Movement disorders such as Parkinson’s disease (PD), Huntington’s disease and dystonia are caused by neurodegeneration in the basal ganglia. In the basal ganglia, there are three pathways, i.e., direct, indirect and hyperdirect pathway. These pathways connect the cortex and output nuclei of the basal ganglia, and play important roles in motor control. We have recorded neuronal activities in the basal ganglia to clarify the mechanisms of motor control by the basal ganglia. It is also important to investigate pathophysiology in movement disorders to establish the therapy.
PD is a neurodegenerative disorder characterized by the progressive loss of nigrostriatal dopaminergic neurons. The loss of dopaminergic neurons in the substantia nigra pars compacta (SNc) induces motor dysfunction, including resting tremor, rigidity, bradykinesia. These symptoms in PD can be treated by dopamine precursor L-DOPA. However long-term L-DOPA treatment induces motor complication, L-DOPA induced dyskinesia.
In this project, we induce dyskinesia in PD model mice and record neuronal activity in the basal ganglia before and after appearance of dyskinesia. We also modulate neuronal activity in the basal ganglia by using optogenetics and observe whether involuntary movements, such as dyskinesia are induced. In addition, we recover the neuronal activity in dyskinesia to normal state by optogenetic modulation and observe whether involuntary movements are disappeared. These studies will reveal the relation between neuronal activity and involuntary movements in L-DOPA induced dyskinesia.

Recent Publications
1. Sano H, Murata M, Nambu A (2015) Zonisamide reduces nigrostriatal dopaminergic neurodegeneration in a mouse genetic model of Parkinson’s disease. J Neurochem134(2):371-81.
2. Sano H, Chiken S, Hikida T, Kobayashi K, Nambu A (2013) Signals through the striatopallidal indirect pathway stop movements by phasic excitation in the substantia nigra. J Neurosci. 33(17):7583-94.
3. Bepari AK, Sano H, Tamamaki N, Nambu A, Tanaka KF, Takebayashi H (2012) Identification of optogenetically activated striatal medium spiny neurons by Npas4 expression. PLoS One 7(12):e52783.
4. Tanaka KF, Matsui K, Sasaki T, Sano H, Sugio S, Fan K, Hen R, Nakai J, Yanagawa Y, Hasuwa H, Okabe M, Deisseroth K, Ikenaka K, Yamanaka A (2012) Expanding the repertoire of optogenetically targeted cells with an enhanced gene expression system. Cell Rep 2(2):397-406.

Many patients with spinal cord injuries (SCIs) suffer severe paralysis. Injured adult neurons in the mammalian CNS rarely regenerate, because some of the intracellular and cell-surface environmental factors inhibit axon regrowth. Chondroitin sulfate (CS), a glycosaminoglycan (GAG), is the most abundant and potent exogenous inhibitor of axonal regeneration and CS degradation induces some of the axonal regrowth following SCI by treatment of chondroitinase ABC (ChABC). We generated null (KO) mice of CS N-acetylgalactosaminyltransferase-1 (CSGalNAcT1), a key enzyme in CS biosynthesis (Watanabe, Takeuchi et al., Biochem J 432: 47). Here, we show that KO mice recovered much faster and more completely from induced SCI than do wild-type mice and even ChABC treatment mice (Takeuchi K., et al, Nature Communication 4 : 2740 (2013)). Following SCI, KO mice showed smaller areas of glial and fibrotic scars and exhibited many more regenerated axon terminals. Additionally, synthesis of another type of GAG, heparan sulfate (HS), was up-regulated extraordinarily at the injury sites only in KO mice. Taken together, our results indicated that CSGalNAcT1 influenced the extraordinary recovery from SCI by modulating the balance of synthesis of CS and HS, and that CSGalNAcT1 is a promising best therapeutic target for treatment of the neural damage. We try to promote the therapeutic methods to cure the injuries of central nervous system, from the viewpoints that the new trial to regulate the expressions of glycosaminoglycans as the circumstances of the neuron. From these projects, we aim to show the mechanisms of re-organization following the neural circuit injury, by using new techniques to manipulate the glycosaminoglycans as neural circumstances and environments.

