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It is still unclear how rehabilitative intervention assists recovery from strokes. In order to address this question, we made an animal model to examine the recovery process after experimental strokes. The forelimb movements in 2 monkeys retrieving food from a well were analyzed with a videotape recording. A small infarction by coagulation of blood vessels was made in the forelimb areas after mapping of the primary motor areas. The recovery process was evaluated by measuring the time required for taking food. We used the modified Kluver board with the small diameter in order to restrict the monkeys' compensatory movements such as pronation or supination. After the infarction, the monkeys could not use their impaired hands for the first 2 days. Failure to retrieve food and compensatory movements such as involvement of other joints were often observed during the first week. However, the forelimb function of both monkeys showed no significant impairments on the 6th week, compared to the results before the infarction. Throughout the experiments, the monkeys showed no supination or pronation of the forearm. These results suggest that this animal model with the modified Kluver board may be useful for the evaluation of motor deficit.

The smooth-pursuit system moves the eyes in space accurately to track slowly moving objects of interest despite visual inputs from the moving background and/or vestibular inputs during head movements. Recently, our laboratory has shown that young primates exhibit asymmetric eye movements during vertical pursuit across a textured background; upward eye velocity gain is reduced. To further understand the nature of this asymmetry, we performed three series of experiments in young monkeys. In Experiment 1, we examined whether this asymmetry was due to an un-compensated downward optokinetic reflex induced by the textured background as it moves across the retina in the opposite direction of the pursuit eye movements. For this, we examined the monkeys’ ability to fixate a stationary spot in space during movement of the textured background and compared it with vertical pursuit across the stationary textured background. We also examined gains of optokinetic eye movements induced by downward motion of the textured background during upward pursuit. In both task conditions, gains of downward eye velocity induced by the textured background were too small to explain reduced upward eye velocity gains. In Experiment 2, we examined whether the frame of reference for low-velocity, upward pursuit was orbital or earth vertical. To test this, we first applied static tilt in the roll plane until the animals were nearly positioned on their side in order to dissociate vertical or horizontal eye movements in the orbit from those in space. Deficits were observed for upward pursuit in the orbit but not in space. In Experiment 3, we tested whether asymmetry was observed during head-free pursuit that requires coordination between eye and head movements. Asymmetry in vertical eye velocity gains was still observed during head-free pursuit although it was not observed in vertical head velocity. These results, taken together, suggest that the asymmetric eye movements during vertical pursuit are specific for upward, primarily eye pursuit in the orbit.

The ERG (Exploration of energization and Radiation in Geospace) is Japanese geospace exploration project. The project focuses on relativistic electron acceleration mechanism of the outer belt and dynamics of space storms in the context of the cross-energy coupling via wave-particle interactions. The project consists of the satellite observation team, the ground-based network observation team, and integrated-data analysis/simulation team. The satellite was launched on December 20 2016 and has been nicknamed, "Arase". This paper describes overview of the project and future plan for observations.

Wave Particle Interaction Analyzer (WPIA) is onboard software to be installed in the upcoming JAXA/ERG satellite. The significance of the WPIA is studied for measurement of the energy transfer process directly between energetic electrons and whistler-mode chorus emissions in the Earth's inner magnetosphere. The WPIA measures a relative phase angle between the wave electromagnetic field vector (E or B) and velocity vector (v) of each electron and computes physical quantities such as an inner product W, where W is the inner product between v and E and is the time variation of the kinetic energy of energetic electrons interacting with plasma waves. This paper presents the feasibility of the WPIA, which is evaluated by applying the analysis to simulation results of whistler-mode chorus generation.

Anticipatory postural adjustments (APAs) provide postural stability and play an important role in ensuring appropriate motor performance. APAs also change in various situations. However, it is unknown whether changes in APAs during repetitive movement training contribute to improvement in motor performance. This study aimed to investigate the relationship between improvement in motor performance and changes in APAs during repeated reaching training, as well as the learning effects on APA changes. Sixteen healthy subjects (23 +/- 2 years of age) stood barefoot on a force platform and reached as quickly and accurately as possible to a target placed at their maximum reach distance immediately following a beep signal in a reaction time condition. Whole-body reaching training with the right arm was repeated 100 times for three consecutive days. Motor performance and APAs were evaluated on the first day, after discontinuation of training for one day, and again at three months. In addition, reaching with the left arm (untrained limb) was tested on the first and the fifth training day. Body position segments were measured using three-dimensional motion analysis. Surface electromyography of eight postural muscles in both lower limbs was recorded. Kinetics data were recorded using the force platform. Whole-body reaching training induced not only improvements in motor performance (e.g., increased peak hand velocity), but also changes in APAs (e.g., earlier APA onset and increased amplitude). These changes were strongly correlated with and occurred earlier than improvements in motor performance. The learning effects on APAs were retained after the discontinuation of training and were generalized to the untrained limb. These results suggest that change in APAs contributes to improvement in motor performance; that is, the central nervous system may be able to adapt APAs for improvement in motor performance. (c) 2014 The Authors. Published by Elsevier B.V.

