Details of a Researcher - SUGAWARA Kazuhiro

Papers - SUGAWARA Kazuhiro

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Effects of complex movement on the excitability of the ipsilateral primary motor cortex and spinal motoneurons contralateral to the movement: A comparison of ball rotation and grasping tasks with equivalent muscle activity

Kosuge R., Sukegawa T., Akaiwa M., Shibata E., Kurokawa R., Sugawara Y., Kudoh S., Matsuda Y., Saito H., Sasaki T., Sugawara K.

Brain Sciences 15 ( 2 ) 2025.02 [Refereed]

Authorship： Last author , Corresponding author

DOI

Enhancement of beta rebound elicited by proprioceptive stimulation in the sensorimotor cortex by transcranial alternating current stimulation matched to the dominant beta frequency

Akaiwa M., Kurokawa R., Matsuda Y., Sugawara Y., Kosuge R., Saito H., Shibata E., Sasaki T., Sugawara K.

Neuroscience Research ( In press ) 2025 [Refereed]

Authorship： Last author

Effects of Go/NoGo stimulus ratio on reaction time, pre-stimulus preparatory activity, and post-stimulus cognitive processing

Matsuda Y., Akaiwa M., Saito H., Kudoh S., Sugawara Y., Kurokawa R., Kosuge R., Shibata E., Sasaki T., Sugawara K.

Experimental Brain Research (In press) 2025 [Refereed]

Authorship： Last author , Corresponding author

Differing effectiveness of transcranial random noise stimulation and transcranial direct current stimulation for enhancing working memory in healthy individuals: a randomized controlled trial

Tokikuni Y, Watanabe A, Nakazono H, Miura H, Saito R, Miaowen D, Fuyama K, Takahashi K, Okada K, Sugawara K, Tohyama H, Yoshida S, Fong K, Sawamura D

Journal of NeuroEngineering and Rehabilitation ( Springer Science and Business Media LLC ) 21 ( 1 ) 2024.10

Abstract Background Transcranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal cortex (DLPFC) is a promising technique for enhancing working memory (WM) performance in healthy and psychiatric populations. However, limited information is available about the effectiveness of transcranial random noise stimulation (tRNS) applied to the left DLPFC on WM. This study investigated the effectiveness of tRNS on WM compared with that of tDCS, which has established functional evidence. Methods This randomized, double-blind, sham-controlled trial enrolled 120 healthy right-handed adults who were randomly allocated to four stimulation groups: tRNS + direct current (DC) offset, tRNS, tDCS, or sham. Each stimulus was placed over the left DLPFC and had a current intensity of 2 mA applied for 20 min during the dual n-back task. The dual n-back task was repeated thrice: pre-stimulation, during stimulation, and post-stimulation. The d-prime scores, and response times were calculated as the main outcome measures. A linear mixed model was created to identify the main effects and interactions between the groups and times, with the group and time as fixed effects, and baseline performance and the subject as a covariate and random effect, respectively. The relationships between the benefit of each stimulus and baseline WM performance were also examined. Results For the d-prime score during stimulation, the tRNS group significantly performed better than the sham group at online assessment (β = 0.310, p = 0.001). In the relationships between the benefit of each stimulus and baseline WM performance, the tRNS group had significantly larger negative line slopes than the sham group for the d-prime score (β = −0.233, p = 0.038). Conclusions tRNS applied to the left DLPFC significantly improved WM performance and generated greater benefits for healthy individuals with lower WM performance. These findings highlight the potential utility of tRNS for enhancing WM performance in individuals with lower WM performance and contribute evidence for clinical application to patients with cognitive decline. Trial Registration This study was registered in the University Hospital Medical Information Network Clinical Trial Registry in Japan (UMIN000047365) on April 1, 2022; https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000054021.

DOI

Gait Exercise Assist Robot（GEAR）Using Visual and Auditory Feedback Improves Gait in a Hemiplegic Patient with Severe Sensory Impairment：A Case Report

Oikawa Y, Tanaka D, Sakajiri K, Furuta R, Sugawara K

The Japanese Journal of Rehabilitation Medicine ( Japanese Association of Rehabilitation Medicine ) 61 655 - 661 2024.07 [Refereed]

Authorship： Last author , Corresponding author

DOI

Effects of reduced physical activity due to post stroke apathy on time taken to achieve independent walking in a hospital ward -Comparison of two cases with apathy and non apathy

小菅凜, 工藤哲史, 赤岩眞悠, 佐々木健史, 古田亮一, 菅原和広

総合リハビリテーション 52 ( 3 ) 2024.03 [Refereed]

Authorship： Last author , Corresponding author

Event-related brain potentials N140 and P300 during somatosensory Go/NoGo tasks are modulated by movement preparation

Matsuda Y, Sugawara Y, Akaiwa M, Saito H, Shibata E, Sasaki T, Sugawara K

Brain Sciences 14 ( 1 ) 38 2024.01 [Refereed]

Authorship： Last author , Corresponding author

Does 20-Hz Transcranial Alternating Current Stimulation Over Human Primary Motor Cortex Modulate Beta Rebound Following Voluntary Movement?

Akaiwa M, Matsuda Y, Kurokawa R, Sugawara Y, Kosuge R, Saito H, Shibata E, Sasaki T, Sugawara K, Kozuka N

Brain Sciences 14 ( 1 ) 74 2024.01 [Refereed]

Movement of the Stimulated Finger in a Go/NoGo Task Enhances Attention Directed to that Finger as Evidenced by P300 Amplitude Modulation

Sugawara K, Akaiwa M, Matsuda Y, Shibata E, Saito H, Sasaki T

Frontiers in Human Neuroscience ( 17 ) 2023.12 [Refereed]

Authorship： Lead author , Corresponding author

Case Report: Self-restraint in a Patient with Alien Hand Syndrome Following Cerebral Infarction Involving the Anterior Cerebral Artery Territory

Sugawara K, Takeuchi T, Harada K, Taki M, Fujimura I, Kogami Y, Furuta R

Frontiers in Neurology Jul 14:14:1203450 2023.07 [Refereed]

Authorship： Lead author , Corresponding author

DOI

Effects of repetitive practice of motor tasks on somatosensory gating.

Mayu Akaiwa, Yuya Matsuda, Hidekazu Saito, Eriko Shibata, Takeshi Sasaki, Kazuhiro Sugawara

Frontiers in human neuroscience 17 ( 17 ) 1131986 - 1131986 2023.03 [Refereed] [International journal]

Authorship： Last author , Corresponding author

INTRODUCTION: During voluntary muscle contraction, the amplitude of the somatosensory evoked potential (SEP) is reduced by inhibiting sensory information from a peripheral nerve supplying the contracted muscle. This phenomenon is called "gating." We reported that participants with good motor skills indicated strong suppression of somatosensory information. The present study investigated the effects of motor performance improvement following repetitive practice on the SEP amplitude. METHODS: The ball rotation task (BR task) was practiced by 15 healthy participants repetitively. SEPs were recorded before (pre) and after (post) repetitive practice. RESULTS: The BR task performance was significantly improved and the required muscle activation to perform the task was significantly reduced after the repetitive practice. The degree of gating was not significant between pre and post- for the SEP amplitude. A significant correlation was found between changes in SEP amplitude from pre to post and performance improvement. DISCUSSION: After repetitive practice, the degree of gating did not change, but the performance of the BR task improved, and the muscle activity required for the BR task decreased. These results suggest that repetitive practice does not change the degree of gating but changes the mechanism of gating. Furthermore, they indicate that suppression of the somatosensory area may play a role in improving task performance.

DOI PubMed

Transcranial direct current stimulation to the left dorsolateral prefrontal cortex enhances early dexterity skills with the left non-dominant hand; A randomized controlled trial

Watanabe A, Sawamura D, Nakazono H, Tokikuni Y, Miura H, Sugawara K, Furuya K, Tohyama H, Yoshida S, Sakai S

Journal of Translational Medicine ( Springer Science and Business Media LLC ) 21 ( 143 ) 2023.02 [Refereed]

Abstract Background The left dorsolateral prefrontal cortex (DLPFC) is involved in early-phase manual dexterity skill acquisition when cognitive control processes, such as integration and complexity demands, are required. However, the effectiveness of left DLPFC transcranial direct current stimulation (tDCS) on early-phase motor learning and whether its effectiveness depends on the cognitive demand of the target task are unclear. This study aimed to investigate whether tDCS over the left DLPFC improves non-dominant hand dexterity performance and determine if its efficacy depends on the cognitive demand of the target task. Methods In this randomized, double-blind, sham-controlled trial, 70 healthy, right-handed, young adult participants were recruited. They were randomly allocated to the active tDCS (2 mA for 20 min) or sham groups and repeatedly performed the Purdue Pegboard Test (PPT) left-handed peg task and left-handed assembly task three times: pre-tDCS, during tDCS, and post tDCS. Results The final sample comprised 66 healthy young adults (mean age, 22.73 ± 1.57 years). There were significant interactions between group and time in both PPT tasks, indicating significantly higher performance of those in the active tDCS group than those in the sham group post tDCS (p < 0.001). Moreover, a greater benefit was observed in the left-handed assembly task performance than in the peg task performance (p < 0.001). No significant correlation between baseline performance and benefits from tDCS was observed in either task. Conclusions These results demonstrated that prefrontal tDCS significantly improved early-phase manual dexterity skill acquisition, and its benefits were greater for the task with high cognitive demands. These findings contribute to a deeper understanding of the underlying neurophysiological mechanisms of the left DLPFC in the modulation of early-phase dexterity skill acquisition. Trial registration: This study was registered in the University Hospital Medical Information Network Clinical Trial Registry in Japan (UMIN000046868), Registered February 8, 2022 https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000053467

