Publication

Influence of Brain Stem on Axial and Hindlimb Spinal Locomotor Rhythm Generating Circuits of the Neonatal Mouse

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Last modified
  • 05/15/2025
Type of Material
Authors
    Céline Jean-Xavier, Emory UniversityMarie-Claude Perreault, Emory University
Language
  • English
Date
  • 2018-02-09
Publisher
  • Frontiers Media
Publication Version
Copyright Statement
  • © 2018 Jean-Xavier and Perreault.
License
Final Published Version (URL)
Title of Journal or Parent Work
ISSN
  • 1662-4548
Volume
  • 12
Issue
  • FEB
Start Page
  • 53
End Page
  • 53
Grant/Funding Information
  • This research was supported by the International Foundation for Research on Paraplegia (IRP), the Craig H. Neilsen Foundation and the National Institutes of Health (NIH) grant R01 NS085387.
Supplemental Material (URL)
Abstract
  • The trunk plays a pivotal role in limbed locomotion. Yet, little is known about how the brain stem controls trunk activity during walking. In this study, we assessed the spatiotemporal activity patterns of axial and hindlimb motoneurons (MNs) during drug-induced fictive locomotor-like activity (LLA) in an isolated brain stem-spinal cord preparation of the neonatal mouse. We also evaluated the extent to which these activity patterns are affected by removal of brain stem. Recordings were made in the segments T7, L2, and L5 using calcium imaging from individual axial MNs in the medial motor column (MMC) and hindlimb MNs in lateral motor column (LMC). The MN activities were analyzed during both the rhythmic and the tonic components of LLA, the tonic component being used as a readout of generalized increase in excitability in spinal locomotor networks. The most salient effect of brain stem removal was an increase in locomotor rhythm frequency and a concomitant reduction in burst durations in both MMC and LMC MNs. The lack of effect on the tonic component of LLA indicated specificity of action during the rhythmic component. Cooling-induced silencing of the brain stem reproduced the increase in rhythm frequency and accompanying decrease in burst durations in L2 MMC and LMC, suggesting a dependency on brain stem neuron activity. The work supports the idea that the brain stem locomotor circuits are operational already at birth and further suggests an important role in modulating trunk activity. The brain stem may influence the axial and hindlimb spinal locomotor rhythm generating circuits by extending their range of operation. This may represent a critical step of locomotor development when learning how to walk in different conditions and environments is a major endeavor.
Author Notes
  • Present Address: Céline Jean-Xavier, Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
Keywords
Research Categories
  • Health Sciences, General
  • Biology, Physiology

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