体性感覚 Somatosensory System
P2-2-119 体性感覚入力の消失に伴って棒をもった実験的幻肢は動く An experimental phantom hand with a pole moves during ischemic anesthesia ○乾信之1 ○Nobuyuki Inui1 鳴門教育大院・学校教育・保健体育1 Grad. Sch. Edu. Naruto Univ. Edu., Naruto1 Our previous studies (J. Physiol. 2011, Exp. Brain Res. 2012) showed that a fully flexed or extended finger, wrist, and elbow became perceived as an extended or flexed 'phantom' hand and arm as ischemic anesthesia progressed. Here, the present study examined what happened if a pole was fixed to an experimental phantom hand while the fully extended wrist and elbow were perceived to flex during the anesthesia (40 min). Ten healthy participants lay comfortably on their back on a bed with their eyes closed and a pole was fixed to their right hand by a triangle bandage. The participants demonstrated the perceived postures of their right wrist and elbow during an ischemic block of the right upper arm with the left hand and arm. In addition, they reported whether they felt that they had a pole with their hand during the block or not. Surprisingly, a pole fixed to the hand was perceived to move towards flexion with the phantom hand from 10 to 20 min after the block while the perceived position of the wrist and elbow moved towards flexion from 10 to 40 min after the block. While a perceived change in wrist angle began at 12.0 (6.0-19.0) (median (interquatile range)) min, the change in elbow angle began at 11.0 (6.0-15.0) min. The loss of a pole perceived in a phantom hand began at 19.5 (16.0-20.0) min after the block. The initial impairment (an increase in tactile threshold) began at 19.0 (16.0-24.0) min for the hand and 25.0 (24.0-30.0) min for the elbow. The loss of a pole perceived in a phantom hand thus corresponded with the initial impairment of tactile sensation in the hand. The changes in the perceived posture of the hand and arm depended on the fading somatosensory inputs from strongly stretched muscle and skin during the anesthesia. Presumably, a pole fixed to the hand was also perceived to move towards flexion with the phantom hand extending body schema of the hand to a pole.	P2-2-120 両大脳半球への経頭蓋直流電気刺激は触覚弁別課題の成績をより促進させる Facilitative effect of dual-hemispheric transcranial direct current stimulation (tDCS) on performance in tactile discrimination task ○藤本修平1, 山口智史2,3, 大高洋平1, 定藤規弘4, 大須理英子5, 近藤国嗣1, 田中悟志6 ○Shuhei Fujimoto1, Tomofumi Yamaguchi2,3, Yohei Otaka1, Norihiro Sadato4, Rieko Osu5, Kunitsugu Kondo1, Satoshi Tanaka6 東京湾岸リハビリテーション病院1, 慶應義塾大学大学院医学研究科2, 日本学術振興会3, 生理学研究所4, 国際電気通信基礎技術研究所5, 名古屋工業大学6 Tokyo Bay Rehabilitation Hospital, Chiba, Japan1, Keio University school of Medicine, Tokyo, Japan2, Japan Society for the Promotion of Science (JSPS), Tokyo, Japan3, National Institute for Physiological Sciences, Aichi, Japan4, ATR Computational Neuroscience Laboratories, Kyoto, Japan5, Nagoya Institute of Technology, Aichi, Japan6 Background and Purpose: Transcranial direct current stimulation (tDCS) is a non-invasive technique in which weak direct currents polarize target cortical regions. tDCS increases cortical excitability and facilitates behavioral performance. Thus, tDCS has a potential to be an adjuvant strategy in physical therapy. Recently, it has shown that dual-hemispheric tDCS over the motor cortex improved motor performance more compared to conventional uni-hemispheric tDCS. However, the effect of dual-hemispheric tDCS on sensory function remains unknown. The purpose of this study was to examine the effect of dual-hemispheric tDCS over the sensory cortex (S1) on tactile discrimination function in healthy volunteers.Materials/Methods: In a double-blind, crossover and sham-controlled experimental design, 10 healthy volunteers performed a tactile discrimination task (grating orientation task: GOT) with right index finger before, during, 0 min and 30 min after tDCS. We tested the hypothesis that dual-hemispheric tDCS (1 mA, 20 min) over S1 can improve performance in the GOT task compared to uni-hemispheric tDCS over S1 and sham condition. This study was approved by the local ethics committee of Tokyo Bay Rehabilitation Hospital.Results: Performance in the GOT task was significantly improved during and 0 min after dual-hemispheric tDCS compared to uni-hemispheric tDCS and sham conditions (all, p<.05).Conclusions and Clinical Relevance: This is the first evidence that dual-hemispheric tDCS over S1 improved performance in a tactile discrimination task in healthy volunteers. This finding raises the possibility that dual-hemispheric tDCS might be a useful strategy to improve functional recovery in patients with sensory dysfunctions.