DOI

The relationships between motor behavior and sensory gating in the ball rotation task

Akaiwa M, Matsuda Y, Soma Y, Shibata E, Saito H, Sasaki T, Sugawara K

Experimental Brain Research 240 ( 10 ) 2659 - 2666 2022.10 [Refereed] [International journal]

Authorship： Last author , Corresponding author

During voluntary muscle contraction, sensory information induced by electrostimulation of the nerves supplying the contracting muscle is inhibited and the amplitude of the corresponding somatosensory evoked potential (SEP) decreases. This phenomenon is called "gating." The reduction of the SEP amplitude is reportedly significantly larger when task performance is high. However, the relationship between dexterous movement skills and gating remains unclear. In this study, we investigated through a ball rotation (BR) task how dexterous movement skills affect the SEP amplitudes. Thirty healthy subjects performed the BR task comprising the rotation of two wooden balls as quickly as possible. We estimated the median number of ball rotations for each participant and classified the participants into two (fast and slow) groups based on the results. Moreover, we recorded SEPs, while the subjects performed BR tasks or rested. SEP amplitude reduction (P45) was significantly larger in the fast than in the slow group. We also observed that the P45 amplitude during the BR task was attenuated even more so in the case of the participants with better dexterous movement skills. Our results suggest that the participants with better dexterous movement skills might display stronger somatosensory information suppression because of increasing the motor cortex activity and the afferent input during the BR task.

DOI PubMed

The Impact of Visual Cross-modal Conflict with Semantic and Non-semantic Distractors on Working Memory Task: A Functional Near-infrared Spectroscopy Study

Sawamura D, Tanabe Y, Sakuraba S, Cui J, Miura H, Saito R, Sugi M, Watanabe A, Tokikuni Y, Sugawara K, Miyazaki M, Miyamoto R, Sakai S

Medicine 101 ( 36 ) e30330 2022.09 [Refereed]

The Effect of Pedaling at Different Cadence on Attentional Resources

Akaiwa M, Iwata K, Saito H, Shibata E, Sasaki T, Sugawara K.

Frontiers in Human Neuroscience ( Frontiers Media SA ) 16 819232 - 819232 2022.02 [Refereed] [International journal]

Authorship： Last author , Corresponding author

We investigated the relationship between attentional resources and pedaling cadence using electroencephalography (EEG) to measure P300 amplitudes and latencies. Twenty-five healthy volunteers performed the oddball task while pedaling on a stationary bike or relaxing (i.e., no pedaling). We set them four conditions, namely, (1) performing only the oddball task (i.e., control), (2) performing the oddball task while pedaling at optimal cadence (i.e., optimal), (3) performing the oddball task while pedaling faster than optimal cadence (i.e., fast), and (4) performing the oddball task while pedaling slower than optimal cadence (i.e., slow). P300 amplitudes at Cz and Pz electrodes under optimal, fast, and slow conditions were significantly lower than those under control conditions. P300 amplitudes at Pz under fast and slow conditions were significantly lower than those under the optimal condition. No significant changes in P300 latency at any electrode were observed under any condition. Our findings revealed that pedaling at non-optimal cadence results in less attention being paid to external stimuli compared with pedaling at optimal cadence.

DOI PubMed

電流源推定に使用するMEGセンサーの選択範囲による影響に関する検討

齊藤秀和, 菅原和広, 臼井桂子, 篠崎淳, 石黒雅敬, 白石秀明, 松橋眞生, 長峯隆

日本生体磁気学会誌 ( 日本生体磁気学会 ) 35 ( 1 ) 94 - 95 2022

生体磁気計測関係のアーチファクト MEG計測において歯科矯正器具によるArtifactを認めた一例

齊藤秀和, 菅原和広, 臼井桂子, 篠崎淳, 石黒雅敬, 白石秀明, 松橋眞生, 長峯隆

日本生体磁気学会誌 ( 日本生体磁気学会 ) 35 ( 1 ) 48 - 49 2022

ボールローテーション課題による新たな手指巧緻運動の機能評価に関する検討

齊藤秀和, 菅原和広, 太田久晶

作業療法の実践と科学 ( (公社)北海道作業療法士会 ) 3 ( 1 ) 1 - 8 2021.02 [Refereed]

Altered somatosensory evoked potentials associated with improved reaction time in a simple sensorimotor response task following repetitive practice

Akaiwa M, Iwata K, Saito H, Sasaki T, Sugawara K

Brain and Behavior 2020.06 [Refereed]

Authorship： Last author , Corresponding author

Corticospinal excitability related to reciprocal muscles during the motor preparation period: effect of movement repetition

Suzuki M, Suzuki T, Tanaka S, Sugawara K, Hamaguchi T

Neuroreport 12 ( 30 ) 856 - 862 2019.08 [Refereed]

Change-Driven M100 Component in the Bilateral Secondary Somatosensory Cortex: A Magnetoencephalographic Study.

Yamashiro K, Sato D, Onishi H, Sugawara K, Otsuru N, Kirimoto H, Nakazawa S, Yamazaki Y, Shirozu H, Maruyama A

Brain topography 32 ( 3 ) 435 - 444 2019.05 [Refereed] [International journal]

Our previous demonstration that the M100 somatosensory evoked magnetic field (SEF) has a similar temporal profile, dipole orientation and source location whether induced by activation (ON-M100) or deactivation (OFF-M100) of electrical stimulation suggests a common cortical system to detect sensory change. While we have not recorded such change-driven components earlier than M100 using electrical stimulation, clear M50 responses were reported using both ON and OFF mechanical stimulation (Onishi et al. in Clin Neurophysiol 121:588-593, 2010). To examine the significance of M50 and M100 in reflecting the detection of somatosensory changes, we recorded these waveforms in 12 healthy subjects (9 males and 3 females) by magnetoencephalography in response to mechanical stimulation from a piezoelectric actuator. Onset and offset (ON and OFF) stimuli were randomly presented with three preceding steady state (PSS) durations (0.5, 1.5 and 3 s) in one consecutive session. Results revealed that (i) onset and offset somatosensory events elicited clear M50 and M100 components; (ii) M50 and M100 components had distinct origins, with M50 localised to the contralateral primary somatosensory cortex (cS1) and M100 to the bilateral secondary somatosensory cortex (iS2, cS2); and (iii) the amplitude of M50 in cS1 was independent of the PSS durations, whereas that of M100 in S2 was dependent on the PSS durations for both ON and OFF events. These findings suggest that the M50 amplitude in cS1 reflects the number of activated mechanoreceptors during Onset and Offset, whereas the M100 amplitude in S2 reflects change detection based on sensory memory for Onset and Offset stimuli at least in part. We demonstrated that the M50 in cS1 and M100 in S2 plays different roles in the change detection system in somatosensory modality.

DOI PubMed

Effect of muscle contraction strength on gating effect —An MEG study—

Sugawara Kazuhiro

JAPANESE JOURNAL OF PHYSICAL THERAPY FUNDAMENTALS 21 ( 1 ) 63 - 68 2018 [Refereed]

Authorship： Lead author , Corresponding author

Electrical Stimulation of Denervated Rat Skeletal Muscle Ameliorates Bone Fragility and Muscle Loss in Early-Stage Disuse Musculoskeletal Atrophy.

Tamaki H, Yotani K, Ogita F, Hayao K, Nakagawa K, Sugawara K, Kirimoto H, Onishi H, Kasuga N, Yamamoto N

Calcif Tissue Int Apr; 100 ( 4 ) 420 - 430 2017.02 [Refereed]

Cortical oxyhemoglobin elevation persists after moderate-intensity cycling exercise: A near-infrared spectroscopy study

Tsubaki A,, Takehara N, Sato D, Morishita S, Tokunaga Y, Sugawara K, Kojima S, Tamaki H, Yamazaki Y, Onishi H

Advances in Experimental Medicine and Biology ( Springer New York LLC ) 977 261 - 268 2017 [Refereed]

Near-infrared spectroscopy (NIRS) can measure cortical activity during gross motor tasks based on the cerebral hemodynamic response. Although some reports suggest that cycling exercise improves cortical oxygenation, its after-effects are unknown. We examined the after-effects of low- and moderate-intensity cycling exercise on cortical oxygenation. Ten healthy volunteers (mean age 21.3 ± 0.7 years 4 women) underwent cycle ergometer exercise at 30% or 50% of VO2peak for 20 min, followed by an 8-min post-exercise rest (PER). O2Hb levels of the supplementary motor area (SMA) and sensorimotor cortex (SMC) were recorded using a near-infrared spectroscopy system. Skin blood flow (SBF) and mean arterial pressure (MAP) were continuously measured. The peak values of O2Hb between exercise and PER were compared. The O2Hb, SBF, and MAP increased in the exercise phase. SBF degraded over time, and MAP decreased immediately after exercise. The O2Hb decreased immediately and increased again in the PER. There were no significant differences between exercise and PER in the SMC in the 30% VO2peak experiment or in the SMA and SMC in the 50% VO2peak experiment. The O2Hb in the motor-related area was elevated during both exercise and PER especially in the 50% VO2peak experiment.