In order to explore the electron distribution of hydrogen, an electron density study was carried out by maximum entropy method (MEM) using the single crystal X-ray diffraction data of LiH measured by Vidal-Valat et al. [Acta Crystallogr. A48 (1992) 46–60] and those of LiOH measured by Gottlicher and Kieselbach [Acta Crystallogr. A32 (1976) 185–192]. It was found that the electron distribution of hydrogen in LiH is very spherical as a consequence of high symmetrical crystalline field. It was also recognized that there exists very weak covalent bond between lithium and hydrogen along the 〈100〉 direction. These features were consistent with the results of difference Fourier synthesis and multipole analysis by Vidal-Valat et al. Contrary to the LiH case, the position of hydrogen in LiOH was hardly assigned from the electron density map and only the contribution of hydrogen was recognized as a distortion of electron clouds of OH ellipse. The present study demonstrated that the electron distribution of hydrogen can be detected by MEM but it should be kept in mind that the distribution of electron from hydrogen was severely affected by the crystal field, which may result in the fact that the electron from hydrogen is far from a spherical distribution.

The Energization and Radiation in Geospace (ERG) project for solar cycle 24 will explore how relativistic electrons in the radiation belts are generated during space storms. This geospace exploration project consists of three research teams: the ERG satellite observation team, the ground-based network observation team, and the integrated data analysis/simulation team. Satellite observation will provide in situ measurements of features such as the plasma distribution function, electric and magnetic fields, and plasma waves, whereas remote sensing by ground-based observations using, for example, HF radars, magnetometers, optical instruments, and radio wave receivers will provide the global state of the geospace. Various kinds of data will be integrated and compared with numerical simulations for quantitative understanding. Such a synergetic approach is essential for comprehensive understanding of relativistic electron generation/loss processes through crossenergy and cross-regional coupling in which different plasma populations and regions are dynamically coupled with each other. In addition, the ERG satellite will utilize a new and innovative measurement technique for wave-particle interactions that can directly measure the energy exchange process between particles and plasma waves. In this paper, we briefly review some of the profound problems regarding relativistic electron accelerations and losses that will be solved by the ERG project, and we provide an overview of the project.

著者人数: 11名, 資料番号: SA1160221000

[1] Planetary auroral emissions reveal the configuration of magnetospheric field-aligned current systems. In this study, Cassini Visual and Infrared Mapping Spectrometer (VIMS) observations of Saturn's pre-equinox infrared H3+ aurorae were analysed to show (a) rotational modulation of the auroral intensity in both hemispheres and (b) a significant local time dependence of the emitted intensity. The emission intensity is modulated by the ‘planetary period’ rotation of auroral current systems in each hemisphere. The northern auroral intensity also displays a lesser anti-phase dependence on the southern rotating current system, indicating that part of the southern current system closes in the northern hemisphere. The southern hemisphere aurorae were most intense in the post-dawn sector, in agreement with some past measurements of auroral field-aligned currents, UV aurora and SKR emitted power. A corresponding investigation of the northern hemisphere auroral intensity reveals a broader dawn-noon enhancement, possibly due to the interaction of the southern rotating current system with that of the north. The auroral intensity was reduced around dusk and post-midnight in both hemispheres. These observations can be explained by the interaction of a rotating field-aligned current system in each hemisphere with one fixed in local time, which is related to the solar wind interaction with magnetospheric field lines.

We present Cassini Visual and Infrared Mapping Spectrometer observations of infrared auroral emissions from the noon sector of Saturn's ionosphere revealing multiple intense auroral arcs separated by dark regions poleward of the main oval. The arcs are interpreted as the ionospheric signatures of bursts of reconnection occurring at the dayside magnetopause. The auroral arcs were associated with upward field-aligned currents, the magnetic signatures of which were detected by Cassini at high planetary latitudes. Magnetic field and particle observations in the adjacent downward current regions showed upward bursts of 100–360 keV light ions in addition to energetic (hundreds of keV) electrons, which may have been scattered from upward accelerated beams carrying the downward currents. Broadband, upward propagating whistler waves were detected simultaneously with the ion beams. The acceleration of the light ions from low altitudes is attributed to wave-particle interactions in the downward current regions. Energetic (600 keV) oxygen ions were also detected, suggesting the presence of ambient oxygen at altitudes within the acceleration region. These simultaneous in situ and remote observations reveal the highly energetic magnetospheric dynamics driving some of Saturn's unusual auroral features. This is the first in situ identification of transient reconnection events at regions magnetically conjugate to Saturn's magnetopause.