 

Analysis of the re-organizing neuronal circuits from the spinal cord injury, by using the virus tracing system.

 
 
Recent Publications
1. Takeuchi K., Yoshioka N., Higa S., Watanabe Y., Miyata S., Wada Y., Kudo C., Okada M.., Ohko K., Oda K., Sato T., Yokoyama M., Matsushita N., Nakamura M., Okano H., Sakimura K., Kawano H., Kitagawa H. and Igarashi M. (2013)　 Chondroitin sulphate N-acetylgalactosaminyltransferase-1 inhibits recovery from neural injury. Nature Communication 4 : 2740 (2013)
2. Okamoto M., Namba T., Shinoda T., Kondo T., Watanabe T., Inoue Y., Takeuchi K., Enomono Y.,Ota K., Oda K., Wada Y., Sagou K., Saito K., Sakakibara A., Kawaguchi A., Nakajima K., Fujimori T., Ueda M., Hayashi S., Kaibuchi K. and Miyata T. (2013) TAG-1-assisted progenitor elongation streamlines nuclear migration to optimize subapical crowding. Nature Neuroscience 16 : 1556-1566
3. Namba T., Kibe Y., Funahashi Y., Nakamuta S., Takano T., Ueno T., Shimada A., Kozawa S., Okamoto M., Shimoda Y., Oda K., Wada Y., Masuda T., Sakakibara A., Igarashi M., Miyata T., Faivre-Sarrailh C., Takeuchi K. and Kaibuchi K. (2014) Pioneering Axons Regulate Neuronal Polarization in the Developing Cerebral Cortex. Neuron 81: 814-829

Sensory experience is recognized as a critical factor in the development and plastic modification of neural circuits in vertebrates. As well as newborn hippocampal neurons, newborn olfactory bulb (OB) interneurons are a good model for studying the postnatal modification of neural circuits by sensory inputs from the external world. Precursors for OB interneurons are generated throughout life in the subventricular zone of the lateral ventricle, migrate along the rostral migratory stream and differentiate into GABA-releasing inhibitory interneurons, such as periglomerular cells and granule cells. It is well known that odor-evoked neural activity affects the survival and integration of newborn OB interneurons. Moreover, odor-deprivation and odor-enriched environments suppress and facilitate, respectively, dendritogenesis and spinogenesis in newborn OB interneurons. However, molecular mechanisms regulating the sensory experience-dependent dendritogenesis and spinogenesis in OB newborn interneurons remain unknown. Recently, we found that the 5T4 oncofetal trophoblast glycoprotein regulates the dendritic arborization of OB GCs in a sensory input-dependent manner (Yoshihara et al., 2012; Takahashi et al., 2016), whereas the neuronal Per/Arnt/Sim domain protein 4 (Npas4) transcription factor controls the sensory input-dependent dendritic spine formation of OB GCs (Yoshihara et al., 2014). In the current project of “Adaptive Circuit Shift”, we will aim at applying newborn OB interneurons to functional recovery of neural circuits in the ischemic brain.

 
Recent Publications
1. Takahashi H, Ogawa Y, Yoshihara S, Asahina R, Kinoshita M, Kitano T, Kitsuki M, Tatsumi K, Okuda M, Tatsumi K, Wanaka A, Hirai H, Stern PL, Tsuboi A (2016) A subtype of olfactory bulb interneurons is required for odor detection and discrimination behaviors. J Neurosci in press.
2. Yoshihara S, Takahashi H, Nishimura N, Kinoshita M, Asahina R, Kitsuki M, Tatsumi K, Furukawa-Hibi Y, Hirai H, Nagai T, Yamada K, Tsuboi A (2014) Npas4 regulates Mdm2 and thus Dcx in experience-dependent dendritic spine development of newborn olfactory bulb interneurons. Cell Rep 8:843-857.
3. Yoshihara S, Takahashi H, Nishimura N, Naritsuka H, Shirao T, Hirai H, Yoshihara Y, Mori K, Stern PL, Tsuboi A (2012) 5T4 glycoprotein regulates the sensory input-dependent development of a specific subtype of newborn interneurons in the mouse olfactory bulb. J Neurosci 32:2217-2226.