DOI PubMed

Effect of muscle contraction strength on gating of somatosensory magnetic fields

Sugawara K, Onishi H, Yamashiro K, Kotan S, Kojima S, Miyaguchi S, Tsubaki A, Kirimoto H, Tamaki H, Shirozu H, Kameyama S

Experimental Brain Research ( SPRINGER ) 234 ( 11 ) 3389 - 3398 2016.11 [Refereed]

Authorship： Lead author , Corresponding author

Afferent somatosensory information is modulated before the afferent input arrives at the primary somatosensory cortex during voluntary movement. The aim of the present study was to clarify the effect of muscular contraction strength on somatosensory evoked fields (SEFs) during voluntary movement. In addition, we examined the differences in gating between innervated and non-innervated muscle during contraction. We investigated the changes in gating effect by muscular contraction strength and innervated and non-innervated muscles in human using 306-channel magnetoencephalography. SEFs were recorded following the right median nerve stimulation in a resting condition and during isometric muscular contractions from 10 % electromyographic activity (EMG), 20 and 30 % EMG of the right extensor indicis muscle and abductor pollicis brevis muscle. Our results showed that the equivalent current dipole (ECD) strength for P35m decreased with increasing strength of muscular contraction of the right abductor pollicis brevis muscle. However, changes were observed only at 30 % EMG contraction level of the right extensor indicis muscle, which was not innervated by the median nerve. There were no significant changes in the peak latencies and ECD locations of each component in all conditions. The ECD strength did not differ significantly for N20m and P60m regardless of the strength of muscular contraction and innervation. Therefore, we suggest that the gating of SEF waveforms following peripheral nerve stimulation was affected by the strength of muscular contraction and innervation of the contracting muscle.

DOI

Effect of Range and Angular Velocity of Passive Movement on Somatosensory Evoked Magnetic Fields

Sugawara K, Onishi H, Yamashiro K, Kojima S, Miyaguchi S, Kotan S, Tsubaki A, Kirimoto H, Tamaki H, Shirozu H, Kameyama S

Brain Topography ( SPRINGER ) 29 ( 5 ) 693 - 703 2016.09 [Refereed]

Authorship： Lead author , Corresponding author

To clarify characteristics of each human somatosensory evoked field (SEF) component following passive movement (PM), PM1, PM2, and PM3, using high spatiotemporal resolution 306-channel magnetoencephalography and varying PM range and angular velocity. We recorded SEFs following PM under three conditions [normal range-normal velocity (NN), small range-normal velocity (SN), and small range-slow velocity (SS)] with changing movement range and angular velocity in 12 participants and calculated the amplitude, equivalent current dipole (ECD) location, and the ECD strength for each component. All components were observed in six participants, whereas only PM1 and PM3 in the other six. Clear response deflections at the ipsilateral hemisphere to PM side were observed in seven participants. PM1 amplitude was larger under NN and SN conditions, and mean ECD location for PM1 was at primary motor area. PM3 amplitude was larger under SN condition and mean ECD location for PM3 under SS condition was at primary somatosensory area. PM1 amplitude was dependent on the angular velocity of PM, suggesting that PM1 reflects afferent input from muscle spindle, whereas PM3 amplitude was dependent on the duration. The ECD for PM3 was located in the primary somatosensory cortex, suggesting that PM3 reflects cutaneous input. We confirmed the hypothesis for locally distinct generators and characteristics of each SEF component.

DOI

Inhibitory effect of intensity and interstimulus interval of conditioning stimuli on somatosensory evoked magnetic fields

Onishi H, Sugawara K, Yamashiro K, Sato D, Kirimoto H, Tamaki H, Shirozu H, Kameyama S

European Journal of Neuroscience ( WILEY-BLACKWELL ) 44 ( 4 ) 2104 - 2113 2016.08 [Refereed]

Magnetoencephalography (MEG) recordings were performed to investigate the inhibitory effects of conditioning stimuli with various types of interstimulus intervals (ISIs) or intensities on somatosensory evoked magnetic fields (SEFs) using a 306-ch whole-head MEG system. Twenty-three healthy volunteers participated in this study. Electrical stimuli were applied to the right median nerve at the wrist. Six pulse trains with ISIs of 500ms were presented in Experiment 1. A paired-pulse paradigm with three kinds of conditioning stimulus (CON) intensities, 500ms before the test stimulus (TS), was applied in Experiment 2. Finally, three CONs 500 or 1000ms before TS were presented in Experiment 3. Three main SEF deflections (N20m, P35m, and P60m) were observed, and the source activities of P35m and P60m significantly decreased after the 2nd pulse of a six pulse trains. These source activities also significantly decreased with increasing intensity of CON. In addition, these attenuations of source activities were affected by CON-CON or CON-TS intervals. These results indicated that the source activities were modulated by the intensity and ISIs of CONs. Furthermore, P35m after the stimulation were very sensitive to CONs; however, the attenuation of P60m after the stimulation lasted for a longer period than that of P35m. Our findings suggest that the conditioning stimulation had inhibitory effects on subsequent evoked cortical responses for more than 500ms. Our results also provide important clues about the nature of short-latency somatosensory responses in human studies.

DOI

Effect of Transcranial Direct Current Stimulation over the Primary Motor Cortex on Cerebral Blood Flow: A Time Course Study Using Near-infrared Spectroscopy

Takai H, Tsubaki A, Sugawara K, Miyaguchi S, Oyanagi K, Matsumoto M, Onishi H, Yamamoto N

Oxygen transport to tissue XXXVII ( SPRINGER ) 876 335 - 341 2016 [Refereed]

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that is applied during stroke rehabilitation. The purpose of this study was to examine diachronic intracranial hemodynamic changes using near-infrared spectroscopy (NIRS) during tDCS applied to the primary motor cortex (M1). Seven healthy volunteers were tested during real stimulation (anodal and cathodal) and during sham stimulation. Stimulation lasted 20 min and NIRS data were collected for about 23 min including the baseline. NIRS probe holders were positioned over the entire contralateral sensory motor area. Compared to the sham condition, both anodal and cathodal stimulation resulted in significantly lower oxyhemoglobin (O(2)Hb) concentrations in the contralateral premotor cortex (PMC), supplementary motor area (SMA), and M1 (p< 0.01). Particularly in the SMA, the O(2)Hb concentration during anodal stimulation was significantly lower than that during the sham condition (p< 0.01), while the O(2)Hb concentration during cathodal stimulation was lower than that during anodal stimulation (p< 0.01). In addition, in the primary sensory cortex, the O(2)Hb concentration during anodal stimulation was significantly higher than the concentrations during both cathodal stimulation and the sham condition (p< 0.05). The factor of time did not demonstrate significant differences. These results suggest that both anodal and cathodal tDCS cause widespread changes in cerebral blood flow, not only in the area immediately under the electrode, but also in other areas of the cortex.

DOI

Cortical magnetic activation following voluntary movement and several types of somatosensory stimulation.

Onishi H, Sugawara K, Yamashiro K, Sato D, Kirimoto H, Tamaki H, Shirozu H, Kameyama S

J Phys Fitness Sports Med 5 275 - 286 2016 [Refereed]

Correlation between the cerebral oxyhaemoglobin signal and physiological signals during cycling exercise: A near- infrared spectroscopy study

Tsubaki A, Takai H, Oyanagi K, Kojima S, Tokunaga Y, Miyaguchi S, Sugawara K, Sato D, Tamaki H, Onishi H

Advances in Experimental Medicine and Biology ( Springer New York LLC ) 923 ( 23 ) 159 - 166 2016 [Refereed]

Near-infrared spectroscopy (NIRS) is a widely used noninvasive method for measuring human brain activation based on the cerebral haemodynamic response. However, systemic changes can influence the signal’s parameters. Our study aimed to investigate the relationships between NIRS signals and skin blood flow (SBF) or blood pressure during dynamic movement. Nine healthy volunteers (mean age, 21.3 ± 0.7 years 6 women) participated in this study. The oxyhaemoglobin (O 2 Hb) signal, SBF, and mean arterial pressure (MAP) were measured while the volunteers performed multi-step incremental exercise on a bicycle ergometer, at workloads corresponding to 30, 50, and 70 % of peak oxygen consumption (VO2 peak) for 5 min. The Pearson’s correlation coefficients for the O2 Hb signal and SBF at 50 and 70 % VO2 peak were 0.877 (P < 0.01) and −0.707 (P < 0.01), respectively. The correlation coefficients for O2 Hb and MAP during warm-up, 30 % VO2 peak, and 50 % VO2 peak were 0.725 (P < 0.01), 0.472 (P < 0.01), and 0.939 (P < 0.01), respectively. Changes in the state of the cardiovascular system influenced O2 Hb signals positively during low and moderate-intensity exercise, whereas a negative relationship was observed during high-intensity exercise. These results suggest that the relationship between the O2 Hb signal and systemic changes is affected by exercise intensity.

