru Takeuchi, Takanori Ishida, Yasuyuki Taki, Ryuta Kawashima, Noriaki Ohuchi</p>
Objective <p>The primary purpose of this study was to clarify the influence of the early response to surgery on brain structure and cognitive function in patients with breast cancer. It was hypothesized that the structure of the thalamus would change during the early response after surgery due to the effects of anesthesia and would represent one aspect of an intermediate phenotype of postoperative cognitive dysfunction (POCD).</p> Methods <p>We examined 32 postmenopausal females with breast cancer and 20 age-matched controls. We assessed their cognitive function (attention, memory, and executive function), and performed brain structural MRI 1.5 ± 0.5 days before and 5.6 ± 1.2 days after surgery.</p> Results <p>We found a significant interaction between regional grey matter volume (rGMV) in the thalamus (<i>P</i> < 0.05, familywise error (FWE), small volume correction (SVC)) and one attention domain subtest (<i>P</i> = 0.001, Bonferroni correction) after surgery in the patient group compared with the control group. Furthermore, the changes in attention were significantly associated with sevoflurane anesthetic dose (<i>r</i><sup>2</sup> = 0.247, β = ‒0.471, <i>P</i> = 0.032) and marginally associated with rGMV changes in the thalamus (<i>P</i> = 0.07, FWE, SVC) in the Pt group.</p> Conclusion <p>Our findings suggest that alterations in brain structure, particularly in the thalamus, may occur shortly after surgery and may be associated with attentional dysfunction. This early postoperative response to anesthesia may represent an intermediate phenotype of POCD. It was assumed that patients experiencing other risk factors of POCD, such as the severity of surgery, the occurrence of complications, and pre-existing cognitive impairments, would develop clinical POCD with broad and multiple types of cognitive dysfunction.</p>The Relationship between Processing Speed and Regional White Matter Volume in Healthy Young PeopleDaniele MagistroHikaru TakeuchiKeyvan Kashkouli NejadYasuyuki TakiAtsushi SekiguchiRui NouchiYuka KotozakiSeishu NakagawaCarlos Makoto MiyauchiKunio IizukaRyoichi YokoyamaTakamitsu ShinadaYuki YamamotoSugiko HanawaTsuyoshi ArakiHiroshi HashizumeYuko SassaRyuta Kawashima10.1371/journal.pone.01363862015-09-23T14:00:00Z2015-09-23T14:00:00Z<p>by Daniele Magistro, Hikaru Takeuchi, Keyvan Kashkouli Nejad, Yasuyuki Taki, Atsushi Sekiguchi, Rui Nouchi, Yuka Kotozaki, Seishu Nakagawa, Carlos Makoto Miyauchi, Kunio Iizuka, Ryoichi Yokoyama, Takamitsu Shinada, Yuki Yamamoto, Sugiko Hanawa, Tsuyoshi Araki, Hiroshi Hashizume, Yuko Sassa, Ryuta Kawashima</p>
Processing speed is considered a key cognitive resource and it has a crucial role in all types of cognitive performance. Some researchers have hypothesised the importance of white matter integrity in the brain for processing speed; however, the relationship at the whole-brain level between white matter volume (WMV) and processing speed relevant to the modality or problem used in the task has never been clearly evaluated in healthy people. In this study, we used various tests of processing speed and Voxel-Based Morphometry (VBM) analyses, it is involves a voxel-wise comparison of the local volume of gray and white, to assess the relationship between processing speed and regional WMV (rWMV). We examined the association between processing speed and WMV in 887 healthy young adults (504 men and 383 women; mean age, 20.7 years, SD, 1.85). We performed three different multiple regression analyses: we evaluated rWMV associated with individual differences in the simple processing speed task, word–colour and colour–word tasks (processing speed tasks with words) and the simple arithmetic task, after adjusting for age and sex. The results showed a positive relationship at the whole-brain level between rWMV and processing speed performance. In contrast, the processing speed performance did not correlate with rWMV in any of the regions examined. Our results support the idea that WMV is associated globally with processing speed performance regardless of the type of processing speed task.Temporal and Motor Representation of Rhythm in Fronto-Parietal Cortical Areas: An fMRI StudyNaho KonoikeYuka KotozakiHyeonjeong JeongAtsuko MiyazakiKohei SakakiTakamitsu ShinadaMotoaki SugiuraRyuta KawashimaKatsuki Nakamura10.1371/journal.pone.01301202015-06-15T14:00:00Z2015-06-15T14:00:00Z<p>by Naho Konoike, Yuka Kotozaki, Hyeonjeong Jeong, Atsuko Miyazaki, Kohei Sakaki, Takamitsu Shinada, Motoaki Sugiura, Ryuta Kawashima, Katsuki Nakamura</p>
