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Koichi Kawakami - One of the best experts on this subject based on the ideXlab platform.
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protocadherin mediated cell repulsion controls the central topography and efferent projections of the Abducens Nucleus
Cell Reports, 2018Co-Authors: Kazuhide Asakawa, Koichi KawakamiAbstract:Summary Cranial motor nuclei in the brainstem innervate diverse types of head and neck muscles. Failure in establishing these neuromuscular connections causes congenital cranial dysinnervation disorders (CCDDs) characterized by abnormal craniofacial movements. However, mechanisms that link cranial motor nuclei to target muscles are poorly understood at the molecular level. Here, we report that protocadherin-mediated repulsion mediates neuromuscular connection in the ocular motor system in zebrafish. We identify pools of Abducens motor neurons that are topographically arranged according to soma size and convergently innervate a single muscle. Disruptions of Duane retraction syndrome-associated transcription factors reveal that these neurons require Mafba / MAFB, but not Sall4/SALL4, for differentiation. Furthermore, genetic perturbations of Pcdh17/protocadherin-17 result in defective axon growth and soma clumping, thereby abolishing neuromuscular connectivity. Our results suggest that protocadherin-mediated repulsion forms the central topography and efferent projection pattern of the Abducens Nucleus following Mafba-dependent specification and imply potential involvement of protocadherins in CCDD etiology.
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Protocadherin-Mediated Cell Repulsion Controls the Central Topography and Efferent Projections of the Abducens Nucleus
Elsevier, 2018Co-Authors: Kazuhide Asakawa, Koichi KawakamiAbstract:Summary: Cranial motor nuclei in the brainstem innervate diverse types of head and neck muscles. Failure in establishing these neuromuscular connections causes congenital cranial dysinnervation disorders (CCDDs) characterized by abnormal craniofacial movements. However, mechanisms that link cranial motor nuclei to target muscles are poorly understood at the molecular level. Here, we report that protocadherin-mediated repulsion mediates neuromuscular connection in the ocular motor system in zebrafish. We identify pools of Abducens motor neurons that are topographically arranged according to soma size and convergently innervate a single muscle. Disruptions of Duane retraction syndrome-associated transcription factors reveal that these neurons require Mafba/MAFB, but not Sall4/SALL4, for differentiation. Furthermore, genetic perturbations of Pcdh17/protocadherin-17 result in defective axon growth and soma clumping, thereby abolishing neuromuscular connectivity. Our results suggest that protocadherin-mediated repulsion forms the central topography and efferent projection pattern of the Abducens Nucleus following Mafba-dependent specification and imply potential involvement of protocadherins in CCDD etiology. : Cranial neuromuscular systems have been relatively unexplored, because of their restricted tissue accessibility. Using zebrafish, Asakawa and Kawakami develop a model system to analyze cranial neuromuscular connectivity and find that protocadherin-mediated repulsion plays crucial roles for connecting the Abducens Nucleus to the lateral rectus muscle. Keywords: mnr2b, pcdh17, mafb, sall4, zebrafish, DRS, strabismus, lateral rectus, rhombomere, motor neuro
Kazuhide Asakawa - One of the best experts on this subject based on the ideXlab platform.
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protocadherin mediated cell repulsion controls the central topography and efferent projections of the Abducens Nucleus
Cell Reports, 2018Co-Authors: Kazuhide Asakawa, Koichi KawakamiAbstract:Summary Cranial motor nuclei in the brainstem innervate diverse types of head and neck muscles. Failure in establishing these neuromuscular connections causes congenital cranial dysinnervation disorders (CCDDs) characterized by abnormal craniofacial movements. However, mechanisms that link cranial motor nuclei to target muscles are poorly understood at the molecular level. Here, we report that protocadherin-mediated repulsion mediates neuromuscular connection in the ocular motor system in zebrafish. We identify pools of Abducens motor neurons that are topographically arranged according to soma size and convergently innervate a single muscle. Disruptions of Duane retraction syndrome-associated transcription factors reveal that these neurons require Mafba / MAFB, but not Sall4/SALL4, for differentiation. Furthermore, genetic perturbations of Pcdh17/protocadherin-17 result in defective axon growth and soma clumping, thereby abolishing neuromuscular connectivity. Our results suggest that protocadherin-mediated repulsion forms the central topography and efferent projection pattern of the Abducens Nucleus following Mafba-dependent specification and imply potential involvement of protocadherins in CCDD etiology.