DOI PubMed

Changes in Cortical Oxyhaemoglobin Signal During Low-Intensity Cycle Ergometer Activity: A Near-Infrared Spectroscopy Study

Tsubaki A, Takai H, Kojima S, Miyaguchi S, Sugawara K, Sato D, Tamaki H, Onishi H

Oxygen transport to tissue XXXVII ( SPRINGER ) 876 79 - 85 2016 [Refereed]

Near-infrared spectroscopy (NIRS) is a widely used non-invasive method for measuring human brain activation based on the cerebral hemodynamic response during gross motor tasks. However, systemic changes can influence measured NIRS signals. We aimed to determine and compare time-dependent changes in NIRS signal, skin blood flow (SBF), and mean arterial pressure (MAP) during low-intensity, constant, dynamic exercise. Nine healthy volunteers (22.1 +/- 1.7 years, 3 women) participated in this study. After a 4-min pre-exercise rest and a 4-min warm-up, they exercised on a bicycle ergometer at workloads corresponding to 30 % VO2 peak for 20 min. An 8-min rest period followed the exercise. Cortical oxyhaemoglobin signals (O(2)Hb) were recorded while subjects performed the exercise, using an NIRS system. Changes in SBF and MAP were also measured during exercise. O(2)Hb increased to 0.019 mM cm over 6 min of exercise, decreased slightly from 13 min towards the end of the exercise. SBF continued to increase over 16 min of the exercise period and thereafter decreased till the end of measurement. MAP fluctuated from -1.0 to 7.1 mmHg during the exercise. Pearson's correlation coefficients between SBF and O(2)Hb, and MAP and O(2)Hb differed in each time phase, from -0.365 to 0.713. During low-intensity, constant, dynamic exercise, the profile of changes in measurements of O(2)Hb, SBF, and MAP differed. These results suggested that it is necessary to confirm the relationship between O(2)Hb and systemic factors during motor tasks in order to detect cortical activation during gross motor tasks.

DOI

Regional Changes in Cerebral Oxygenation Passive Movement Measured by Functional Near-infrared Spectroscopy

Sugawara K, Onishi H, Tsubaki A, Takai H, Tokunaga Y, Tamaki H

Frontiers in human neuroscience ( FRONTIERS MEDIA SA ) 9 ( 9 ) doi: 10.3389/fnhum.2015.00641 2015.11 [Refereed]

Authorship： Lead author , Corresponding author

The aim of this study is to investigate the influence of passive movement repetition frequency at 1.5-Hz and 1-Hz on changes in cerebral oxygenation and assess the temporal properties of these changes using functional near-infrared spectroscopy (fNIRS). No significant differences in systemic hemodynamics were observed between resting and passive movement phases for either 1.5-Hz or 1-Hz trial. Changes in cortical oxygenation as measured by fNIRS in bilateral supplementary motor cortex (SMC), left primary motor cortex (M1), left primary somatosensory cortex (Si), and left posterior association area (PM) during passive movement of the right index finger revealed greater cortical activity at only 1.5-Hz movement frequency. However, there were no significant differences in the time for peak oxyhemoglobin (oxyHb) among regions (bilateral SMC, 206.4 +/- 14.4s; left M1, 199.1 +/- 14.8s; left S1, 207.3 +/- 9.4s; left PM, 219.1 +/- 10.2s). Therefore, our results that passive movement above a specific frequency may be required to elicit a changed in cerebral oxygenation, and the times of peak Delta oxyHb did not differ significantly among measured regions.

DOI

Skill-Specific Changes in Somatosensory Nogo Potentials in Baseball Players

Yamashiro K, Sato D, Onishi H, Sugawara K, Nakazawa S, Shimojo H, Akatsuka K, Nakata H, Maruyama A

Plos One ( PUBLIC LIBRARY SCIENCE ) 10 ( 11 ) doi: 10.1371/journal.pone.0142 2015.11 [Refereed]

Athletic training is known to induce neuroplastic alterations in specific somatosensory circuits, which are reflected by changes in somatosensory evoked potentials and event-related potentials. The aim of this study was to clarify whether specific athletic training also affects somatosensory Nogo potentials related to the inhibition of movements. The Nogo potentials were recorded at nine cortical electrode positions (Fz, Cz, Pz, F3, F4, C3, C4, P3 and P4) in 12 baseball players (baseball group) and in 12 athletes in sports, such as track and field events and swimming, that do not require response inhibition, such as batting for training or performance (sports group). The Nogo potentials and Go/Nogo reaction times (Go/Nogo RTs) were measured under a somatosensory Go/Nogo paradigm in which subjects were instructed to rapidly push a button in response to stimulus presentation. The Nogo potentials were obtained by subtracting the Go trial from the Nogo trial. The peak Nogo-N2 was significantly shorter in the baseball group than that in the sports group. In addition, the amplitude of Nogo-N2 in the frontal area was significantly larger in the baseball group than that in the sports group. There was a significant positive correlation between the latency of Nogo-N2 and Go/Nogo RT. Moreover, there were significant correlations between the Go/Nogo RT and both the amplitude of Nogo-N2 and Nogo-P3 (i.e., amplitude of the Nogo-potentials increases with shorter RT). Specific athletic training regimens may induce neuroplastic alterations in sensorimotor inhibitory processes.

DOI

Effect of electrical stimulation-induced muscle force and streptomycin treatment on muscle and trabecular bone mass in early-stage disuse musculoskeletal atrophy

Tamaki H, Yotani K, Ogita F, Sugawara K, Kirimto H, Onishi H, Kasuga N, Yamamoto N

Journal of musculoskeletal & neuronal interactions ( JMNI ) 15 ( 3 ) 270 - 278 2015.09 [Refereed]

Objectives: The aim was to determine whether daily muscle electrical stimulation (ES) and streptomycin treatment would have positive or negative effects on trabecular bone mass in disuse rats. Methods: Seven-week-old male F344 rats were randomly divided into five groups of eight animals each: an age-matched control group (CON); a sciatic denervation group (DN); a DN + direct electrical stimulation group (DN+ES); a DN + streptomycin treatment group (DN+SM); and a DN+ES+SM group. The tibialis anterior (TA) muscles in all ES groups were stimulated with 16mA at 10Hz for 30 min/day, six days/week, for one week. Bone volume and structure were evaluated using micro-CT, and histological examinations of the tibiae were performed. Results: Direct ES significantly reduced the disuse-induced trabecular bone loss. Osteoid thickness were also significantly greater in the ES groups than in the DN group. Micro CT and histomorphological parameters were significantly lower in the DN+ES+SM group than in the DN+ES group, while there were no significant differences between the DN and DN+SM groups. Conclusions: These results suggest that ES-induced muscle force reduced trabecular bone loss, and streptomycin treatment did not induce bone loss, but attenuated the effects of ES-induced muscle force on reducing the loss of disused bone.

Effects of cathodal transcranial direct current stimulation to primary somatosensory cortex on short- latency afferent inhibition

Kojima S, Onishi H, Miyaguchi S, Kotan S, Sugawara K, Kirimoto H, Tamaki H

Neuroreport ( LIPPINCOTT WILLIAMS & WILKINS ) 26 ( 11 ) 634 - 637 2015.08 [Refereed]

The aim of this study was to investigate the effects of cathodal transcranial direct current stimulation (tDCS) applied over the primary somatosensory cortex (S1) on short-interval afferent inhibition (SAI). Thirteen healthy individuals participated in this study. Cathodal tDCS was applied for 15min at 1mA over the left S1. Motor-evoked potentials (MEPs) were measured from the right first dorsal interosseous muscle in response to transcranial magnetic stimulation (TMS) of the left motor cortex before tDCS (pre), immediately after tDCS (immediately), and 15min after tDCS (post-15min). SAI was evaluated by measuring MEPs in response to TMS pulses applied 40ms after peripheral electrical stimulation of the index finger. For each measurement period (pre, immediately, and post-15min), MEP amplitude was significantly smaller when TMS followed index finger stimulation (SAI condition) than when TMS was delivered alone (single TMS) (P<0.01), indicating expression of SAI. The MEP ratio (MEP of SAI/MEP of single TMS) at post-15min was significantly larger than that of pre (P<0.05), indicating suppression of SAI. However, no significant difference was observed between pre and immediately, and immediately and post-15min. These results suggest that cathodal tDCS applied over the S1 causes a decrease in S1 excitability following peripheral electrical stimulation and cathodal tDCS applied over the S1 decreased the inhibitory effects of SAI. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