Intensive rehabilitation after stroke has a big influence on the reorganization of the neural circuit and is an effective method to lead the recovery of motor function. It is suggested that the adaptive shift to a new neural circuit participates in the process.
Our group developed an internal capsule (IC) hemorrhage model rat that had a small hemorrhage limited to the bottleneck part of the cortico-spinal tract. Using this IC model rat, we challenge to examine the effect of forced-limb use (FLU) after the hemorrhage on the recovery of motor function with the investigation of the mechanism in adaptive shift to a new circuit of the central nervous system.
We revealed that early FLU after IC hemorrhage by the restriction of the non-paralysis limb (normal side) caused the recovery of skilled forelimb function. We also clarified that cortical map of forelimb area was expanded by intensive FLU accompanied with increased projection of cortico-rubral tract in red nucleus. With the collaboration with Isa’s group, double virus infection was performed to confirm the causality of recovered forelimb function with enhanced cortico-rubral projections.
We will perform more detailed analysis about the FLU effect and the relationship of the cortex – red nucleus pathway. Selective inhibition of this pathway during FLU might clarify the mechanism of FLU effect on adaptive shift to a new neural circuit in the brain.

 
Recent Publications
1. Ishida A, Isa K, Umeda T, Kobayashi K, Kobayashi K, Hida H, Isa T. Causal link between the cortico-rubral pathway and functional recovery through forced impaired limb use in rats with stroke. J Neurosci. 36(2):455-67, 2016
2. Ishida A, Misumi S, Ueda Y, Shimizu S, Jung C-G, Tamakosh K, Ishida I, Hida H. Early constraint-induced movement therapy promotes functional recovery and neuronal plasticity in a subcortical hemorrhage model rat. Behav Brain Res. 284, 158-66, 2015
3. Ueda,Y, Masuda T, Ishida A, Misumi S. Shimizu, Y, Jung C-G, Hida H.Enhanced electrical responsiveness in the cerebral cortex with oral melatonin administration after a small hemorrhage near the internal capsule in rats J Neurosci Res, 92(11): 1499-508, 2014.
4. Ishida A, Tamakoshi K, Hamakawa M, Shimada H, Nakashima H, Masuda T, Hida H, Ishida K. Early onset of forced impaired forelimb use causes recovery of forelimb skilled motor function but no effect on gross sensory-motor function after capsular hemorrhage in rats. Behav Brain Res. 225(1):126-34. 2011

Although adult neurogenesis is a common phenomenon in the non-mammalian neocortex, the scale of adult neurogenesis in the neocortex appears to decrease significantly as the phylogeny approaches the human being. In apparent contrast, the limbic area of the telencephalon appears to be a site of continuous generation of neurons. In particular, the medial edge of the mammalian telencephalon, the dentate gyrus, produces granule cells constantly throughout life in humans, while the subventricular zone (SVZ) surrounding the lateral ventricle continuously produces GABAergic granule cells for the olfactory bulb. Granule cells produced in the dentate gyrus are integrated into the circuitry of the hippocampus and save new information, whereas granule cells produced in the SVZ of the lateral ventricle migrate rostrally and are integrated into the olfactory circuitry. In other words, these new neurons are not integrated into the neocortex. However, if a significant number of new neurons is produced in the neocortex and integrated into the neocortical circuit, we cannot deny the possibility that these new neurons ruin the circuits for memory and thought in the human neocortex. On the other hand, Macklis expressed repellence that the synchronous apoptotic degeneration of corticothalamic neurons may induce generation of the same number of neurons in the neocortex and may recreate the same circuit as was originally present. In this case, neurogenesis in the neocortex will not disturb the circuit in the neocortex, and would be welcomed. Therefore, our goal is to find out the hidden neuron progenitors around the neocortex, and stimulate the neuron progenitors to turn them into neurons. I will have an honor to show you how the neocortex maintain its function so long in our brain.