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Protocadherin-Mediated Cell Repulsion Controls the Central Topography and Efferent Projections of the Abducens Nucleus
Elsevier, 2018Co-Authors: Kazuhide Asakawa, Koichi KawakamiAbstract:Summary: Cranial motor nuclei in the brainstem innervate diverse types of head and neck muscles. Failure in establishing these neuromuscular connections causes congenital cranial dysinnervation disorders (CCDDs) characterized by abnormal craniofacial movements. However, mechanisms that link cranial motor nuclei to target muscles are poorly understood at the molecular level. Here, we report that protocadherin-mediated repulsion mediates neuromuscular connection in the ocular motor system in zebrafish. We identify pools of Abducens motor neurons that are topographically arranged according to soma size and convergently innervate a single muscle. Disruptions of Duane retraction syndrome-associated transcription factors reveal that these neurons require Mafba/MAFB, but not Sall4/SALL4, for differentiation. Furthermore, genetic perturbations of Pcdh17/protocadherin-17 result in defective axon growth and soma clumping, thereby abolishing neuromuscular connectivity. Our results suggest that protocadherin-mediated repulsion forms the central topography and efferent projection pattern of the Abducens Nucleus following Mafba-dependent specification and imply potential involvement of protocadherins in CCDD etiology. : Cranial neuromuscular systems have been relatively unexplored, because of their restricted tissue accessibility. Using zebrafish, Asakawa and Kawakami develop a model system to analyze cranial neuromuscular connectivity and find that protocadherin-mediated repulsion plays crucial roles for connecting the Abducens Nucleus to the lateral rectus muscle. Keywords: mnr2b, pcdh17, mafb, sall4, zebrafish, DRS, strabismus, lateral rectus, rhombomere, motor neuro
Steven L. Galetta - One of the best experts on this subject based on the ideXlab platform.
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editors note teaching video neuroimages palsy of conjugate horizontal gaze and face due to isolated Abducens nuclear infarction
Neurology, 2018Co-Authors: Megan Alcauskas, Steven L. GalettaAbstract:In reference to “Teaching Video NeuroImages: Palsy of conjugate horizontal gaze and face due to isolated Abducens nuclear infarction,” Dr. Miller points out that the title may mislead readers into thinking that both the horizontal gaze palsy and the facial nerve palsy were caused by the Abducens nuclear infarction, rather than the ipsilateral facial palsy being caused by damage to the facial nerve fascicles bordering the Abducens Nucleus. Author Kim agrees with Dr. Miller's concerns and has issued a correction to the title, changing it to “Palsy of conjugate horizontal gaze and face due to a restricted infarction involving the Abducens Nucleus.” The correction appears on page 942. In reference to “Teaching Video NeuroImages: Palsy of conjugate horizontal gaze and face due to isolated Abducens nuclear infarction,” Dr. Miller points out that the title may mislead readers into thinking that both the horizontal gaze palsy and the facial nerve palsy were caused by the Abducens nuclear infarction, rather than the ipsilateral facial palsy being caused by damage to the facial nerve fascicles bordering the Abducens Nucleus.
Jeong Yoon Choi - One of the best experts on this subject based on the ideXlab platform.
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teaching video neuro images palsy of conjugate horizontal gaze and face due to isolated Abducens nuclear infarction
Neurology, 2017Co-Authors: Seong Hae Jeong, Jeong Yoon ChoiAbstract:A 58-year-old woman presented leftward conjugate gaze palsy and left facial nerve palsy of a peripheral pattern due to acute infarction restricted to the area of left Abducens Nucleus (figure, A–C; video at [Neurology.org][1]). [1]: http://neurology.org/lookup/doi/10.1212/WNL.0000000000004543
Luigi Fabrizio Rodella - One of the best experts on this subject based on the ideXlab platform.
