About this item:

52 Views | 70 Downloads

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

Funding acquisition: M-CP; Conceptualization: M-CP and CJ-X; Supervision: M-CP; Methodology: CJ-X and M-CP; Experiments: CJ-X; Analyses: CJ-X and M-CP; Interpretation: M-CP and CJ-X;

Writing of original draft: M-CP; Editing and approval of final version approval: M-CP and CJ-X.

Ms. Renee Shaw for technical support, Drs Yoav Mor and Aharon Lev-Tov providing the SpinalCore software, and Dr. Morten Raastad for constructive comments on an earlier draft of this manuscript.

Conflict of interest statement: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Subjects:

Research Funding:

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.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Neurosciences
  • Neurosciences & Neurology
  • motor command
  • subcortical
  • reticulospinal
  • vestibulospinal
  • CPG
  • trunk-hindlimb coordination
  • CENTRAL PATTERN GENERATOR
  • EPAXIAL MUSCLE FUNCTION
  • FICTIVE LOCOMOTION
  • RETICULOSPINAL NEURONS
  • IN-VITRO
  • PHASIC MODULATION
  • XENOPUS-LAEVIS
  • NEWBORN RAT
  • SPATIOTEMPORAL ORGANIZATION
  • ADULT DECEREBRATE

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

Tools:

Journal Title:

Frontiers in Neuroscience

Volume:

Volume 12, Number FEB

Publisher:

, Pages 53-53

Type of Work:

Article | Final Publisher PDF

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.

Copyright information:

© 2018 Jean-Xavier and Perreault.

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
Export to EndNote