P2-2-121 脊髄神経節の機械受容性ニューロンにおけるRunx1/Runx3の共発現 Co-expression of Runx1 and Runx3 in mechanoreceptive neurons in the dorsal root ganglion ○吉川雅朗1,2, 村上佑希2, 先崎浩次2, 尾崎繁2, 相澤信1, 志賀隆2 ○Masaaki Yoshikawa1,2, Yuuki Murakami2, Koji Senzaki2, Shigeru Ozaki2, Shin Aizawa1, Takashi Shiga2 日大医・機能形態生体構造医1, 筑波大・医学医療系2 Div of Anat Sci, Dept of Funct Morphol, Nihon Univ Sch of Med, Tokyo, Japan1, Fac of Med, Univ of Tsukuba, Tsukuba, Japan2 Runt-related transcription factors (Runx) regulate the development of various cells. Recent studies have shown that Runx1 and Runx3 are expressed in subtypes of neurons in peripheral and central nervous system from the early stages of development. In dorsal root ganglion (DRG), neurons are subdivided into 3 major types: nociceptive, mechanoreceptive, and proprioceptive neurons. Runx1 and Runx3 are expressed in distinct subpopulations of DRG neurons, and play important roles in the differentiation of nociceptive and proprioceptive neurons, respectively. Although Runx1 and Runx3 appear to have complementary regulations in neuronal development, we have found that there are some DRG neurons which express both Runx1 and Runx3, raising questions about the properties of these neurons. In the present study, we examined the developmental changes of the expression of Runx1 and Runx3 in the mouse DRG during embryonic and postnatal stages. We found that the expression of Runx3 preceded that of Runx1, but dramatically decreased before birth, whereas the Runx1 expression was maintained during postnatal periods. These results suggest that roles of Runx1 and Runx3 may change dynamically in the differentiation and maturation of DRG neurons. In addition, several DRG neurons expressed both Runx1 and Runx3 throughout embryonic and postnatal stages and many Runx3-expressing DRG neurons co-expressed Runx1 at postnatal day 28. Triple labeling study suggests that some of the Runx1/Runx3-double expressing neurons expressed TrkB, c-ret, and TrkC. Because TrkB, c-ret and TrkC have been shown to be expressed by the mechanoreceptive DRG neurons, the present results suggest that Runx1/Runx3-double expressing neurons may represent mechanoreceptive properties in the DRG.	P2-2-122 ラット島皮質から疼痛受容に関わる三叉神経尾側亜核（延髄後角）および下部脳幹領域への投射について Projections from the insular cortex to pain-receptive trigeminal caudal subnucleus (medullary dorsal horn) and other lower brainstem areas in rats ○佐藤文彦1, ホックタシヌル1, 岡綾香1, 東山景一郎1, 山田謙一1, アクタファティマ1, 大原春香1, 藤尾隆史1, 山本雅章1, 内野勝郎1, 加藤隆史1, 吉田篤1 ○Fumihiko Sato1, Md. Tahsinul Haque1, Ayaka Oka1, Keiichiro Higashiyama1, Kenichi Yamada1, Mst. Fatema Akhter1, Haruka Ohara1, Takashi Fujio1, Masaaki Yamamoto1, Katsuro Uchino1, Takafumi Kato1, Atsushi Yoshida11 大阪大学大学院　歯学研究科　高次脳口腔機能学講座　口腔解剖学第二教室1 Dept of Oral Anat and Neurobiol, Osaka Univ, Osaka, Japan1 This study examined the projections from the rat insular cortex (Ins) to lower brainstem areas which are possibly involved in orofacial pain processing. We first examined distributions of Ins neurons projecting directly to the trigeminal caudal subnucleus (Vc, medullary dorsal horn) and oral subnucleus (Vo) which are known to receive orofacial nociceptive inputs. After injections of a retrograde