Recent Publications
1. Yamaguchi M, Seki T, Imayoshi I, Tamamaki N, Hayashi Y, Tatebayashi Y, Hitoshi S. (2015) Neural stem cells and neuro/gliogenesis in the central nervous system: understanding the structural and functional plasticity of the developing, mature, and diseased brain. J Physiol Sci. 2015 Nov 17.
2. Huang J, Chen J, Wang W, Wei YY, Cai GH, Tamamaki N, Li YQ, Wu SX. (2013) Birthdate study of GABAergic neurons in the lumbar spinal cord of the glutamic acid decarboxylase 67-green fluorescent protein knock-in mouse.Front Neuroanat. 2013 Dec 9;7:42.
3. Ninomiya S, Esumi S, Ohta K, Fukuda T, Ito T, Imayoshi I, Kageyama R, Ikeda T, Itohara S,Tamamaki N. (2013) Amygdala kindling induces nestin expression in the leptomeninges of the neocortex. Neurosci Res. 2013 Feb;75(2):121-9.

In this study, the objective is to clarify the mechanism controlling the plasticity of the central voluntary movement circuit. In studies until now, after central nervous system damage, we have clarified that the corticospinal tract to control the motor function forms a side branch at the level of the cervical spinal cord from axons that have escaped damage and forms new circuits to interneurons. Further, the reorganization phenomenon of motor nerve circuits to establish a system in vivo to clearly evaluate and identify molecules involved in plasticity control of neural circuits. From the above study, we were able to answer to some extent the question of how the corticospinal tract forms the lower pathway leading to peripheral nerves. In this study, first by using a neural repair model after brain disorder, we will conduct the elucidation of the mechanism of neuronal circuits of the upper level to control the plasticity of voluntary movement nerve circuits. In the first year, we will verify the possibility that dopaminergic meso-cortical projection produces the plasticity of the primary motor cortex and further conduct the analysis of the mechanism. By meso-cortical projection to form a synapse in the corticospinal tract neurons, in order to answer the question of whether the plasticity of the corticospinal tract is induced, we will verify using the technology of the meso-cortical projection specific inactivation. In the second year, based also on the foundation of the results of CREST research to be completed in the previous year, we will comprise the upper and lower corticospinal tract, and in an integrated manner, approach how to achieve the plasticity changes in the voluntary movement system. More specifically, over time and comprehensively analyzing the gene expression changes in the corticospinal tract neurons after unilateral brain disorders, we will identify the molecules necessary for plasticity control of the corticospinal tract. By clarifying the molecular mechanisms that controls voluntary movement circuit in vivo, we make the objective to elucidate the mechanism of neural reorganization in adults. By applying the obtained results and strengthening the mechanism to induce the plasticity of the corticospinal tract, we make the final objective to find the molecular target to effectively improve motor dysfunction.

Recent Publications
1. Ueno, M., Fujiki, R. and Yamashita, T. (2014) A selector orchestrates cortical function. Nat. Neurosci. 17: 1016-1017.
2. Ueno, M., Fujita, Y., Tanaka, T., Nakamura, Y., Kikuta, J., Ishii, M. and Yamashita, T. (2013) Layer V cortical neurons require microglial support for survival during postnatal development. Nature Neurosci. 16: 543-551.
3. Muramatsu, R., Takahashi, C., Miyake, S., Fujimura, H., Mochizuki, H. and Yamashita, T. (2012) Angiogenesis induced by CNS inflammation promotes neural remodeling through vessel-derived prostacyclin. Nature Medicine 18: 1658-1664.
4. Muramatsu, R., Kubo, T., Mori, M., Nakamura, Y., Fujita, Y., Akutsu, T., Okuno, T., Taniguchi, J., Kumanogoh, A., Yoshida, M., Mochizuki, H., Kuwabara, S. and Yamashita, T. (2011) RGMa modulates T cell responses and is involved in autoimmune encephalomyelitis. Nature Medicine 17: 488-494.

Lesions of the corticospinal tract (CST) cause spinal cord injury (SCI) that is characterized by motor impairments involved in the spinal levels below the lesions. It has been considered that compensatory events due to plastic changes of CST neurons exert essential roles in recovery of motor functions after SCI. However, the mechanisms underlying the functional recovery and CST reorganization remain unclear. The purpose of the present work is to identify the compensatory changes of CST circuits and elucidate the mechanisms underlying the functional recovery from SCI in adult macaques. To do so, neuroanatomical approaches are taken using anterograde and retrograde tracings and transneuronal labeling with rabies virus. In this study, a primate model of SCI is prepared by unilateral lesions at the level between the C7 and the C8 spinal segment. Also, both the Brinkman board test and the reaching/grasping task are applied for behavioral analyses of dexterous manual movements.