DOI

Depression of corticomotor excitability after muscle fatigue induced by electrical stimulation and voluntary contraction

Kotan S, Kojima S, Miyaguchi S, Sugawara K, Onishi H

Frontiers in human neuroscience ( FRONTIERS RESEARCH FOUNDATION ) 9 ( 9 ) doi: 10.3389 2015.06 [Refereed]

In this study, we examined the effect of muscle fatigue induced by tetanic electrical stimulation (ES) and submaximal isometric contraction on corticomotor excitability. Experiments were performed in a cross over design. Motor evoked potentials (MEPs) were elicited by transcranial magnetic stimulation (TMS). Corticomotor excitability was recorded before and after thumb opposition muscle fatigue tasks, in which 10% of the maximal tension intensity was induced by tetanic ES or voluntary contraction (VC). The participants were 10 healthy individuals who performed each task for 10 min. Surface electrodes placed over the abductor pollicis brevis (APB) muscle recorded MEPs. F- and M-waves were elicited from APB by supramaximal ES of the median nerve. After the tetanic ES- and VC tasks, MEP amplitudes were significantly lower than before the task. However, F- and M-wave amplitudes remained unchanged. These findings suggest that corticospinal excitability is reduced by muscle fatigue as a result of intracortical inhibitory mechanisms. Our results also suggest that corticomotor excitability is reduced by muscle fatigue caused by both VC and tetanic ES.

DOI

Maximum Power During Vertical Jump and Isometric Knee Extension Torque Alter Mobility Performance: A Cross-Sectional Study of Healthy Individuals.

Tsubaki A, Kubo M, Kobayashi R, Jigami H, Sugawara K, Takahashi HE

PM R 29 doi: 10.1016 2015.04 [Refereed]

Effect of Changes in Stimulus Site on Activation of the Posterior Parietal Cortex

Yamashiro K, Sato D, Onishi H, Sugawara K, Nakazawa S, Kameyama S, Maruyama A

Brain Topography ( SPRINGER ) 28 ( 2 ) 261 - 268 2015.03 [Refereed]

A previous functional magnetic resonance imaging study elucidated the specific activity of the inferior parietal lobe (IPL) during a two-point discrimination task compared with that during an intensity discrimination task Akatsuka et al. (Neuroimage 40: 852-858, 2008). If the posterior parietal cortex (PPC), including IPL, is responsible for detecting changes in stimulus sites, PPC activity depends on the level of change at stimulus sites. The aim of this study was to clarify whether a particular site exists that could detect changes in stimulus sites using the oddball paradigm. Somatosensory-evoked magnetic fields were recorded in 10 right-handed subjects. Three oddball conditions were performed by all subjects, with the probability of deviant and standard stimuli being 20 and 80 %, respectively, under all three conditions. Deviant stimuli were always presented to the second digit of the hand and standard stimuli were presented to the first (small deviance: SD) and fifth digits (medium deviance: MD) of the hand and the first digit of the toe (large deviance: LD). Inter-stimulus intervals were set at 500 ms. A brain electrical source analysis showed that activities of areas 1 and 3b elicited by the deviant stimuli were not significantly different among the three conditions. In contrast, PPC activity was significantly greater for LD than for SD and MD. PPC activity tended to increase with greater deviance at stimulus sites, but activities of areas 1 and 3b did not differ. These findings suggest that PPC may have a functional role in automatic change detection systems with regard to deviance of stimulus sites.

DOI

Time Course of Change in Movement Structure During Learning of Goal-Directed Movement

Suzuki M, Kirimoto H, Sugawara K, Kasahara Y, Kawaguchi T, Ishizaka I, Yamada S, Matsunaga A, Fukuda M, Onishi H

Journal of medical and biological engineering ( SPRINGER HEIDELBERG ) 35 ( 1 ) 113 - 124 2015.02 [Refereed]

Primary and secondary submovements are important in human movements. The purpose of this study was to examine the time course of changes in kinematics and electromyography (EMG) parameters for primary and secondary submovements associated with the learning of a goal-directed aiming movement task. The subjects comprised 9 neurologically normal adults. They were instructed to make horizontal planar movements of elbow flexion that were both fast and accurate. The learning session comprised 20 blocks of 10 movements. Our research found that the kinematics- and EMG-related parameters of the antagonistic triceps brachii muscle gradually changed over the course of the learning period and reached a plateau that fitted an exponential function. However, the EMG parameters of the agonistic biceps brachii muscle did not markedly change. Moreover, the kinematics- and EMG-related parameters for the primary and secondary submovements varied at different rates during the motor learning. Our findings may facilitate the understanding of the learning of a goal-directed aiming movement in sports and rehabilitation settings.

DOI

The effect of anodal transcranial direct current stimulation over the primary motor or somatosensory cortices on somatosensory evoked magnetic fields

Kazuhiro Sugawara, Hideaki Onishi, Koya Yamashiro, Sho Kojima, Shota Miyaguchi, Hikari Kirimoto, Atsuhiro Tsubaki, Hiroyuki Tamaki, Hiroshi Shirozu, Shigeki Kameyama

CLINICAL NEUROPHYSIOLOGY ( ELSEVIER IRELAND LTD ) 126 ( 1 ) 60 - 67 2015.01 [Refereed]

Objectives: The purpose of this study was to investigate the effect of anodal transcranial direct-current stimulation (tDCS) applied over the primary motor (M1) or the primary somatosensory (S1) cortices on somatosensory evoked magnetic fields (SEFs) following median nerve stimulation. Methods: Anodal tDCS was applied for 15 min on the left motor or somatosensory cortices at 1 mA. SEFs were recorded following right median nerve stimulation using a magnetoencephalography (MEG) system before and after the application of tDCS. SEFs was measured and compared before and after tDCS was applied over M1 or S1. Results: The source strengths for the P35m and P60m increased after tDCS was applied over M1 and that for the P60m increased after tDCS was applied over S1. The mean equivalent current dipole (ECD) location for the P35m was located significantly anterior to that of the N20m, but only during post 1 (10-20 min after tDCS was applied over M1). Conclusion: Our results indicated that the anodal tDCS applied over M1 affected the P35m and P60m sources on SEF components, while that applied over S1 influenced the P60m source. Significance: We demonstrated anodal tDCS applied over M1 or S1 can modulate somatosensory processing and components of SEFs, confirming the hypothesis for locally distinct generators of the P35m and P60m sources. (C) 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

DOI

経頭蓋直流電流刺激の効果的な介入方法の検討－電極貼付部位および電流強度の影響－

宮口翔太, 大西秀明, 小島翔, 菅原和広, 桐本光,他

理学療法学 ( Japanese Society of Physical Therapy ) 42 ( 3 ) 213 - 219 2015 [Refereed]

Purpose: In the present study, we investigated whether anodal transcranial direct current stimulation (tDCS) applied to the primary motor cortex (Ml) is affected differential of current intensity or electrode position. Methods: Nine healthy subjects participated in this study. tDCS was delivered using a pair of salinesoaked surface sponge electrodes for 10 min. The anodal electrode was placed on the scalp above the left M1. The cathodal electrode was placed over the orbit or on the scalp above the right M1 (unilateral tDCS and bilateral tDCS, respectively). All subjects underwent the following four interventions: unilateral tDCS delivered with 1.0 mA and 2.0 mA (unilateral_1.0 mA condition and unilateral_2.0 mA condition, respectively) and bilateral tDCS delivered with 1.0 mA and 2.0 mA (bilateral_1.0 mA condition and bilateral_2.0 mA condition, respectively). Motor evoked potentials (MEPs) were recorded from the right first dorsal interosseous before and 2 min and 10 min after the intervention. Results: Under the bilateral_2.0 mA condition, the MEP amplitudes at 2 min and 10 min after the intervention were significantly increased compared with those before the intervention. However, under the other three conditions, the MEP amplitudes remained unchanged. Conclusion: These results demonstrate that anodal tDCS is highly affected differential of current intensity or electrode position.

DOI CiNii

Plasticity of human motor associate and primary sensorimotor cortices induced by tDCS.