Magnetic reconnection in planetary magnetospheres plays important roles in energy and mass transfer in the steady state, and also possibly in transient large-scale disturbances. In this paper we report observations of a reconnection event in the Jovian magnetotail by the Galileo spacecraft on 17 June 1997. In addition to the tailward retreat of a main X-line, signatures of recurrent X-line formations are found by close examination of energetic particle anisotropies. Furthermore, detailed analyses of multi-instrumental data for this period provide various spatiotemporal features in the plasma sheet. A significant density decrease was detected in the central plasma sheet, indicative of the transition to lobe (open field line) reconnection from plasma sheet (closed field line) reconnection. When Galileo vertically swept through the plasma sheet, a velocity layer structure was observed. We also analyze a strong southward magnetic field which is similar to dipolarization fronts observed in the terrestrial magnetotail: the ion flow (∼450 km s−1) was observed behind the magnetic front, whose thickness of 10000–20000 km was of the order of ion inertial length. The electron anisotropy in this period suggests an anomalously high-speed electron jet, implying ion-electron decoupling behind the magnetic front. Particle energization was also seen associated with these structures. These observations suggest that X-line evolution and consequent plasma sheet structures are similar to those in the terrestrial magnetosphere, whereas their generality in the Jovian magnetosphere and influence on the magnetospheric/ionospheric dynamics including transient auroral events need to be further investigated with more events.

Introduction: Rugby is one of the most tactically complex sports. Rugby coaching theory suggests that rugby players need to possess various cognitive abilities. A previous study claimed that rugby players have high visuospatial awareness, which is induced by a strategy described as taking a "bird's eye view." Methods: To examine if there were differential cortical networks related to visuospatial processing tasks among top-level rugby players and control novices, we compared brain activities during a visuospatial processing task between 20 male top-level rugby players (Top) and 20 control novice males (Novice) using functional magnetic resonance imaging (fMRI). To avoid the effect of differential behavioral performances on brain activation, we recruited novices whose visuospatial ability was expected to match that of the rugby players. We adopted a 3-D mental rotation task during fMRI scanning as a visuospatial processing task. Results: Significantly greater activations from baseline were observed for the Top group than for the Novice group in the right superior parietal lobe and lateral occipital cortex. Significantly greater deactivations from baseline were observed for the Top group than for the Novice group in the right medial prefrontal cortex. Conclusions: The discrepancy between psychobehavioral outputs and the fMRI results suggested the existence of a cognitive strategy among top-level rugby players that differs from that among control novices. The greater activation of the right superior parietal lobe and lateral occipital cortex in top-level rugby players suggested a strategy involving visuospatial cognitive processing with respect to the bird's eye view. In addition, the right medial prefrontal cortex is known to be a part of the default mode networks, suggesting an additional cognitive load for the Top group when using the bird's-eye-view strategy. This further supported the existence of a specific cognitive strategy among top-level rugby players.