tracer, Fluorogold (FG), into the medial part and lateral part of laminae I/II of Vc, many neurons were labeled bilaterally with a contralateral predominance in the rostral level of granular Ins (GI) and dysgranular Ins (DI) and the caudal level of GI/DI, respectively, but none in the agranular Ins (AI). After FG injections into laminae III-V of Vc, no Ins neurons were labeled. After FG injections into the Vo, many neurons were labeled bilaterally with a contralateral predominance in the rostral and caudal GI/DI, but none in the AI. We then examined descending projections from the GI/DI to the lower brainstem. After injections of an anterograde tracer, biotinylated dextranamine (BDA), into the rostral GI/DI, many BDA-labeled axons and terminals were seen bilaterally with a contralateral predominance in the medial part of laminae I/II of Vc, dorsomedial Vo, juxtatrigeminal region, rostral ventromedial medulla (RVM), and nucleus of the solitary tract, and with an ipsilateral predominance in the parabrachial nucleus (Pb), Kölliker-Fuse nucleus (KF) and trigeminal mesencephalic nucleus. After BDA injections into the caudal GI/DI, they were seen bilaterally with a contralateral predominance in the lateral part of laminae I/II of Vc, ventrolateral Vo, juxtatrigeminal region and RVM, and with an ipsilateral dominance in the lateral zone (PAGl) of periaqueductal gray, Pb and KF. These results suggest that orofacial nociceptive processing of Vc and Vo neurons may be regulated by GI/DI directly or indirectly through brainstem nuclei such as PAGl, Pb, KF and RVM.
P2-2-123 ヒト帯状回皮質は識別できない2つの機械的皮膚刺激に対して異なる応答を示す The human cingulate cortex differently responds to two perceptually indistinguishable mechanical cutaneous stimuli ○渡辺信博1, 石井賢二2, 堀田晴美1, 織田圭一2, 坂田宗之2, 豊原潤2, 石渡喜一2 ○Nobuhiro Watanabe1, Kenji Ishii2, Harumi Hotta1, Keiichi Oda2, Muneyuki Sakata2, Jun Toyohara2, Kiichi Ishiwata2 東京都健康長寿医療センター研究所　自律神経機能研究室1, 東京都健康長寿医療センター研究所　神経画像研究チーム2 Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan1, Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan2 The cutaneous sensory system plays an important role in eliciting biological reactions not only sensations, but also analgesia and autonomic responses. We previously reported that gentle mechanical cutaneous stimulation inhibits somatically-induced autonomic responses in anesthetized rats and conscious humans. Such an effect was dependent on the texture of contacting objects, while a difference in the texture was not recognized. So far, brain responses to imperceptible somatosensory stimulation are little known. In the present study, we compared brain activity in response to gentle cutaneous mechanical stimuli using the tools with different textures. Twelve healthy, young adult males participated. As an indicator of brain activity, glucose metabolism was evaluated by positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose (FDG). Cutaneous stimulation was given using two types of stimulation tools, soft elastomer discs with microcones (microcone disc) or flat surfaces (flat disc). Each type of cutaneous stimulation tool was bilaterally applied on the cheeks and FDG-PET scans were performed. The order