Kirimoto H, Miyaguchi S, Onishi H, Suzuki M, Sugawara K, Matsumoto T, Tamaki H

Adv Exerc Sports Physiol ( Japan Society of Exercise and Sports Physiology ) 21 ( 3 ) 47 - 52 2015 [Refereed]

Nitsche and Paulus (2000) first described the efficacy of transcranial direct current stimulation (tDCS) for functional modulation of the human motor cortex. Since then, tDCS has been an increasingly useful technique for noninvasive brain stimulation that can be used not only for examining cortical function in healthy subjects, but also for facilitating treatments for various neurological disorders. The advantages of tDCS over other noninvasive brain stimulation methods include its ease of use, large electrode size allowing effect over a larger neural network, sham mode allowing controlled experiments and randomized controlled clinical trials. In this symposium, we plan to introduce the three points of studies about plastic changes of motor association cortex excitability induced by tDCS. 1) Transcranial direct current stimulation over the motor association cortex induces plastic changes in the ipsilateral primary motor and somatosensory cortices 2) The effects of cathodal transcranial direct current stimulation of the supplementary motor area on the function of anticipatory postural adjustments 3) Corticomotor excitability induced by anodal transcranial direct current stimulation with and without non-exhaustive movement

CiNii

Effects of cathodal transcranial direct current stimulation to primary somatosensory cortex on short-latency afferent inhibition

Kojima S, Onishi H, Miyaguchi S, Kotan S, Sugawara K, Kirimoto H, Tamaki H

Neuroreport 15 ( 3 ) 270 - 278 2015 [Refereed]

視覚反応課題の反復練習が大脳皮質情報処理過程に及ぼす影響

菅原和広

理学療法学 ( Japanese Society of Physical Therapy ) 41 ( 8 ) 552 - 554 2014.12 [Refereed]

DOI CiNii

No relation between afferent facilitation induced by digital nerve stimulation and the latency of cutaneomuscular reflexes and somatosensory evoked magnetic fields

Sho Kojima, Hideaki Onishi, Kazuhiro Sugawara, Shota Miyaguchi, Hikari Kirimoto, Hiroyuki Tamaki, Hiroshi Shirozu, Shigeki Kameyama

FRONTIERS IN HUMAN NEUROSCIENCE ( FRONTIERS RESEARCH FOUNDATION ) 8 ( 8 ) doi: 10.3389/fnhum.2014.01023 2014.12 [Refereed]

Primary motor cortex (M1) excitability can be assessed using transcranial magnetic stimulation (TMS) and can be modulated by a conditioning electrical stimulus delivered to a peripheral nerve prior to TMS. This is known as afferent facilitation (AF). The aim of this study was to determine whether AF can be induced by digital nerve stimulation and to evaluate the relation between the interstimulus interval (ISI) required for AF and the latency of the E2 component of the cutaneomuscular reflex (CMR) and the prominent somatosensory evoked field (SEF) deflection that occurs approximately 70 ms after digital nerve stimulation (P60m). Stimulation of the digital nerve of the right index finger was followed, at various time intervals, by single-pulse TMS applied to the contralateral hemisphere. The ISI between digital nerve stimulation and TMS was 20, 30, 40, 50, 60, 70, 80, 100, 140, 180, 200, or 220 ms. Single-pulse TMS was performed alone as a control. SEFs were recorded following digital nerve stimulation of the index finger, and the equivalent current dipole of prominent deflections that occurred around 70 ms after the stimulation was calculated. CMRs were recorded following digital nerve stimulation during muscle contraction. Motor evoked potentials (MEPs) were facilitated at an ISI between 50 and 100 ms in 11 of 13 subjects, and the facilitated MEP amplitude was larger than the unconditioned MEP amplitude (p < 0.01). There was no significant correlation between the ISI at which AF was maximal and the latency of the P60m component of the SEF (r = -0.50, p = 0.12) or the E2 component of the CMR (r = -0.54, p = 0.88). These results indicate that the precise ISI required for AF cannot be predicted using SEF or CMR.

DOI

Effect of Transcranial Static Magnetic Field Stimulation Over the Sensorimotor Cortex on Somatosensory Evoked Potentials in Humans

Hikari Kirimoto, Hiroyuki Tamaki, Takuya Matsumoto, Kazuhiro Sugawara, Makoto Suzuki, Mineo Oyama, Hideaki Onishi

BRAIN STIMULATION ( ELSEVIER SCIENCE INC ) 7 ( 6 ) 836 - 840 2014.11 [Refereed]

Background: The motor cortex in the human brain can be modulated by the application of transcranial static magnetic field stimulation (tSMS) through the scalp. However, the effect of tSMS on the excitability of the primary somatosensory cortex (S1) in humans has never been examined. Objective: This study was performed to investigate the possibility of non-invasive modulation of S1 excitability by the application of tSMS in healthy humans. Methods: tSMS and sham stimulation over the sensorimotor cortex were applied to 10 subjects for periods of 10 and 15 min. Somatosensory evoked potentials (SEPs) following right median nerve stimulation were recorded before and immediately after, 5 min after, and 10 min after tSMS from sites C3' and F3 of the international 10-20 system of electrode placement. In another session, SEPs were recorded from 6 of the 10 subjects every 3 min during 15 min of tSMS. Results: Amplitudes of the N20 component of SEPs at C3' significantly decreased immediately after 10 and 15 min of tSMS by up to 20%, returning to baseline by 10 min after intervention. tSMS applied while recording SEPs every 3 min and sham stimulation had no effect on SEP. Conclusions: tSMS is able to modulate cortical somatosensory processing in humans, and thus might be a useful tool for inducing plasticity in cortical somatosensory processing. Lack of change in the amplitude of SEPs with tSMS implies that use of peripheral nerve stimulation to cause SEPs antagonizes alteration of the function of membrane ion channels during exposure to static magnetic fields. (C) 2014 Elsevier Inc. All rights reserved.

DOI

Induction of cortical plasticity for reciprocal muscles by paired associative stimulation

Makoto Suzuki, Hikari Kirimoto, Kazuhiro Sugawara, Makoto Watanabe, Shinobu Shimizu, Ikuyo Ishizaka, Sumio Yamada, Atsuhiko Matsunaga, Michinari Fukuda, Hideaki Onishi

BRAIN AND BEHAVIOR ( JOHN WILEY & SONS INC ) 4 ( 6 ) 822 - 832 2014.11 [Refereed]

Background: Paired associative stimulation (PAS) is widely used to induce plasticity in the human motor cortex. Although reciprocal inhibition of antagonist muscles plays a fundamental role in human movements, change in cortical circuits for reciprocal muscles by PAS is unknown. Methods: We investigated change in cortical plasticity for reciprocal muscles during PAS. PAS consisted of 200 pairs of peripheral electric stimulation of the right median nerve at the wrist at a frequency of 0.25 Hz followed by transcranial magnetic stimulation of the left M1 at the midpoint between the center of gravities of the flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles. Measures of motor cortical excitability included resting motor threshold (RMT), GABA(A)-mediated short-interval intracortical inhibition (SICI), and GABA(B)-mediated long-interval intracortical inhibition (LICI). Results: Motor evoked potential amplitude-conditioned LICI for the FCR muscle was significantly decreased after PAS (P = 0.020), whereas that for the ECR muscle was significantly increased (P = 0.033). Changes in RMT and SICI for the FCR and ECR muscles were not significantly different before and after PAS. Corticospinal excitability for both reciprocal muscles was increased during PAS, but GABA(B)-mediated cortical inhibitory functions for the agonist and antagonist muscles were reciprocally altered after PAS. Conclusion: These results implied that the cortical excitability for reciprocal muscles including GABA(B)-ergic inhibitory systems within human M1 could be differently altered by PAS.

DOI

Sensorimotor Modulation Differs with Load Type during Constant Finger Force or Position

Hikari Kirimoto, Hiroyuki Tamaki, Makoto Suzuki, Takuya Matsumoto, Kazuhiro Sugawara, Syo Kojima, Hideaki Onishi

PLOS ONE ( PUBLIC LIBRARY SCIENCE ) 9 ( 9 ) doi: 10.1371/journal.pone.0108 2014.09 [Refereed]

During submaximal isometric contraction, there are two different load types: production of a constant force against a rigid restraint (force task), and maintenance of position against a constant load (position task). Previous studies reported that the time to task failure during a fatigue task was twice as long in the force task compared with the position task. Sensory feedback processing may contribute to these differences. The purpose of the current study was to determine the influence of load types during static muscle contraction tasks on the gating effect, i. e., attenuation of somatosensory-evoked potentials (SEPs) and the cortical silent period (cSP). Ten healthy subjects contracted their right first dorsal interosseus muscle by abducting their index finger for 90 s, to produce a constant force against a rigid restraint that was 20% of the maximum voluntary contraction (force task), or to maintain a constant position with 10 degrees abduction of the metacarpophalangeal joint against the same load (position task). Somatosensory evoked potentials (SEPs) were recorded from C3' by stimulating either the right ulnar or median nerve at the wrist while maintaining contraction. The cortical silent period (cSP) was also elicited by transcranial magnetic stimulation. Reduction of the amplitude of the P45 component of SEPs was significantly larger during the position task than during the force task and under control rest conditions when the ulnar nerve, but not the median nerve, was stimulated. The position task had a significantly shorter cSP duration than the force task. These results suggest the need for more proprioceptive information during the position task than the force task. The shorter duration of the cSP during the position task may be attributable to larger amplitude of heteronymous short latency reflexes. Sensorimotor modulations may differ with load type during constant finger force or position tasks.

