随意運動 Voluntary movements
P1-1-80 手指の随意運動における運動開始前での運動意志の中断に伴う脳活動 Brain activity related to interruption of motor intention in voluntary finger movement ○福田浩士1, 樋脇治1 ○Hiroshi Fukuda1, Osamu Hiwaki1 広島市大・情報1 Grad Sch Info Sci, Hiroshima City Univ, Hiroshima1 In the human voluntary movements, motor readiness potential is observed in the electroencephalography (EEG) about 1.5 s before the onset of movement. The motor readiness potential is supposed to reflect the activity of the movement-related cortical area including the supplementary motor area (SMA), pre-motor area (PM) and primary motor area (M1) related to the preparation and planning of the voluntary movement. In the movement adapted to the unexpected occurrence, volitional inhibition of a prepared movement has to be conducted. The volitional inhibition can be occurred in the period of the motor readiness potential before the initiation of the movement. In the present study, we investigated the dynamic cortical activities accompanied with the interruption of the motor intention prior to the onset of movement. The subject was instructed to press a force sensor with the index finger of the right hand. The time to start the movement was indicated with the clock making one revolution for 4 s. The time at which the clock hand passed the 3 o'clock position was adopted as a go-signal. In the series of the trials, the stop-signal with a red LED illumination was randomly presented at 0.1, 0.2, 0.3, 0.4 or 0.5 s before the go-signal. The cerebral potentials were recorded on the subject's scalp using a 48-ch EEG system. In the go-task without the stop-signal, clear movement-related cortical potentials (MRCPs) were observed. In the nogo-task with the stop-signal, the subject achieved to stop the finger movement. The positive component distributed at the midline fronto-central scalp with the latency of 300 ms from the stop-signal was observed only in the nogo-task. The amplitude of the positive component tended to be larger as the time of the stop-signal was closer the time of the go-signal. These results suggest that the observed positive component is associated to the interruption of motor intention and revision of motor planning in the motor cortices.	P1-1-81 マウス大脳皮質の運動関連領野における錐体ニューロンからパルブアルブミン陽性インターニューロンへの入力 Local connections of excitatory neurons to parvalbumin-containing interneurons in motor-associated cortical areas of mice ○倉本恵梨子1, 日置寛之1, 金子武嗣1 ○Eriko Kuramoto1, Hiroyuki Hioki1, Takeshi Kaneko1 京大院・医・高次脳形態1 Dept Morphol Brain Sci, Kyoto Univ, Kyoto,1 Parvalbumin (PV)-containing fast-spiking neurons are the largest subpopulation of cortical GABAergic interneurons. PV neurons may serve not only as mediators of lateral, feedforward and feedback/recurrent inhibition in the cortical circuit, but also as generators of gamma rhythms. Thus, PV-producing neurons in the cortex are considered to control the activity of pyramidal neurons, and hence play a crucial role in cortical information processing. For understanding the role of PV neurons in the local cortical circuitry, it is important to reveal the inputs that drive the interneurons. In the present study, we morphologically investigated local excitatory inputs to PV neurons in the motor-associated areas, using the transgenic mice in which the dendrites and cell bodies of PV neurons were specifically labeled with dendritic membrane-targeted GFP. In cortical slices from the transgenic mice, single pyramidal neurons of layer (L) 2/3 and L5 were intracellularly labeled with biocytin. The axon fibers of biocytin-filled pyramidal neurons were visualized by the avidin-biotinylated peroxidase complex (ABC) method with diaminobenzidin and nickel (blue black). Furthermore, the input sites, i.e. the dendrites and cell bodies, of PV neurons were immunostained with the anti-GFP antibody and ABC method with tris-aminophenylmethane (red). We reconstructed the axon fibers of intracellularly stained pyramidal neurons and counted the number of appositions formed between the local axon collaterals of each pyramidal neuron and the input sites of PV neurons. The relative frequency of appositions formed by L2/3 or L5 pyramidal neurons was 13.1% (628/4759) or 8.6% (288/3366), respectively, of the entire axon varicosities. This result suggests a difference in the local excitatory control of PV neurons between L2/3 and L5 pyramidal neurons.
