title: The unique axon trajectory of the accessory nerve is determined by intrinsic properties of the neural tube in the avian embryo.
abstract: The accessory nerve is a cranial nerve, composed of only motor axons, which control neck muscles. Its axons ascend many segments along the lateral surface of the cervical spinal cord and hindbrain. At the level of the first somite, they pass ventrally through the somitic mesoderm into the periphery. The factors governing the unique root trajectory are unknown. Ablation experiments at the accessory nerve outlet points have shown that somites do not regulate the trajectory of the accessory nerve fibres. Factors from the neural tube that may control the longitudinal pathfinding of the accessory nerve fibres were tested by heterotopic transplantations of an occipital neural tube to the cervical and thoracic level. These transplantations resulted in a typical accessory nerve trajectory in the cervical and thoracic spinal cord. In contrast, cervical neural tube grafts were unable to give rise to the typical accessory nerve root pattern when transplanted to occipital level. Our results show that the formation of the unique axon root pattern of the accessory nerve is an intrinsic property of the neural tube.
authors.affiliation: The 2nd Department of General Surgery, the First Hospital of Lanzhou University, Key Laboratory of Biotherapy and Regenerative Medicine, Gansu Province, China; Department of Neuroanatomy, Institute of Anatomy, University of Bonn, Nussallee 10 53115, Bonn, Germany; Institute of Zoology, School of Life Science, Lanzhou University, China.
authors.forename: Zhongtian
authors.initials: Z
authors.lastname: Bai
authors.affiliation: Department of Neuroanatomy, Institute of Anatomy, University of Bonn, Nussallee 10 53115, Bonn, Germany; Institute of Anatomy, Department of Anatomy and Molecular Embryology, Ruhr-University of Bochum, Bochum, Germany.
authors.forename: Qin
authors.initials: Q
authors.lastname: Pu
authors.affiliation: Department of Neuroanatomy, Institute of Anatomy, University of Bonn, Nussallee 10 53115, Bonn, Germany; Department of Anatomy and Histology, Bangladesh Agricultural University, Mymensingh, Bangladesh.
authors.forename: Ziaul
authors.initials: Z
authors.lastname: Haque
authors.affiliation: Institute of Zoology, School of Life Science, Lanzhou University, China.
authors.forename: Jianlin
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Neuroanatomy, Institute of Anatomy, University of Bonn, Nussallee 10 53115, Bonn, Germany; Department of Molecular Embryology, Institute of Anatomy and Cell Biology, University of Freiburg, Germany. Electronic address: ruijin.huang@uni-bonn.de.
authors.forename: Ruijin
authors.initials: R
authors.lastname: Huang
mesh_terms: D000055:Accessory Nerve / Q000166:cytology* / Q000196:embryology* / Q000502:physiology; D000818:Animals; D000071437:Axon Guidance / Q000502:physiology*; D002642:Chick Embryo; D054259:Neural Tube / Q000166:cytology* / Q000196:embryology* / Q000502:physiology; D019170:Somites / Q000166:cytology / Q000196:embryology* / Q000502:physiology
keywords: Accessory nerve; Branchiomotor nerve; Chick embryo; Neural tube; Somite