title: Early postnatal maturation in vestibulospinal pathways involved in neck and forelimb motor control.
abstract: To assess the organization and functional development of vestibulospinal inputs to cervical motoneurons (MNs), we have used electrophysiology (ventral root and electromyographic [EMG] recording), calcium imaging, trans-synaptic rabies virus (RV) and conventional retrograde tracing and immunohistochemistry in the neonatal mouse. By stimulating the VIIIth nerve electrically while recording synaptically mediated calcium responses in MNs, we characterized the inputs from the three vestibulospinal tracts, the separate ipsilateral and contralateral medial vestibulospinal tracts (iMVST/cMVST) and the lateral vestibulospinal tract (LVST), to MNs in the medial and lateral motor columns (MMC and LMC) of cervical segments. We found that ipsilateral inputs from the iMVST and LVST were differentially distributed to the MMC and LMC in the different segments, and that all contralateral inputs to MMC and LMC MNs in each segment derive from the cMVST. Using trans-synaptic RV retrograde tracing as well as pharmacological manipulation of VIIIth nerve-elicited synaptic responses, we found that a substantial proportion of inputs to both neck and forelimb extensor MNs was mediated monosynaptically, but that polysynaptic inputs were also significant. By recording EMG responses evoked by natural stimulation of the vestibular apparatus, we found that vestibular-mediated motor output to the neck and forelimb musculature became more robust during the first 10 postnatal days, concurrently with a decrease in the latency of MN discharge evoked by VIIIth nerve electrical stimulation. Together, these results provide insight into the complexity of vestibulospinal connectivity in the cervical spinal cord and a cogent demonstration of the functional maturation that vestibulospinal connections undergo postnatally. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1061-1077, 2016.
authors.affiliation: Laboratory of Neural Development and Optical Recording (NDEVOR), Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.|Institut De Neurosciences Cognitives Et Intégratives D'aquitaine, University of Bordeaux, CNRS UMR 5287, Bordeaux, 33076, France.
authors.forename: François M
authors.initials: FM
authors.lastname: Lambert
authors.affiliation: Institut De Neurosciences De La Timone, CNRS and Aix Marseille Université, Marseille Cedex 05, 13385, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Bras
authors.affiliation: Institut De Neurosciences Cognitives Et Intégratives D'aquitaine, University of Bordeaux, CNRS UMR 5287, Bordeaux, 33076, France.
authors.forename: Laura
authors.initials: L
authors.lastname: Cardoit
authors.affiliation: Institut De Neurosciences De La Timone, CNRS and Aix Marseille Université, Marseille Cedex 05, 13385, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Vinay
authors.affiliation: Institut De Neurosciences De La Timone, CNRS and Aix Marseille Université, Marseille Cedex 05, 13385, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Coulon
authors.affiliation: Laboratory of Neural Development and Optical Recording (NDEVOR), Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.|Norwegian Center for Stem Cell Research, Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway.
authors.forename: Joel C
authors.initials: JC
authors.lastname: Glover
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism; D005552:Forelimb / Q000254:growth & development* / Q000294:innervation / Q000502:physiology; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D009043:Motor Activity / Q000502:physiology*; D009046:Motor Neurons / Q000166:cytology / Q000502:physiology; D018482:Muscle, Skeletal / Q000254:growth & development / Q000294:innervation / Q000502:physiology; D009333:Neck / Q000254:growth & development* / Q000294:innervation / Q000502:physiology; D009434:Neural Pathways / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D013116:Spinal Cord / Q000166:cytology / Q000254:growth & development* / Q000502:physiology; D014725:Vestibular Nerve / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D014726:Vestibular Nuclei / Q000166:cytology / Q000254:growth & development* / Q000502:physiology
chemical_list: D002118:Calcium
keywords: cervical; forelimb; motoneuron; neck; postural control; vestibular development; vestibular maturation; vestibulospinal