P1-1-82 ラットの吻側・尾側前肢運動野における運動発現と出力制御に関連したマルチニューロン活動 Neuronal ensemble activity for motor control with different forces in rat caudal and rostral forelimb areas ○齊木愛希子1,2,3, 木村梨絵2,3, 塚元葉子2,3,4, 酒井裕1,2, 礒村宜和1,2,3 ○Akiko Saiki1,2,3, Rie Kimura2,3, Yoko Fujiwara-Tsukamoto2,3,4, Yutaka Sakai1,2, Yoshikazu Isomura1,2,3 玉川大・脳情報研究科1, 玉川大・脳科学研究所2, 科学技術振興機構・CREST3, 同志社大・脳科学研究科4 Grad Sch Brain Sci, Tamagawa Univ, Tokyo1, Brain Sci Inst, Tamagawa Univ, Tokyo2, JST-CREST, Tokyo3, Grad Sch Brain Sci, Doshisha Univ, Kyoto4 Our previous study revealed that motor cortex neurons, which may be responsible for preparation, initiation or execution of a voluntary movement, often discharge synchronously within several milliseconds. However, it remains unclear how voluntary movements are functionally controlled in a force-dependent manner by synchronous spiking activity of excitatory and inhibitory neurons in different motor cortices. We therefore investigated multi-neuronal activity in the caudal and rostral forelimb areas (CFA and RFA) of the motor cortices in head-fixed rats performing a series of forelimb movement (push-hold-pull) to manipulate a lever for reward acquisition. They were required to push and hold the lever with small or large force trial by trial (different force task). We observed functional activities in relation to the lever push, hold, and pull movements in the CFA and RFA neurons, some of which showed positive or negative correlation with the force difference. Synchronous spiking was also found among these neurons, including regular-spiking (putative excitatory) and fast-spiking (inhibitory) neurons. Furthermore, we examined whether the CFA and RFA neurons represent functional activity to keep holding the lever against an "internal force" (e.g., impulsiveness) in another group of rats performing discriminative forelimb movements (pull or not pull the lever) in response to different auditory cues (Go/No-go task). We never observed any phasic activity in response to the No-go cue specifically in the CFA and RFA neurons cooperatively participate in the force-dependent control of goal-oriented voluntary movements probably through the synchronous spiking activity, and that they contribute to the execution, but not suppression, of the voluntary movements.	P1-1-83 皮質‐筋間の同期的神経活動が精密運動制御に与える影響 Oscillatory corticomuscular coupling as a regulator of motor precision ○山田淳也1, 牛山潤一1,2, 牛場潤一2,3 ○Junya Yamada1, Junichi Ushiyama1,2, Junichi Ushiba2,3 慶應大院・理・基礎理工1, 慶應大・医・リハ2, 慶應大・理・生命情報3 Grad Sch Fund Sci and Tech, Keio Univ, Kanagawa, Japan1, Dept Rehab Med, Keio Univ Sch Med, Tokyo, Japan2, Dept Biosci and Informat, Fac Sci and Tech, Keio Univ, Kanagawa, Japan3 Oscillatory neural activity of the sensorimotor cortex shows coherence with muscular activity within the 15-35Hz frequency band (β-band) during weak to moderate intensity steady contraction. Our previous study demonstrated that the magnitude of coherence between electroencephalogram (EEG) over the sensorimotor cortex and electromyogram (EMG) varies among 100 healthy young individuals, and shows a significant positive correlation with the extent of the β-band oscillation in EMG. Considering this result, it is hypothesized that the strength of corticomuscular coupling is a factor regulating the steadiness of motor output. To test this hypothesis, we recorded the EEG over the sensorimotor cortex and EMG from the tibialis anterior muscle, when the healthy subjects (n = 13, aged 20-24 yrs) performed steady dorsiflexion at 30% of maximal effort for 60s. As results, individual magnitude of EEG-EMG coherence (peak coherence) showed significant positive correlations with the coefficient of variation of force, the sum of the power spectral density of the force within β-band, and α-band (all, p<0.05). Next, we conducted further examinations to clarify the association between the β-band EMG oscillation and the α-band force fluctuation. By careful visual observations, we found that the amplitude of EMG rhythmic burst fluctuated within the task performed by the subjects with greater EEG-EMG coherence. Further, the durations of both bursts and silent-period fluctuated within 10Hz range. In such cases, characteristic α-band fluctuations were observed in the force signal. By contrast, the amplitude of EMG in the subjects with weaker EEG-EMG coherence was stable throughout the task, leading to more precise force output. These data suggest that individual magnitude of β-band corticomuscular coupling affects the force fluctuation not only at the β-band but also at the α-band, determining the motor precision for each subject.