To the Editor: The role played by the brain's dopamine system in pain control has garnered attention in recent years.1 Herein, we report 4 cases of long-term chronic pain (pain disorder [DSM-IV-TR]) that improved dramatically following administration of a low dose of aripiprazole, a partial dopamine agonist. None of these 4 patients satisfied the DSM-IV-TR diagnostic criteria for schizophrenia. Case 1. Mr A, a 42-year-old man, had a chief complaint of chronic head and neck pain that had persisted for 10 years and was refractory to administration of morphine 70 mg/d. He visited our department in December 2008 and was diagnosed with pain disorder and pervasive developmental disorder. Although fluvoxamine treatment was started, with the dosage gradually increased to 200 mg/d, it was ineffective and the pain exacerbated. Upon switching to aripiprazole 3 mg/d, the pain improved dramatically, and the patient was able to discontinue morphine. After increasing the dose to 6 mg/d, the patient became able to go fishing for the first time in a few years, and his motivation increased. Case 2. Mr B, a 35-year-old man, had chronic back and leg pain that had persisted for 15 years and particularly worsened following sexual intercourse. He had visited over 20 medical institutions in the past and had not responded to antidepressants. He visited our department in March 2009 and was diagnosed with pain disorder. Pain disappeared after initiation of aripiprazole 2 mg/d, and the patient's passion for his work in computer software development improved. As aripiprazole was effective in the treatment of pain disorder in Cases 1 and 2, we subsequently also used it for Cases 3 and 4, and it was effective. Below are concise descriptions of Cases 3 and 4. Case 3. Ms C, an 83-year-old woman, had developed Parkinson's disease and back and leg pain (pain disorder) 4 years before. She visited our department in August 2009. Pain improved following administration of aripiprazole 3 mg/d, and the patient began going out rather than staying home as she had been, and her level of activity improved. Case 4. Ms D, a 68-year-old woman, had developed pain at the top of the head (pain disorder) a year before she visited our department in October 2009. Pain disappeared after we added aripiprazole 2 mg/d to sertraline 100 mg/d, and the patient's motivation toward housework improved. These 4 patients were characterized by reduction of pain and improved motivation following low-dose aripiprazole administration. Dopamine plays a role in pain processing via μ opioids.1 Dopamine-related diseases often exhibit pain-related symptoms. For example, pain is a common complaint among patients with Parkinson's disease,2 and those with schizophrenia are known to have a reduced pain sensitivity.3 In other words, the degree of dopamine system activation is inversely proportional to the degree of pain. These 4 cases suggest that aripiprazole, a dopamine system stabilizer, may be a therapeutic option for chronic pain.

The smooth-pursuit system is important to precisely track a slowly moving object and maintain its image on the foveae during movement. During whole-body rotation, the smooth-pursuit system interacts with the vestibular system. The caudal part of the frontal eye fields (FEF) contains smooth pursuit-related neurons that signal eye velocity during pursuit. The majority of them receives vestibular inputs and signal gaze-velocity during passive whole-body rotation. It was asked whether discharge modulation of FEF pursuit neurons during head rotation on the stationary trunk could be accounted for by vestibular inputs only or if both vestibular and neck proprioceptive inputs contributed to the modulation. Discharge modulation during active head pursuit, passive head rotation on the stationary trunk, passive whole-body rotation, and passive trunk rotation against the stationary head were compared. The results indicate that both vestibular and neck proprioceptive inputs contributed to the discharge modulation of FEF pursuit neurons during head movements.

became observable in the energy window of Polar were transported from the high-latitude magnetopause to the inner magnetosphere when the convection electric field was strong. When the convection electric field was weak, the ions were reflected toward the distant tail. The O 6+ ions that became observable in the energy window of Geotail were sufficiently transported from the low-latitude magnetopause to the near-Earth magnetotail regardless of the strength of the convection electric field. The observational facts may be adequately explained in terms of ion transport paths depending on the convection electric field with different entry points.

[1] We study the acceleration of energetic electrons during magnetotail reconnection by using Cluster simultaneous measurements of three-dimensional electron distribution functions, electric and magnetic fields, and waves in a thin current sheet. We present observations of two consecutive current sheet crossings where the flux of electrons 35–127 keV peaks within an interval of tailward flows. The first crossing shows the signatures of a tailward moving flux rope. The observed magnetic field and density indicate that the flux rope was very dynamic, and a comparison with numerical simulation suggests a crossing right after coalescence of smaller flux ropes. The second crossing occurs within the ion diffusion region. The flux of electrons is largest within the flux rope where they are mainly directed perpendicular to the magnetic field. At the magnetic separatrices, the fluxes are smaller, but the energy spectra are harder and electrons are mainly field aligned. Reconnection electric fields EY ∼ 7 mV/m are observed within the diffusion region, whereas in the flux rope, EY are much smaller. Waves around lower hybrid frequency do not show a clear correlation with energetic electrons. We interpret the field-aligned electrons at the separatrices as directly accelerated by the reconnection electric field in the diffusion region, whereas we interpret the perpendicular electrons as trapped within the flux rope and accelerated by a combination of betatron acceleration with nonadiabatic pitch-angle scattering. Our observations indicate that thin current sheets during dynamic reconnection are important for in situ production of energetic electrons and that simultaneous measurements of electrons and electromagnetic fields within thin sheets are crucial to understand the acceleration mechanisms.