When sounds occur with temporally structured patterns, we can feel a rhythm. To memorize a rhythm, perception of its temporal patterns and organization of them into a hierarchically structured sequence are necessary. On the other hand, rhythm perception can often cause unintentional body movements. Thus, we hypothesized that rhythm information can be manifested in two different ways; temporal and motor representations. The motor representation depends on effectors, such as the finger or foot, whereas the temporal representation is effector-independent. We tested our hypothesis with a working memory paradigm to elucidate neuronal correlates of temporal or motor representation of rhythm and to reveal the neural networks associated with these representations. We measured brain activity by fMRI while participants memorized rhythms and reproduced them by tapping with the right finger, left finger, or foot, or by articulation. The right inferior frontal gyrus and the inferior parietal lobule exhibited significant effector-independent activations during encoding and retrieval of rhythm information, whereas the left inferior parietal lobule and supplementary motor area (SMA) showed effector-dependent activations during retrieval. These results suggest that temporal sequences of rhythm are probably represented in the right fronto-parietal network, whereas motor sequences of rhythm can be represented in the SMA-parietal network.Regional Gray Matter Density Associated with Cognitive Reflectivity–Impulsivity: Evidence from Voxel-Based MorphometryRyoichi YokoyamaTakayuki NozawaHikaru TakeuchiYasuyuki TakiAtsushi SekiguchiRui NouchiYuka KotozakiSeishu NakagawaCarlos Makoto MiyauchiKunio IizukaTakamitsu ShinadaYuki YamamotoSugiko HanawaTsuyoshi ArakiHiroshi HashizumeKeiko KunitokiMayu HaniharaYuko SassaRyuta Kawashima10.1371/journal.pone.01226662015-03-24T14:00:00Z2015-03-24T14:00:00Z<p>by Ryoichi Yokoyama, Takayuki Nozawa, Hikaru Takeuchi, Yasuyuki Taki, Atsushi Sekiguchi, Rui Nouchi, Yuka Kotozaki, Seishu Nakagawa, Carlos Makoto Miyauchi, Kunio Iizuka, Takamitsu Shinada, Yuki Yamamoto, Sugiko Hanawa, Tsuyoshi Araki, Hiroshi Hashizume, Keiko Kunitoki, Mayu Hanihara, Yuko Sassa, Ryuta Kawashima</p>
When faced with a problem or choice, humans can use two different strategies: “cognitive reflectivity,” which involves slow responses and fewer mistakes, or “cognitive impulsivity,” which comprises of quick responses and more mistakes. Different individuals use these two strategies differently. To our knowledge, no study has directly investigated the brain regions involved in reflectivity–impulsivity; therefore, this study focused on associations between these cognitive strategies and the gray matter structure of several brain regions. In order to accomplish this, we enrolled 776 healthy, right-handed individuals (432 men and 344 women; 20.7 ± 1.8 years) and used voxel-based morphometry with administration of a cognitive reflectivity–impulsivity questionnaire. We found that high cognitive reflectivity was associated with greater regional gray matter density in the ventral medial prefrontal cortex. Our finding suggests that this area plays an important role in defining an individual’s trait associated with reflectivity and impulsivity.Effects of Contralateral Noise on the 20-Hz Auditory Steady State Response - Magnetoencephalography StudyHajime UsubuchiTetsuaki KawaseAkitake KannoIzumi YahataHiromitsu MiyazakiNobukazu NakasatoRyuta KawashimaYukio Katori10.1371/journal.pone.00994572014-06-10T14:00:00Z2014-06-10T14:00:00Z<p>by Hajime Usubuchi, Tetsuaki Kawase, Akitake Kanno, Izumi Yahata, Hiromitsu Miyazaki, Nobukazu Nakasato, Ryuta Kawashima, Yukio Katori</p>
The auditory steady state response (ASSR) is an oscillatory brain response, which is phase locked to the rhythm of an auditory stimulus. ASSRs have been recorded in response to a wide frequency range of modulation and/or repetition, but the physiological features of the ASSRs are somewhat different depending on the modulation frequency. Recently, the 20-Hz ASSR has been emphasized in clinical examinations, especially in the area of psychiatry. However, little is known about the physiological properties of the 20-Hz ASSR, compared to those of the 40-Hz and 80-Hz ASSRs. The effects of contralateral noise on the ASSR are known to depend on the modulation frequency to evoke ASSR. However, the effects of contralateral noise on the 20-Hz ASSR are not known. Here we assessed the effects of contralateral white noise at a level of 70 dB SPL on the 20-Hz and 40-Hz ASSRs using a helmet-shaped magnetoencephalography system in 9 healthy volunteers (8 males and 1 female, mean age 31.2 years). The ASSRs were elicited by monaural 1000-Hz 5-s tone bursts amplitude-modulated at 20 and 39 Hz and presented at 80 dB SPL. Contralateral noise caused significant suppression of both the 20-Hz and 40-Hz ASSRs, although suppression was significantly smaller for the 20-Hz ASSRs than the 40-Hz ASSRs. Moreover, the greatest suppression of both 20-Hz and 40-Hz ASSRs occurred in the right hemisphere when stimuli were presented to the right ear with contralateral noise. The present study newly showed that 20-Hz ASSRs are suppressed by contralateral noise, which may be important both for characterization of the 20-Hz ASSR and for interpretation in clinical situations. Physicians must be aware that the 20-Hz ASSR is significantly suppressed by sound (e.g. masking noise or binaural stimulation) applied to the contralateral ear.