of the stimulation tool use was allocated in a cross-over, randomized double-blind manner. During microcone disc stimulation which was previously shown to be effective for an autonomic response, FDG uptake was greater in the anterior cingulate cortex, compared with flat disc stimulation which was ineffective. In contrast, FDG uptake in the primary somatosensory cortex was not different. There was no difference in the presence of perception by cutaneous stimulation between microcone and flat discs. The present study is the first to localize a difference in brain activity in response to two types of mechanical cutaneous stimuli, which were perceptually indistinguishable, suggesting that the cingulate cortex may relate to mechanisms for effects of imperceptible somatic stimuli.	P2-2-124 頚部痛患者のトリガーポイントへの圧迫刺激による前頭前野脳血行動態及び自律神経活動の変化 Changes of cerebral hemodynamics response in the prefrontal cortex and autonomic nervous activity during pressure stimulation at myofasical trigger point in human subjects with neck pain ○高本考一1, 福田紗恵子2, 浦川将1, 堀悦郎2, 酒井重数1, 小野武年1, 西条寿夫2 ○Kouich Takamoto1, Saeko Fukuda2, Susumu Urakawa1, Etsuro Hori2, Shigekazu Sakai1, Taketoshi Ono1, Hisao Nishijo2 富山大院・医薬・神経・整復学1, 富山大院・医薬・システム情動科学2 Dept Judo Neurophysiotherapy, Grad Sch Med & Pharmaceu Sci, Univ Toyama, Toyama1, Dept System and Emotional Sci, Grad Sch Med & Pharmaceu Sci, Univ Toyama, Toyama2 It has been proposed that the musculoskeletal pain was caused by myofascial trigger points (MTrP), which defined as hyperirritable nodules of spot tenderness in a muscle taut band. Manual pressure stimulation (PS) at MTrP has been reported to be particularly beneficial to patients with musculoskeletal pain. However, the neural mechanism of pain reduction by PS at MTrP remains unclear. In the present study, we investigated effects of PS at MTrP in patients with neck pain on cerebral hemodynamic responses and autonomic nervous activity. Seventeen female patients with musculoskeletal pain of the trapezius muscles were randomly divided into two groups as the MTrP stimulation group (N = 8) and the non-MTrP stimulation group (N =9). Each subject received manual pressure stimulation for 30 sec 4 times. The examiner maintained constant pressure by monitoring a sensor on the thumb. The PS intensity was set in the middle between the pressure for pain threshold and that for maximally tolerable pain. During the experiment, cerebral hemodynamic responses (changes in Oxy-Hb, Deoxy-Hb, and Total-Hb concentration), and autonomic nervous activity based on heart rate variability (HRV) were monitored. PS at MTrP significantly decreased visual analog scale pain score compared with PS at non-MTrP. Furthermore, Oxy-Hb concentration in the anterior dorsomedial prefrontal cortex (aDMPFC) and sympathetic nervous activity were significantly decreased during PS at MTrP compared with non-MTrP, while parasympathetic nervous activity was increased during PS at MTrP. The changes in autonomic nervous activity were significantly correlated with changes in cerebral hemodynamics in the aDMPFC and visual analog scale pain score. The results suggest that PS at MTrP reduced neck pain through its effects on the PFC.