DOI

Motor Cortex-Evoked Activity in Reciprocal Muscles Is Modulated by Reward Probability

Makoto Suzuki, Hikari Kirimoto, Kazuhiro Sugawara, Mineo Oyama, Sumio Yamada, Jun-ichi Yamamoto, Atsuhiko Matsunaga, Michinari Fukuda, Hideaki Onishi

PLOS ONE ( PUBLIC LIBRARY SCIENCE ) 9 ( 3 ) doi: 10.1371/journal.pone.0090 2014.03 [Refereed]

Horizontal intracortical projections for agonist and antagonist muscles exist in the primary motor cortex (M1), and reward may induce a reinforcement of transmission efficiency of intracortical circuits. We investigated reward-induced change in M1 excitability for agonist and antagonist muscles. Participants were 8 healthy volunteers. Probabilistic reward tasks comprised 3 conditions of 30 trials each: 30 trials contained 10% reward, 30 trials contained 50% reward, and 30 trials contained 90% reward. Each trial began with a cue (red fixation cross), followed by blue circle for 1 s. The subjects were instructed to perform wrist flexion and press a button with the dorsal aspect of middle finger phalanx as quickly as possible in response to disappearance of the blue circle without looking at their hand or the button. Two seconds after the button press, reward/non-reward stimulus was randomly presented for 2-s duration. The reward stimulus was a picture of Japanese 10-yen coin, and each subject received monetary reward at the end of experiment. Subjects were not informed of the reward probabilities. We delivered transcranial magnetic stimulation of the left M1 at the midpoint between center of gravities of agonist flexor carpi radialis (FCR) and antagonist extensor carpi radialis (ECR) muscles at 2 s after the red fixation cross and 1 s after the reward/non-reward stimuli. Relative motor evoked potential (MEP) amplitudes at 2 s after the red fixation cross were significantly higher for 10% reward probability than for 90% reward probability, whereas relative MEP amplitudes at 1 s after reward/non-reward stimuli were significantly higher for 90% reward probability than for 10% and 50% reward probabilities. These results implied that reward could affect the horizontal intracortical projections in M1 for agonist and antagonist muscles, and M1 excitability including the reward-related circuit before and after reward stimulus could be differently altered by reward probability.

DOI

Electrical stimulation of denervated rat skeletal muscle retards trabecular bone loss in early stages of disuse musculoskeletal atrophy

H. Tamaki, K. Tomori, K. Yotani, F. Ogita, K. Sugawara, H. Kirimto, H. Onishi, N. Yamamoto, N. Kasuga

Journal of Musculoskeletal Neuronal Interactions ( International Society of Musculoskeletal and Neuronal Interactions ) 14 ( 2 ) 220 - 228 2014 [Refereed]

Objectives: We aimed to determine the intensity of muscle stimulation required to prevent structural failure as well as bone and skeletal muscle loss after denervation-induced disuse. Methods: Seven-week-old rats (weight, 198-225 g) were randomly assigned to age-matched groups comprising control (CON), sciatic nerve denervation (DN) or direct electrical stimulation (ES) one day later [after denervation] with 4, 8 and 16 mA at 10 Hz for 30 min/day, six days/week, for one or three weeks. Bone architecture and mean osteoid thickness in histologically stained tibial sections and tension in tibialis anterior muscles were assessed at one and three weeks after denervation. Results: Direct ES with 16 mA generated 23-30% maximal contraction force. Denervation significantly decreased trabecular bone volume fraction, thickness and number, connectivity density and increased trabecular separation in the DN group at weeks one and three. Osteoid thickness was significantly greater in the ES16 group at week one than in the DN and other ES groups. Trabecular bone volume significantly correlated with muscle weight. Conclusions: Relatively low-level muscle contraction induced by low-frequency, high-intensity electrical muscle stimulation delayed trabecular bone loss during the early stages (one week after DN) of musculoskeletal atrophy due to disuse.

PubMed

Activation of the Human Premotor Cortex During Motor Preparation in Visuomotor Tasks

Kazuhiro Sugawara, Hideaki Onishi, Koya Yamashiro, Hikari Kirimoto, Atsuhiro Tsubaki, Makoto Suzuki, Hiroyuki Tamaki, Hiroatsu Murakami, Shigeki Kameyama

BRAIN TOPOGRAPHY ( SPRINGER ) 26 ( 4 ) 581 - 590 2013.10 [Refereed]

Authorship： Lead author , Corresponding author

Functional brain mapping studies in humans suggest that both motor and premotor cortices interact during movement execution. The aim of this study was to investigate whether the premotor cortex also participates in motor planning. We measured movement-related cerebral fields (MRCFs) using magnetoencephalography from the left hemisphere of 12 healthy right-handed participants during two simple visuomotor tasks cued by two visual stimuli S1 and S2. Participants performed a unilateral task in which they always extended the right index finger after S2 presentation regardless of the color of S1 and a bilateral task in which they extended either the right or left index finger after S2 presentation according to the color of S1. Significantly higher MRCF activity was observed during the 500 ms S1 to S2 interval in the bilateral task than in the unilateral task. In the bilateral task trials, the latency of the peak MRCF during the S1 to S2 interval was 343.9 +/- A 73.5 ms after S1 presentation and that of the peak of movement-evoked field 1 was 33.4 +/- A 3.9 ms after movement onset in the bilateral task. Equivalent current dipoles at the peak MRCF were significantly medial (9.2 +/- A 12.1 mm) and anterior (19.8 +/- A 6.9 mm) to the reference location in the somatosensory cortex (area 3b) established by median nerve stimulation. This location corresponds to the dorsal premotor cortex. These findings suggest that activation of the premotor cortex observed during the interstimulus interval may represent a neurophysiological marker of response selection.

DOI

Effect of the number of pins and inter-pin distance on somatosensory evoked magnetic fields following mechanical tactile stimulation

Hideaki Onishi, Kazuhiro Sugawara, Koya Yamashiro, Daisuke Sato, Makoto Suzuki, Hikari Kirimoto, Hiroyuki Tamaki, Hiroatsu Murakami, Shigeki Kameyama

BRAIN RESEARCH ( ELSEVIER SCIENCE BV ) 1535 78 - 88 2013.10 [Refereed]

Magnetoencephalography (MEG) recordings were collected to investigate the effect of the number of mechanical pins and inter-pin distance on somatosensory evoked magnetic fields (SEFs) following mechanical stimulation (MS). We used a 306-ch whole-head MEG system. SEFs were elicited through tactile stimuli with 1-, 2-, 3-, 4- and 8-pins using healthy participants. Tactile stimuli were applied to the tip of the right index finger. SEF following electrical stimulation of the index finger was recorded in order to compare the activity in the primary somatosensory cortex (S1) following MS. Prominent SEFs were recorded from the contralateral hemisphere approximately 54 ms (P50m) and 125 ms (P100m) after MS regardless of the number of pins. Equivalent current dipoles were located in the S1. The source activities for P50m and P100m significantly increased in tandem with the number of pins for MS. However, the increased ratios for the source activities according to the increase in the number of pins were significantly smaller than that induced by electrical stimulation, and when the number of the pins doubled from 1-pin to 2-pins, from 2-pins to 4-pins, and from 4-pins to 8-pins, Si activities increased by only 130%. Additionally, source activities significantly increased when the inter-pin distance increased from 2.4 to 7.2 mm. The number of stimulated receptors was considered to have increased with an increase in the inter-pin distance as well as an increase in the number of pins. These findings clarified the effect of the number of pins and inter-pin distance for MS on SEFs. (C) 2013 The Authors. Published by Elsevier B.V. All rights reserved.

DOI

Corticomotor excitability induced by anodal transcranial direct current stimulation with and without non-exhaustive movement

Shota Miyaguchi, Hideaki Onishi, Sho Kojima, Kazuhiro Sugawara, Atsuhiro Tsubaki, Hikari Kirimoto, Hiroyuki Tamaki, Noriaki Yamamoto

Brain Research 1529 83 - 91 2013.09 [Refereed]

We investigated whether anodal transcranial direct current stimulation (tDCS) applied to the motor cortex during non-exhaustive active or passive movements enhances corticomotor excitability after tDCS or whether it reduces post-exercise depression (PED) after non-exhaustive active or passive movements if PED was observed without tDCS. Nine healthy subjects participated in this study. Anodal tDCS with a current of 2 mA was applied to the left scalp over the primary motor area. All subjects underwent the following five interventions: tDCS delivered for 10 min during relaxation (tDCS condition) and repetitive voluntary and passive finger abduction-adduction movements, each performed without and with tDCS for 10 min (active condition, tDCS+active condition, passive condition, tDCS+passive condition). The active movements were performed at 10% maximum voluntary contraction. Motor evoked potentials (MEPs) were recorded from the right first dorsal interosseus muscle before the intervention (pre-intervention) and 2 and 10 min after the intervention (post-2 min and post-10 min, respectively). Under the tDCS condition, the MEP amplitudes at post-2 and -10 min were significantly increased compared with those before the intervention. Under the active, passive, and tDCS+active conditions, the MEP amplitudes at post-2 min were significantly decreased compared with those before the interventions. Under the tDCS+passive condition, the MEP amplitude remained unchanged. These results demonstrated that anodal tDCS did not reduce PED after active movements but after passive movements and that the anodal tDCS effects were highly dependent on the state of the subject during stimulation. © 2013 Elsevier B.V. All rights reserved.

