姿勢と歩行 Posture and Gait
P1-1-75 ヒト腰随に存在する歩行に関わるNeural module Neural modules for walking in human lumbar spinal cord ○笹田周作1, 加藤健治1,2,3, 門脇傑4, 宇川義一4, 小宮山伴与志5, 西村幸男1,6 ○Syusaku Sasada1, Kenji Kato1,2,3, Suguru Kadowaki4, Yoshikazu Ugawa4, Tomoyoshi Komiyama5, Yukio Nishimura1,6 自然科学研究機構　生理学研究所　発達生理学研究系　認知行動発達機構研究部門1, 総合研究大学院大学・生命科学研究科2, 日本学術振興会・特別研究員3, 福島県立医科大学・医学部・神経内科学講座4, 千葉大学・教育学部5, 科学技術支援機構・さきがけ6 Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Japan1, Life Science, The Graduate University for Advanced Studies, Okazaki, Japan2, The Japan Society for the Promotion of Science, Tokyo, Japan3, Department of Neurology, Fukushima Medical University, Fukushima, Japan4, Faculty of Education, Chiba University, Chiba, Japan5, PRESTO, Japan Science and Technology Agency, Tokyo, Japan6 Coordinated pattern of leg movements is produced by locomotor network in lumbar spinal cord during walking. It is, however, unclear how the network formulates coordinated, alternating movement pattern between right and left legs. We have reported that the volitionally-controlled non-invasive magnetic burst stimulus over the lumbar spinal cord induced the walking behavior in legs in intact participants. The behavior may be partly or entirely produced by a neural module which controls a group of muscles for walking. To tackle this issue, we investigate how the behavioral pattern depends on the stimulation site on lumbar spinal nerves. Subjects (healthy volunteers, n = 8) lie down with semi-prone position and an arm and legs was hooked up by wires respectively. The midline of each inter-vertebra on lumbar spine was stimulated by voluntarily-controlled magnetic stimulation. We investigate location specific change of behavioral pattern induced by the stimulation. Right-left alternating walking behavior was induced in legs during the volitionally-controlled magnetic burst stimulation in 6 of 8 subjects. The behavior was most frequently and powerfully induced when the stimulus probe was positioned at the L2-L3 intervertebral segment, and it was less frequently induced when the stimulus site was positioned on rostral or caudal to that segment. In these 4 of 6 subjects, the forward step was induced on the ipsilateral leg to the stimulation site, whereas the backward step was induced in contralateral leg to the stimulation site. This mirror-like oppositely directed behavioral pattern depending on the stimulation side indicates that two distinct neural modules locate on left and right side. They may mutually interact with each other and formulate alternating movement pattern between right and left legs. These neural modules might be a part of locomotor network for walking.	P1-1-76 cbln1-null miceにおける歩行失調の動作学的解析 Kinematic analysis of ataxic gait in cbln1-null mice ○竹内絵理1,2, 石田綾3,4, 山浦洋1, 柚崎通介4,5, 加藤明2, 柳原大1,5 ○Eri Takeuchi1,2, Aya Ito-Ishida3,4, Hiroshi Yamaura1, Michisuke Yuzaki4,5, Akira Katoh2, Dai Yanagihara1,5 東京大院・総合文化1, 東海大・創造科学技術研究機構2, ベイラー医科大 分子人類遺伝学3, 慶應大・医・生理学4, 科学技術振興機構　CREST5 Grad Sch Arts and Sci, Univ of Tokyo, Tokyo, Japan1, IIST, Tokai Univ, Kanagawa, Japan2, Dept of Mol and Hum Genet, Baylor Coll of Med, Houston, USA3, Dept Physiolo, Sch of Med, Keio Univ, Tokyo, Japan4, JST, CREST, Tokyo, Japan5 The patients with cerebellar damage display ataxic gait characterized by impaired coordination of limb movements. Recently, we reported characteristics of ataxic gait in ho15J mice that have a Jmutation of the δ2 glutamate receptor. Analysis of hindlimb kinematics during treadmill locomotion showed abnormal movements characterized by excessive toe elevation during the swing phase, and by severe hyperflexion of the ankles in ho15J mice. Here, gait ataxia in cbln1-null mice was investigated by kinematic analysis of hindlimb movements during treadmill locomotion. Cbln1 is predominately expressed and secreted from cerebellar granule cells, the cerebellum of the cbln1-null mice is characterized by a 60% reduction in the number of parallel fiber-Purkinje cell synapses compared with wild-type mice. There were prominent differences in temporal parameters of locomotion between the cbln1-null and wild-type mice. In the cbln1-null mice, abnormal hindlimb movements were characterized by excessive toe elevation during the swing phase, and by severe hyperflexion of the ankles and knees. Moreover, application of recombinant Cbln1 to the cerebellum, step cycle and stance phase durations were increased toward those of wild-type mice, and the angular excursions of the knee during a cycle period showed a much closer agreement with that of the wild-type mice. During locomotion, the vermis and intermediate region of the cerebellum receive information originating from the spinal stepping generator or peripheral somatosensory receptors through the spinocerebellar pathways. These findings suggest that dysfunction of the parallel fiber-Purkinje cell synapses might underlie the impairment of hindlimb movements during locomotion in cbln1-null mice.
P1-1-77 重錘落下課題において予測可能な外乱が繰り返し与えられたときの姿勢の適応 Postural adaptation to the predictable repeated perturbation during a load release task ○齊藤展士1, 山中正紀1, 笠原敏史1 ○Hiroshi Saito1, Masanori Yamanaka1, Satoshi Kasahara1 北海道大学大学院　保健科学研究院　機能回復学分野1 Department of Rehabilitation Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan1 The central nervous system controls postural muscles in three different phases to maintain postural stability. The time course on postural control is divided into three phases, such as anticipatory phase (-100 to 50 ms), automatic phase (50 to 200 ms), and voluntary phase (200 to 350 ms) from the focal movement onset (Latash 2008). It is known that postural responses to repeated sinusoidal support surface perturbation adapt clearly after a few cycles. However, it is unclear in which phase postural adaptation is induced. We examined whether postural adaptation in lower limb muscles is induced by the predictable repeated perturbation during a load release task, and if so, in which phase the postural adaptation was induced. Ten healthy subjects (21 ± 1 years) were required to stand, holding a load bar (3 % body weight) with both hands at shoulder level, and to release it 10 times (pretest). In adaptation test, external predictable perturbation force (6 % body weight) was applied to trunk for bending forward simultaneously with load release, which was repeated 50 times. Then, posttest similar to the pretest was repeated 20 times. The surface electromyograms (EMG) of tibialis anterior (TA), gastrocnemius (GAS), rectus femoris (RF), and biceps femoris (BF) were recorded. The integrated EMG was calculated in each phase. The infrared cameras measured displacement of the head. In pretest, robust inhibitions of activity in GAS and BF were observed. During the last ten trials in adaptation test, the inhibitions were significantly decreased. The changes in postural muscle responses were observed clearly in anticipatory phase. In addition, the backward displacement of the head significantly increased and occurred earlier. After ten trials in posttest, robust inhibitions of muscle activities recovered again. These results suggest that the predictable repeated perturbation induces postural adaptation in anticipatory phase and the adapted postural responses could recover rapidly.

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