This study assessed the relationship of each movement direction on the lumbar spine and on the pelvis in regards to lumbar-pelvic coordination in the sitting position. Lumbar and pelvic motions were recorded using a flexible electrogoniometer in 12 healthy subjects during two different tasks in the sitting position. The coordination of the lumbar spine and pelvis was evaluated using the ratio of lumbar and pelvic angles (L/P ratio hereafter) in three motion phases. There were significant differences in the L/P ratio values between during the "forward bending" and "rising from a forward flexed position" phases (P0.01). The L/P ratio value ( approximately -0.7) was consistent during the movement from an erect to a slumped sitting position as the lumbar spine and pelvis moved in opposing directions. This study shows that lumbar-pelvic coordination occurs in the sitting position. Lumbar-pelvic coordination is confirmed even if the movement tasks are different in the sitting position, and these findings show that aspects of a particular movement are dependent on the given movement task. These findings may provide greater insight into the kinematic changes involved in lumber-pelvic coordination, and help clinicians implement sitting exercises conducive to the independence of the patient.

Background: A reaching movement is an important action in daily life. When a reaching movement is directed to a target placed at a distance greater than arm length in standing, a driving or braking force must be created to initiate and to terminate whole body movement (Tyler and Karst, 2004). Therefore, the central nervous system activates postural muscles at an appropriate timing and subsequent initiates joint motion in lower limb. Though it is well known that motor components such as the peak velocity of arm movements improve through reaching training, it remains unclear how postural components improve. Purpose: The repeated reaching training is widely adopted as one of rehabilitation programs on a clinical treatment. However, changes in postural control during reaching training have been rarely reported. Therefore, the purpose of this study is to investigate change in muscle activity and joint angle of lower limbs through repeated reaching training in standing posture. Methods: Fifteen healthy subjects (23± 2 years) participated. All subjects provided written informed consent, as approved by the ethics committee of Hokkaido University Faculty of Health Sciences. Subjects performed reaching to a small target placed in the nearly maximum reach distance as quickly as possible. One hundred trials of reaching with right arm were repeated for three consecutive days and they were examined again after discontinuing training for one day. The surface electromyography (EMG) of tibialis anterior (TA) and gastrocnemius (GAS) was recorded. Kinematic data were collected using a three-dimensional motion analysis system. The integrated EMG (IEMG) were calculated for driving phase (from the reaching onset to the time when hand velocity was maximal) and braking phase (from the time when hand velocity was maximal to termination time of reaching). Hip, knee, and ankle joint angles were calculated. Mean value of the parameters in the first 10 trials on the first training day were compared with those of the other 10 trials on the first training day, and with those of the first 10 trials on the other training day using one-way repeated measure ANOVA and a post-hoc test. The significance level was set at p< 0.05. Results: On the first day, the normalized IEMG of the right TA in driving phase (p< 0.01) and the left GAS in braking phase (p< 0.01) significantly increased through repeated reaching training. Also, the maximum ankle dorsiflexion angle in driving phase (p< 0.05) and the maximum hip flexion angle in braking phase (p< 0.05) significantly increased. Training effects on these parameters were retained after a two-day rest period. Conclusion(s):We found that changes in postural control occurred in both driving and braking phase during a repetitive reaching task. Training effects were retained after subjects discontinued training. These results suggest postural learning not only to initiate thewhole body forwardmovement but also to terminate the movement occur during a repetitive reaching task. Implications:A better understanding of the postural control mechanism during repetitive reaching training is useful for physical therapy practices.

Accepted: 2006-11-14, 資料番号: SA1000457000

Following the end of the Van Allen Probes mission, the Arase satellite offers a unique opportunity to continue in-situ radiation belt and ring current particle measurements into the next solar cycle. In this study we compare spin-averaged flux measurements from the MEPe, HEP-L, HEP-H, and XEP-SSD instruments on Arase with those from the MagEIS and REPT instruments on the Van Allen Probes, calculating Pearson correlation coefficient and the mean ratio of fluxes at L* conjunctions between the spacecraft. Arase and Van Allen Probes measurements show a close agreement over a wide range of energies, observing a similar general evolution of electron flux, as well as average, peak, and minimum values. Measurements from the two missions agree especially well in the 3.6 ≤ L* ≤ 4.4 range where Arase samples similar magnetic latitudes to Van Allen Probes. Arase tends to record higher flux for energies < 670 keV with longer decay times after flux enhancements, particularly for L* < 3.6 . Conversely, for energies > 1.4 MeV, Arase flux measurements are generally lower than those of Van Allen Probes, especially for L* > 4.4 . The correlation coefficient values show that the > 1.4 MeV flux from both missions are well correlated, indicating a similar general evolution, although flux magnitudes differ. We perform a preliminary intercalibration between the two missions using the mean ratio of the fluxes as an energy- and L*- dependent intercalibration factor. The intercalibration factor improves agreement between the fluxes in the 0.58-1 MeV range.