Recent Publications
1. McCairn KW, Nagai Y, Hori Y, Ninomiya T, Kikuchi E, Lee J-Y, Suhara T, Iriki A, Minamimoto T,Takada M, Isoda M, Matsumoto M (2016) A primary role for nucleus accumbens and related
limbic network in vocal tics. Neuron 89:300-307
2. Kawai T, Yamada H, Sato N, Takada M, Matsumoto M (2015) Roles of the lateral habenula and anterior cingulate cortex in negative outcome monitoring and behavioral adjustment in
nonhuman primates. Neuron 88:792-804.
3. Inoue K, Takada M, Matsumoto M (2015) Neuronal and behavioral modulations by pathway-selective optogenetic stimulation of the primate oculomotor system. Nat Commun 6:8378.
4. Nakagawa H, Ninomiya T, Yamashita T, Takada M (2015) Reorganization of corticospinal tract fibers after spinal cord injury in adult macaques. Sci Rep 5:11986.

Recognition and discrimination of surrounding environments depends on the spatial pattern separation ― a neural process that requires the neural circuit between the entorhinal cortex and hippocampus, where the high-threshold glutamatergic synaptic inputs toward the granule cells of the dentate gyrus (DG) plays a critical role. Despite the theory/circuit-level understanding of the mechanism of the spatial pattern separation, underlying molecular mechanism remains unclear. Our unbiased behavioral screening of mice that lack a septin subunit showed their normal performance in spatial orientation, working memory, and tone-cued associative fear memory. Intriguingly, however, they selectively underperform in paradigms that require differentiation of distinct spatial contexts. To define brain regions and neuronal populations responsible for the phenotype, and to exclude possible developmental anomalies, we have conducted a local, acute depletion of the septin subunit in DG granule cells by injecting shRNA-expressing AAV vectors in adult mice, followed by spatial differentiation task. Successful recapitulation of the null phenotype demonstrates that acute, partial loss of the septin subunit in a subset of DG granule cells is sufficient to impair spatial cognition. The morphological and functional defects of the DG neurons in vivo and in vitro are under investigation.

 
Recent Publications
1. Ageta-Ishihara N, Kinoshita M et al., A CDC42EP4/septin-based perisynaptic glial scaffold facilitates glutamate clearance. Nature Communications 6:10090, 2015.
2. Hattori Y, Kinoshita M, Ihara M et al., SIRT1 counters cerebral hypoperfusion injury by deacetylating eNOS. Stroke 45, 3403-3411, 2014.
3. Ageta-Ishihara N, Bito H, Kinoshita M et al., Septins promote dendrite and axon development by negatively regulating microtubule stability via HDAC6-mediated deacetylation. Nature Communications 4, 2532, 2013.
4 Ageta-Ishihara N, Kinoshita M et al., Chronic overload of SEPT4, a parkin substrate that aggregates in Parkinson’s disease, causes behavioral alterations but not neurodegeneration in mice. Molecular Brain 6, 35, 2013.
5. Ihara M, Kinoshita M et al. Sept4, a component of presynaptic scaffold and Lewy bodies, is required for the suppression of α-synuclein neurotoxicity. Neuron 53, 519-533, 2007.