P1-1-84 fMRIを用いたヒトの手首随意運動における内部・外部座標系の脳内表象 Neural representation of internal and external coordination in human wrist voluntary movements revealed by functional MRI ○吉村奈津江1,2, ダサーラチャールズ サヨ2, 地村弘二1,2,3, 花川隆2,4,5, 小池康晴1,3,6 ○Natsue Yoshimura1,2, Charles S DaSalla2, Koji Jimura1,2,3, Takashi Hanakawa2,4,5, Yasuharu Koike1,3,6 東京工業大学　精密工学研究所1, 国立精神・神経医療研究センター　神経研究所　疾病研究第七部2, CREST　科学技術振興機構3, 国立精神・神経医療研究センター　脳病態統合イメージングセンター　分子イメージング研究部4, PRESTO　科学技術振興機構5, 東京工業大学　ソリューション研究機構6 Precision and Intelligence Lab., Tokyo Institute of Technology, Kanagawa, Japan1, Dept. Functional Brain Research, National Inst. of Neuroscience, NCNP, Tokyo, Japan2, CREST, Japan Science and Technology Agency, Tokyo, Japan3, Dept. Molecular Imaging, Integrative Brain Imaging Center, NCNP, Tokyo, Japan4, PRESTO, Japan Science and Technology Agency, Tokyo, Japan5, Solution Science Research Lab., Tokyo Institute of Technology, Kanagawa, Japan6 Representation of internal and external coordination frames was explored by applying functional magnetic resonance imaging (fMRI) while healthy human participants performed wrist isometric movements in three different postures. Using multivariate pattern analysis (MVPA) techniques, we trained and analyzed classifiers discriminating voxel pattern information during flexion and extension movements (i.e., internal coordination frame) and upward and downward movements (i.e., external coordination frame). The classifiers analysis demonstrated that internal and external coordination frames were dissociable in motor-related areas. Furthermore, a contribution analysis revealed M1 primarily associated with internal coordination and premotor and SMA with external coordination, although all regions were associated with both frames to some degree. Since these results are compatible with existing findings using non-human primates, the current study demonstrates fMRI-based voxel pattern information analysis could provide another means comparable to neuron-level analysis.	P1-1-85 サル赤核の運動課題遂行中の神経活動 Neuronal activity in the red nucleus of a behaving monkey ○金子将也1,2, 畑中伸彦1,2, 南部篤1,2 ○Nobuya Kaneko1,2, Nobuhiko Hatanaka1,2, Atsushi Nambu1,2 生理学研究所・生体システム研究部門1, 総研大・生命科学研究科2 Div of System Neurophysiol, Natl Inst for Physiol Sci, Okazaki, Japan1, Sch of Life Sci, The Graduate Univ for Advanced Studies, Okazaki, Japan2 The red nucleus (RN) receives inputs from the cerebral cortex and the cerebellar nuclei. Cortical projections arise from the motor cortices and project somatotopically upon the cells of the RN. The RN projects to the brainstem and to the spinal cord via the rubrospinal fibers. Thus, RN is a station in an indirect corticospinal pathway and controls limb movement in the cat and monkey. It has for a long time been believed that the rubrospinal tract is rudimentary in human. However, the recent diffusion tensor imaging study revealed the substantial size of the rubrospinal tract in human. In the present study, we recorded single unit activity of the RN of a monkey during performing motor task. We implanted stimulating electrodes in the motor cortices, such as the proximal and distal forelimb regions of the primary motor cortex (MIp and MId) and the forelimb region of the supplementary motor area (SMA) and identified cortical inputs by orthodromic responses to the stimulation of these cortical areas. A total of 34 neurons were sampled and classified according to their cortical inputs: SMA, 13; MIp, 2; SMA+MIp, 4; SMA+MId, 5; SMA+MIp+MId, 10. Cortical stimulation induced both excitatory (SMA, 26; MIp, 16; MId, 15) and inhibitory (SMA, 23; MIp, 9; MId, 8) responses. Among these neurons, 15 neurons showed significant activity changes during forearm reaching-tasks with delay (excitation, 7; inhibition, 4; combination of excitation and inhibition, 4). These results have suggested that the RN plays important roles in voluntary movements with intricate neural networks.