P2-2-125 ラット運動感覚野における後肢刺激応答の時空間パターンに与える前肢同時刺激の効果 Effects of forelimb stimulation on the spatiotemporal pattern of neural response evoked by hindlimb stimulation in the rat sensorimotor cortex studied with multiple site optical recording system ○濱徳行1, 伊藤眞一1, 廣田秋彦1 ○Noriyuki Hama1, Shin-Ichi Ito1, Akihiko Hirota1 島根大学　医学部　神経筋肉生理学1 Dept of Physiol, Shimane Univ Sch of Medicine, Shimane, Japan1 We have developed our optical recording system to simultaneously detect the neural activity from many portions of the in vivo rat sensorimotor cortex. The quality of single sweep record signals is high enough to analyze quantitatively. As reported previously, the neural response to hindlimb or forelimb stimulation is initiated from the respective somatotopical sites, and propagates over the entire region of the detecting area. In this study, we analyzed the effect of simultaneous forelimb stimulation on the spatiotemporal propagating pattern of the hindlimb-induced response. The rat was anesthetized with a mixture of urethane and α-chloralose, and the left somatosensory cortex was exposed and stained with a voltage sensitive dye (RH-414). Electrical stimulation (1 mA, 0.5 msec) was applied to the right hindlimb and/or forelimb. The hindlimb and forelimb responses occurred with about 28 and 21 msec latencies, respectively. When we stimulated both the limbs simultaneously, propagating waves ran into each other somewhere in between and it seemed that they did not exceed the collision line. We focused on the region where the neural response to hindlimb stimulation appeared before the collision occurred, and compared the response between "with" and "without" forelimb stimulation in this region. First, we constructed the isochrone map to analyze the propagating pattern. The propagating pattern itself was not affected by the forelimb stimulation. Then we compared the shape of the optical response signal; the peak amplitude, the slope of rising phase and full width at half amplitude (FWHA). Significant difference was found only in FWHA; it was shortened with the forelimb stimulation. Thus, the forelimb stimulation modulated the shape, but not the propagation pattern, of the response evoked by hindlimb stimulation. It was found that the neural responses to simultaneous stimulation were not simple summation of the response to the separate stimulation.	P2-2-126 ヒゲ感覚システムにおける皮質視床投射ニューロンが形成する回路と機能 Sensory representation of corticothalamic projection neurons in the vibbrisal barrel cortex of waking rats ○平井大地1, 古田貴寛1, 金子武嗣1 ○Daichi Hirai1, Takahiro Furuta1, Takeshi Kaneko1 京都大学大学院　医学研究科　高次脳形態学1 Dept. of Morphol. Brain Sci., Grad. Sch. of Med., Kyoto Univ., Kyoto, Japan1 The vibrissa sensory system is a prevalent model of sensory information processing. In the rat trigeminal pathway, sensory inputs from the face are topographically mapped onto the primary somatosensory (barrel) cortex, and the orderly arrangement of whiskers on the rat snout is represented centrally by arrays of cellular aggregates referred to as barrels. By contrast, it is still now unclear how corticothalamic circuits emanating from layer VI of the cerebral cortex are involved in sensory processing in the thalamo-cortical system, because neurons in layer VI are morphologically and physiologically diverse. In this study, we examined how cortical neurons with long-range axonal projections targeting unique sets of cortical and subcortical brain regions represent stimulus-specific causal networks. Here, the juxtacellular labeling technique (Pinault1996), which allows selective labeling and visualization of individual neurons whose discharge behavior has been electrophysiologically characterized, was applied to recordings in awake head-fixed rats. The vibrissa of rats was pushed mechanically by a piezo-driven vibrating insertion device in a given direction, and neuronal responses to the whisker stimulation were analyzed. The recorded cell was labeled juxtacellularly with TMR-cadaverine or TMR-biocytin, and immunohistologically visualized by combining the ABC method and the PAP method with the biotinylated tyramine-glucose oxidase amplification (Furuta et al., 2009). By morphological reconstruction, neurons were classified into corticothalamic and corticocortical projection neurons. As a result, we found short-latency synchronous discharges to sensory stimuli among corticothalamic projection neurons in layer VI, especially thalamo-cortical recipient (VGluT2 dense) zone. This result suggests direct evidence about corticothalamic sensory flow, which takes part in principles of the thalamo-cortical sensory system.