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immunohistochemical study of neurons in the rat Abducens Nucleus that project to the flocculus
Journal of Anatomy, 1996Co-Authors: Luigi Fabrizio Rodella, R Rezzani, R BianchiAbstract:The neurons of the rat Abducens Nucleus that project to the flocculus of the cerebellum were studied by double labelling using the retrograde transport of horseradish peroxidase (HRP) and choline acetyltransferase (ChAT) immunohistochemistry. Double-labelled cells were present bilaterally in the dorsal and dorsomedial zones of the cranial pole of the Nucleus. They represented about half of the total number of HRP-positive neurons. These findings show the existence of a bilateral projection from the Abducens Nucleus to the flocculus which uses acetylcholine as a neurotransmitter. This projection could be part of the system of the nerve circuits through which the cerebellum modulates visual activities.
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cytoarchitecture of the Abducens Nucleus of man a nissl and golgi study
Cells Tissues Organs, 1996Co-Authors: R Bianchi, Luigi Fabrizio Rodella, R Rezzani, M GioiaAbstract:The Abducens Nucleus is a pontine Nucleus directly involved in oculomotion through its connections with the lateral rectus muscle of the eye. The aim of the present study was to investigate the cytoarchitectural organization of the Abducens Nucleus in man. The data obtained showed that the nerve cell bodies were small, medium and large in size and polygonal, oval, round or spindle shaped. The cytoplasm of all neurons appeared basophilic due to clearly evident scattered Nissl granules. On the basis of the characteristics of the dendritic arborization, multipolar and fusiform cells were identified. The multipolar neurons showed four to eight primary dendrites which gave off a wide secondary ramification. The fusiform neurons showed two dendrites emerging from the opposite poles of the elongated nerve cell body. The dendrites of all the neurons were largely confined within the boundaries of the Nucleus. This finding would suggest that the neuronal relationships of the Abducens Nucleus supplied by the afferent fibers which pass through or end within it take place almost completely inside the Nucleus. The wider dendritic arborization shown by the multipolar cells would indicate the latter as the principal target fields for the afferent inputs.
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a light and electron microscope study of rat Abducens Nucleus neurons projecting to the cerebellar flocculus
Journal of Anatomy, 1995Co-Authors: Luigi Fabrizio Rodella, R Rezzani, Giovanni Corsetti, Alessandra Stacchiotti, C Simonetti, R G VenturaAbstract:Injection of horseradish peroxidase (HRP) into the cerebellar flocculus of the rat was employed to identify neurons in the Abducens Nucleus that project to the flocculus. The number, ultrastructural features and precise localisation of these neurons in the Nucleus were examined. They were present bilaterally and represented about 7% of the total neuronal population of each Nucleus. They were localised principally in the dorsomedial area of the cranial half of each Nucleus and did not display the typical ultrastructural features of motoneurons. It is concluded that the localisation and ultrastructural characteristics of these HRP-positive neurons are useful for distinguishing them from other neuronal populations within the Nucleus.
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the rat Abducens Nucleus a histo and immunohistochemical study
Bollettino della Società italiana di biologia sperimentale, 1994Co-Authors: Luigi Fabrizio Rodella, R Rezzani, Giovanni Corsetti, Alessandra Stacchiotti, R G VenturaAbstract:The number and proportion of motoneurons and interneurons present in the rat Abducens Nucleus was determined by the use of ChAT immunostaining and of HRP staining after retrograde transport from the injected right lateral rectus muscle. After HRP injection 67% of Abducens neurons took up HRP and were hence motoneurons to the muscle. The cell bodies were mainly located in the middle third of the Nucleus and were either spindle-shaped or pyriform. By ChAT-immunohistochemistry, 77% of the rat Abducens neurons were ChAT-positive. After considering and discarding the hypotheses that the lateral rectus muscle could be incompletely filled by HRP, and that other muscles may be innervated by Abducens motoneurons, it is concluded that some interneurons of the Abducens Nucleus of the rat are probably cholinergic.