We use optogenetics or pharmacogenetics to control the activity of targeted neurons in vivo. Alternatively the fate of targeted neurons is controlled to reveal physiological role of these targeted neurons. We focused on instinctive behaviors such as feeding, drinking, sexual behavior and sleep/wakefulness regulation. In this study, we study the role of orexin neurons in the hypothalamus. These neurons are implicated in the regulation of sleep/wakefulness. Specific degeneration of these neurons is caused by sleep disorder Narcolepsy. Symptom of Narcolepsy is excessive day-time sleepiness, sudden muscle weakness called cataplexy. Not only these symptoms,Narcolepsy patients show abnormality of metabolism. Recently we generated new narcolepsy model mice which enable ablate orexin neurons in specific timing. These mice perfectly mimic all symptoms seen in human Narcolepsy. The aim of this study is to reveal mechanism of narcolepsy symptoms by the adoptive circuit shift after ablation of orexin neurons.We use optogenetics or pharmacogenetics to control the activity of targeted neurons in vivo. Alternatively the fate of targeted neurons is controlled to reveal physiological role of these targeted neurons. We focused on instinctive behaviors such as feeding, drinking, sexual behavior and sleep/wakefulness regulation. In this study, we study the role of orexin neurons in the hypothalamus. These neurons are implicated in the regulation of sleep/wakefulness. Specific degeneration of these neurons is caused by sleep disorder Narcolepsy. Symptom of Narcolepsy is excessive day-time sleepiness, sudden muscle weakness called cataplexy. Not only these symptons,Narcolepsy patients show abnormality of metabolism. Recently we generated new narcolepsy model mice which enable ablate orexin neurons in specific timing. These mice perfectly mimic all symptoms seen in human Narcolepsy. The aim of this study is to reveal mechanism of narcolepsy symptoms by the adoptive circuit shift after ablation of orexin neurons.

 
Recent Publications
1. Tabuchi S, Tsunematsu T, Black SW, Tominaga M, Maruyama M, Takagi K, Minokoshi Y, Sakurai T, Kilduff TS, Yamanaka A (2014) Conditional ablation of orexin/hypocretin neurons: a new mouse model for the study of narcolepsy and orexin system function. J Neurosci 34:6495-6509.
2. Tsunematsu T, Ueno T, Tabuchi S, Inutsuka A, Tanaka KF, Hasuwa H, Kilduff TS, Terao A, Yamanaka A (2014) Optogenetic manipulation of activity and temporally controlled cell-specific ablation reveal a role for MCH neurons in sleep/wake regulation. J Neurosci 34:6896-6909.
3. Inutsuka A, Inui A, Tabuchi S, Tsunematsu T, Lazarus M, Yamanaka A (2014) Concurrent and robust regulation of feeding behaviors and metabolism by orexin neurons. Neuropharmacology 85:451-460.

The brain uses various types of eye movement subsystems to receive visual input properly; saccadic eye movement occurs when a stimulating target appears in front of us, smooth pursuit and convergence eye movements occur when looking at a slow moving visual target, and the vestibuloocular reflex (VOR) occurs when looking at a static visual target under head free environment. Eye movements should be three-dimensional (horizontal, vertical and torsional around the visual line), since an eyeball is a rigid body. However, in the saccadic system, eye movements are two-dimensional rather than three-dimensional, although the torsional movements occur in the VOR. This phenomenon (the torsional component does not occur in saccades) is known as Listing’s law, but the neural circuit implementing this law has not been understood for a long time.
In this project, we will analyze the neural pathways from the superior colliculi to ocular motoneurons in the vertical saccade system with electrophysiological methods including intracellular recording in the monkey, and determine the coordinate system that the saccade system uses. Based on the information of such identified neural circuits, we will try to selectively and reversibly block each component of the circuits to find the circuit responsible for implementing Listing law. For this purpose, the double virus vector infection method, in which two different types of virus vectors are injected into monosynaptically connected areas, one for antidromic infection and the other for orthodromic infection, is applied in the trained monkey.

Recent Publications
1. Takahashi M, Sugiuchi Y and Shinoda Y (2014) Convergent synaptic inputs from the caudal fastigial nucleus and the superior colliculus onto pontine and pontomedullary reticular neurons. J. Neurophysiol. 111; 849-867.
2. Takahashi M, Sugiuchi Y and Shinoda Y (2010) Topographic organization of excitatory and inhibitory commissural connections in the superior colliculi and their functional roles in saccade generation. J. Neurophysiol.104; 3146-3167.
3. Takahashi M, Sugiuchi Y and Shinoda Y (2007) Commissural mirror-symmetric excitation and reciprocal inhibition between the two superior colliculi and their roles in vertical and horizontal eye movements. J. Neurophysiol. 98: 2664-2682.