P2-2-127 二次運動野からのトップダウン入力による体性感覚の制御 Top-down motor signals modulate sensory perception ○真仁田聡1, 鈴木崇之1, 松元崇1, 本間千尋1, 山田一之1, 太田桂輔1, 小田川摩耶1, 松原智恵1, 大倉正道2, 佐藤正晃3,5, 中井淳一2, 林康紀2,3, ラーカムマシュー4, 村山正宜1 ○Satoshi Manita1, Takayuki Suzuki1, Takashi Matsumoto1, Chihiro Homma1, Kazuyuki Yamada1, Keisuke Ota1, Maya Odagawa1, Chie Matsubara1, Masamichi Ohkura2, Masaaki Sato3,5, Junichi Nakai2, Yasunori Hayashi2,32,3, Matthew E. Larkum4, Masanori Murayama1 理研・BSI・行動神経生理1, 埼玉大・脳科学融合研究センター2, 理研BSI3, JSTさきがけ5 Lab for Behav Neurophysiol, BSI, RIKEN, Saitama, Japan1, Saitama Univ. Brain Sci. Inst., Saitama, Japan2, BSI, RIKEN, Saitama, Japan3, Neurocure Cluster of Excellence, Humboldt Univ., Berlin, Germany4, JST PRESTO, Saitama, Japan5 Little is known about how top-down signals affects on sensory perception. Here, we studied functional and anatomical connections between the primary somatosensory cortex (S1) and the secondary motor cortex (M2), one of the sources of top-down inputs. We performed cortical voltage-sensitive dye imaging to simultaneously monitor the S1 and the M2 activities, somatic patch-clamp recording to measure membrane potential changes and dendritic calcium (Ca2+) imaging with a two-photon microscope from the L5 pyramidal neurons to investigate how the single cell integrates synaptic inputs. Local application of TTX into S1 decreased the M2 activity, and vice versa. Anatomical experiments demonstrated corticocortical connections between the two regions. M2 electrical stimulation evoked dendritic Ca2+ increase in S1 L5 pyramidal neurons, which was decreased by application of CNQX to the brain surface, indicating that the distal dendritic Ca2+ changes were mediated by synaptic inputs. The synaptic inputs from M2 evoked dendritic Ca2+ activity without back propagating action potentials showing that distal dendrites receive the synaptic inputs. We also showed that M2 inputs evoked somatic hyperpolarizations in the S1 neurons through activation of interneurons. Optogenetic manipulation of M2 axons in the S1 showed a behavioral change that is based on sensory perception. These results indicate that the M2 top-down inputs modulate the S1 activity, altering sensory perception in behaving animals.	P2-2-128 ショウジョウバエにおける末梢感覚の脳への投射様式の解明 Anatomical analysis of somatosensory projections in the fruit fly central brain ○横山健1,2, 伊藤啓1 ○Takeshi K. Yokoyama1,2, Kei Ito1 東京大学　分子細胞生物学研究所　脳神経回路分野1, 日本学術振興会2 Lab for Neural Circuit, Institute of Molecular and Cellular Biosciences, Univ of Tokyo, Tokyo1, Japanese Society for Promotion of Science, Tokyo, Japan2 Somatosensation is the basis for body-centered perception of outer world. Although recent studies revealed detailed circuit organizations and functions of various primary sensory centers of insects (visual, gustatory, olfactory, auditory, and gravity sensing), those of somatosensation has not been well understood. To analyze how somatosensory information is represented in the fly Drosophila brain, we screened Gal4 and LexAV enhancer-trap strains and identified presumptive ascending terminals from peripheral somatosensory neurons and the thoracico-abdominal ganglion (TAG) in 13 regions of the brain. In addition to the previously-reported nerve endings in the central brain, such as the aCCF-G1 in the primary gustatory center, we identifed many novel types of neurons that terminate in so-far undocumented putative somatosensory centers. These include the regions around the esophagus (VES, FLA, and medial and lateral parts of SPS/IPS), VLP, and the suboesophageal ganglion. In the TAG, many, but not all, of ascending fibers are bundled in thick fascicles. Neurons of different fascicles tend to arborize in specific arborization sites in the TAG and terminate in distinct regions of the brain. For example, presumptive afferents from the six legs (but not from wings) travel through the ventral part of the TAG and terminate at aCCF-G1 and several other parts of the brain. Conversely, those from wings and halteres ascend dorsolaterally in the TAG to project mainly in the posterior parts of the brain. Sensory neurons originating from similar parts of the body appear to terminate in several brain regions. We are further investigating detailed sensory maps in the identified terminal regions. Such effort will serve as the basis for the functional studies to elucidate somatotopic and/or modality-dependent representation of somatosensation in the fly central brain.

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