P1-1-86 一次運動野、運動前野の皮質内微小電気刺激はリーチング運動の終点誤差を徐々に増加させる Gradual increase of the endpoint error in target-reaching induced by microstimulation of the primary motor and the premotor cortices ○井上雅仁1, 北澤茂2,3 ○Masato Inoue1, Shigeru Kitazawa2,3 順天堂大学医学部生理学第1講座1, 大阪大学大学院生命機能研究科2, 大阪大学大学院医学研究科生理学講座3 Department of Neurophysiology, Graduate School of Medicine, Juntendo University, Hongo, Bunkyo, Tokyo, Japan1, Dynamic Brain Network Laboratory, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan2, Department of Brain Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan3 We previously showed that neurons in the primary motor cortex (M1) and the premotor cortex (PM) encoded endpoint errors in arm reaching movements. We hypothesized that these neurons transmit endpoint error signals to the cerebellum by way of the parvocellular red nucleus, and contribute to the reduction of the endpoint error in subsequent trials. To test this hypothesis, electrical microstimulation was delivered to M1 and PM of two Japanese macaques at the end of the reaching movement: assuming the hypothesis, the stimuli would serve as an artificial error signal and the error would increase trial after trial. The monkeys were trained to make rapid reaching movements toward a visual target that appeared at a random location on a tangent screen. The monkeys' view of their hand and the target was blocked during reaching movement by liquid crystal shutters. The shutters were opened again when the screen was touched, allowing the monkeys to see the target and the final position of its hand for 300 ms. In each experiment, we first recorded single neuronal activity in M1 or PM, and determined the preferred direction of the error for each neuron. When the recorded neuron encoded error information, we delivered electrical microstimulation after the touch by using the same electrode. Repetitive pairing of reaching movements with microstimulation produced a gradual increase of the endpoint error over 20-30 trials, in the direction opposite to the preferred error direction of the recorded neuron. The results support our hypothesis that neurons in M1 and PM transmit error signals after each movement, and contribute to the reduction of the error in subsequent trials.	P1-1-87 能動的注意が両手運動の協調性に与える影響 Effect of top-down attention during bimanual movements ○櫻田武1, 神作憲司1 ○Takeshi Sakurada1, Kenji Kansaku1 国リハ研究所・脳機能・脳神経科学1 Sys Neurosci Sect, Dept of Rehab for Brain Func, Res Inst of NRCD, Tokorozawa, Japan1 It has been suggested that instructions including external focus of attention are effective in motor skill learning and performance (Wolf et al. 2010); however, spatial dependence of this phenomenon is not well known. In this study, we investigated spatial dependence of top-down attention during bimanual symmetrical movements.Fifteen right-handed participants performed bimanual reaching movements. During the movements, hand-cursors representing the positions of bilateral hands and an object-cursor were displayed on a LCD monitor. The participants were required to carry the object-cursor by the hand-cursors. The participants were instructed to control direction of top-down attention (left side, right side, or both sides) during performing the movements. The participants performed the constant movements (7 cm) in normal trials. In catch trials, we modified visuomotor gain (visual perturbation) and the participants were required to perform movements in large amplitude (14 cm) in one hand. The amplitude of the opposite hand was affected in the catch trials, and we evaluated the unintentional motor interference as the degree of bimanual coupling.Here we showed that effect of top-down attention has spatial dependence during bimanual symmetrical movements; i.e., when the participants direct their attention to the left side or both sides of space, the coupling strength significantly increased compared with that to the right side of space (p<0.05, corrected).The results suggested that bimanual symmetrical movements are affected by spatial location of external focus of attention, and the right parietal cortex could be a key region to further understand its underlying mechanisms.