DOI PubMed

Repeated practice of a Go/NoGo visuomotor task induces neuroplastic change in the human posterior parietal cortex: an MEG study

Kazuhiro Sugawara, Hideaki Onishi, Koya Yamashiro, Toshio Soma, Mineo Oyama, Hikari Kirimoto, Hiroyuki Tamaki, Hiroatsu Murakami, Shigeki Kameyama

EXPERIMENTAL BRAIN RESEARCH ( SPRINGER ) 226 ( 4 ) 495 - 502 2013.05 [Refereed]

Authorship： Lead author , Corresponding author

The posterior parietal cortex (PPC) is strongly related to task performance by evaluating sensory cues and visually guided movements. Sensorimotor processing is improved by task repetition as indicated by reduced response time. We investigated practice-induced changes in PPC visuomotor processing during a Go/NoGo task in humans using 306-channel magnetoencephalography. Eleven healthy adult males were instructed to extend the right index finger when presented with the Go stimulus (a red circle), but not to react to the NoGo stimulus (a green circle or a red square). Magnetic fields over the visual, posterior parietal, and sensorimotor cortices were measured before and after 3 days of task practice. The first peak of the visual-evoked field (VEF) occurred at approximately 80 ms after presentation of either the Go or NoGo stimulus, while a PPC response, with latency to a peak of 175.8 +/- A 26.7 ms, occurred only after the Go stimulus. No significant change in the first peak of VEF was measured after 3 days of task practice, but there was a significant reduction in the latency to peak PPC activity (160.1 +/- A 27.6 ms) and in the time from peak PPC activity to electromyogram onset. In all participants, practice resulted in a significant reduction in reaction time. These results demonstrate that practicing a sensorimotor task induces neuroplastic changes in PPC that accelerate sensorimotor processing and reduce motor response times.

DOI

Modulation of the cortical silent period elicited by single- and paired-pulse transcranial magnetic stimulation

Sho Kojima, Hideaki Onishi, Kazuhiro Sugawara, Hikari Kirimoto, Makoto Suzuki, Hiroyuki Tamaki

BMC Neuroscience 14 ( 43 ) doi: 10.1186/1471-2202-14-43 2013.04 [Refereed]

Background: The cortical silent period (CSP) elicited by transcranial magnetic stimulation (TMS) is affected by changes in TMS intensity. Some studies have shown that CSP is shortened or prolonged by short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF), Those studies, however, used different TMS intensities to adjust the amplitude of the motor evoked potential (MEP). Therefore, it is unclear whether changes in CSP duration are induced by changes in TMS intensities or by SICI and ICF. The purpose of this study was to confirm the effects of muscle contractions and stimulus intensities on MEP amplitude and the duration of CSP induced by single-pulse TMS and to clarify the effects of SICI and ICF on CSP duration.MEP evoked by TMS was detected from the right first dorsal interosseous muscle in 15 healthy subjects. First, MEP and CSP were induced by single-pulse TMS with an intensity of 100% active motor threshold (AMT) at four muscle contraction levels [10%, 30%, 50%, and 70% electromyogram (EMG)]. Next, MEP and CSP were induced by seven TMS intensities (100%, 110%, 120%, 130%, 140%, 150%, and 160% AMT) during muscle contraction of 10% EMG. Finally, SICI and ICF were recorded at the four muscle contraction levels (0%, 10%, 30%, and 50% EMG).Results: MEP amplitudes increased with increases in muscle contraction and stimulus intensity. However, CSP duration did not differ at different muscle contraction levels and was prolonged with increases in stimulus intensity. CSP was shortened with SICI compared with CSP induced by single-pulse TMS and with ICF at all muscle contraction levels, whereas CSP duration was not significantly changed with ICF.Conclusions: We confirmed that CSP duration is affected by TMS intensity but not by the muscle contraction level. This study demonstrated that CSP is shortened with SICI, but it is not altered with ICF. These results indicate that after SICI, CSP duration is affected by the activity of inhibitory intermediate neurons that are activated by the conditioning SICI stimulus. © 2013 Kojima et al. licensee BioMed Central Ltd.

DOI PubMed

Neuromagnetic activation following active and passive finger movements

Hideaki Onishi, Kazuhiro Sugawara, Koya Yamashiro, Daisuke Sato, Makoto Suzuki, Hikari Kirimoto, Hiroyuki Tamaki, Hiroatsu Murakami, Shigeki Kameyama

Brain and Behavior 3 ( 2 ) 178 - 192 2013.03 [Refereed]

The detailed time courses of cortical activities and source localizations following passive finger movement were studied using whole-head magnetoencephalography (MEG). We recorded motor-related cortical magnetic fields following voluntary movement and somatosensory-evoked magnetic fields following passive movement (PM) in 13 volunteers. The most prominent movement-evoked magnetic field (MEF1) following active movement was obtained approximately 35.3 ± 8.4 msec after movement onset, and the equivalent current dipole (ECD) was estimated to be in the primary motor cortex (Brodmann area 4). Two peaks of MEG response associated with PM were recorded from 30 to 100 msec after movement onset. The earliest component (PM1) peaked at 36.2 ± 8.2 msec, and the second component (PM2) peaked at 86.1 ± 12.1 msec after movement onset. The peak latency and ECD localization of PM1, estimated to be in area 4, were the same as those of the most prominent MEF following active movement. ECDs of PM2 were estimated to be not only in area 4 but also in the supplementary motor area (SMA) and the posterior parietal cortex (PPC) over the hemisphere contralateral to the movement, and in the secondary somatosensory cortex (S2) of both hemispheres. The peak latency of each source activity was obtained at 54-109 msec in SMA, 64-114 msec in PPC, and 84-184 msec in the S2. Our results suggest that the magnetic waveforms at middle latency (50-100 msec) after PM are different from those after active movement and that these waveforms are generated by the activities of several cortical areas, that is, area 4 and SMA, PPC, and S2. In this study, the time courses of the activities in SMA, PPC, and S2 accompanying PM in humans were successfully recorded using MEG with a multiple dipole analysis system. © 2013 The Authors. Published by Wiley Periodicals, Inc.

DOI

同側手内筋間および利き手‐非利き手間における皮質中継時間の違い

桐本光, 田巻弘之, 鈴木誠, 菅原和広, 宮口翔太, 大山峰生, 大西秀明

日本生体磁気学会誌 26 ( 1 ) 292 - 293 2013 [Refereed]

機械的皮膚触覚刺激による求心性抑制について

大西秀明, 菅原和広, 小島翔, 田巻弘之, 相馬俊雄, 桐本光, 大山峰生, 山代幸哉, 佐藤大輔, 丸山敦夫, 村上博淳, 亀山茂樹

日本生体磁気学会誌 ( 日本生体磁気学会 ) 25 ( 1 ) 66 - 67 2012.06

二点識別課題の体性感覚誘発脳磁界

大山峰生, 大西秀明, 相馬俊雄, 菅原和広, 村上博淳, 亀山茂樹

日本生体磁気学会誌 ( 日本生体磁気学会 ) 25 ( 1 ) 194 - 195 2012.06

Muscle-afferent projection to the sensorimotor cortex after voluntary movement and motor-point stimulation: An MEG study

Hideaki Onishi, Mineo Oyama, Toshio Soma, Hikari Kirimoto, Kazuhiro Sugawara, Hiroatsu Murakami, Shigeki Kameyama

CLINICAL NEUROPHYSIOLOGY ( ELSEVIER IRELAND LTD ) 122 ( 3 ) 605 - 610 2011.03 [Refereed]

Objective: To investigate the projection of muscle afferents to the sensorimotor cortex after voluntary finger movement by using magnetoencephalography (MEG). Methods: The movement-evoked magnetic fields (MEFs) after voluntary index-finger extension were recorded by a 204-channel whole-head MEG system. Somatosensory-evoked magnetic fields (SEFs) were recorded after motor-point stimulation was applied to the right extensor indicis muscle by using a pair of wire electrodes. Results: The MEF waveforms were observed at 35.8 +/- 9.7 ms after movement onset (MEF1). The most concentrated SEFs were identified at 78.7 +/- 5.6 ms (M70), and the onset latency of M70 was 39.0 +/- 5.5 ms after motor-point stimulation. The mean locations of the equivalent current dipoles (ECDs) of MEF1 and M70 were significantly medial and superior to that of N20m elicited by median-nerve stimulation. The ECD locations and directions of both MEF1 and M70 were concordant in the axial, coronal and sagittal planes. Conclusions: MEF1 and M70 might be elicited by muscle-afferent feedback following muscle contraction. In addition, these ECDs may be located in area 4. Significance: Motor-point stimulation is a useful tool for confirming the projection of muscle-afferent feedback to the sensorimotor cortex after voluntary movement. (C) 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

DOI

Magnetic field strength properties in bone marrow during pulsed electromagnetic stimulation.

Tamaki H, Yotani K, Yuki A, Kirimoto K, Sugawara K, Onishi H

J Biomed Sci Eng ( 3 ) 1156 - 1160 2010 [Refereed]

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