P1-1-88 外発性・内発性運動に伴うラット一次・二次運動野の協調的神経活動 Cooperative multineuronal spike activities related to externally- and internally-initiated movements in rat primary and secondary motor cortices ○木村梨絵1,2, 齊木愛希子1,2,3, 塚元葉子1,2,4, 酒井裕1,3, 礒村宜和1,2,3 ○Rie Kimura1,2, Akiko Saiki1,2,3, Yoko Fujiwara-Tsukamoto1,2,4, Yutaka Sakai1,3, Yoshikazu Isomura1,2,3 玉川大・脳科学研究所1, 科学技術振興機構・CREST2, 玉川大・脳情報研究科3, 同志社大・脳科学研究科4 Brain Sci Inst, Tamagawa Univ, Tokyo1, JST-CREST, Tokyo2, Grad Sch Brain Sci, Tamagawa Univ, Tokyo3, Grad Sch Brain Sci, Doshisha Univ, Kyoto4 Our previous study reported that many neurons of motor cortex of rats, which may be responsible for motor preparation, initiation, and execution, often discharge synchronously within several milliseconds. However, it remains to be determined how such neuronal activities are expressed depending on different types of motor initiation, i.e., by an external signal such as auditory cues or by an internal signal originating from their own brain state. It also remains unclear whether they have functional similarities or differences among different motor cortical areas. Here, we examined neuronal activities and their local synchronization in the primary and secondary motor cortices (M1 and M2) of rats performing an operant behavioral task under a head-fixed condition. The operant behavioral task required the rats to pull a lever using their forelimb in response to a cue tone (externally-initiated movement trials) or pull it spontaneously without the cue (internally-initiated movement trials) after waiting for at least one second. The rats learned to perform total 1000-1500 success trials for three hours after three training days. By our multi-neuronal and juxtacellular recordings from the forelimb area of M1 or M2, we found some of regular-spiking and fast-spiking neurons in the M1 and M2 fired differentially between the externally- and internally-initiated movements. Furthermore, we confirmed that spike coincidence occurred among functionally similar or different neurons in M1 and M2, and that some of those pairs showed spike coincidence in a task-situation-dependent manner. Our results suggest that the individual neuronal activities and their spike coincidence play a functional role in cooperative motor control in these two motor cortices.	P1-1-89 把握運動制御における大脳皮質および脊髄神経機構の機能的差異 Contrasting roles of spinal and cortical premotor neurons for a control of grasping ○武井智彦1,2, 関和彦1,2,3 ○Tomohiko Takei1,2, Kazuhiko Seki1,2,3 国立精神・神経セ神経研モデル動物開発1, 生理研発達生理認知行動発達2, JSTさきがけ3 Dept of Neurophysiol, Natl Inst of Neurosci, Tokyo1, Dept of Developmental Physiol, Natl Inst for Physiological Sci, Okazaki2, PRESTO, JST, Tokyo3 Corticomotoneuronal (CM) cells and spinal premotor interneurons (PreM-INs) are major input sources of hand motoneurons but their relative roles for a control of hand movements remained to be unraveled. Here we explored it by examining their post-spike effects (PSEs) on hand muscle activities and by comparing their firing activities during voluntary hand movements. Three macaque monkeys were trained to grip and hold two spring-loaded levers with their index finger and thumb (precision grip task). Single-unit activities were recorded in spinal cord (C6 - T1) or primary motor cortex (M1) while monkeys performing the task, simultaneously with electromyographyic signals (EMGs) from 20 hand and arm muscles. Spike-triggered averaging of rectified EMGs revealed that 23 spinal and 21 cortical neurons produced PSEs on at least one muscle, and they were identified PreM-INs and CM cells. A majority of PreM-INs (15/23, 65%) produced PSEs on more than one muscle, and the number of muscles which showing PSEs (muscle field: MF) was 2.7 ± 2.1 (mean ± SD). In contrast, a smaller proportion of CM cells showed such a divergent muscle field (9/21, 43%) and the MF size was smaller than those of PreM-IN (1.8 ± 1.0). Characteristics of their firing pattern were also contrasting. Most of PreM-INs (10/23, 43%) showed both of phasic facilitation at grip period and tonic facilitation during hold period (p+t+ pattern), which was consistent to that most of EMGs also showed the p+t+ pattern. On the other hand, the CM cells showed pure phasic (p+) and phasic facilitation with tonic suppression (p+t-) equally to the p+t+ pattern (p+t+: 22%, p+: 26%, p+t-: 22%). These results suggested the contrasting functions of the two systems for a control of hand movements: PreM-INs function to construct a basic profiles of hand muscle activity, with a larger MF and "muscle-like" activity, on which CM cells add a finer tuning on specific muscles, with their narrower MF and divergent activity patterns.

上部に戻る

前に戻る