Rostro-caudal inhibition of hindlimb movements in the spinal cord of mice

PLoS One. 2014 Jun 25;9(6):e100865. doi: 10.1371/journal.pone.0100865. eCollection 2014.

Abstract

Inhibitory neurons in the adult mammalian spinal cord are known to locally modulate afferent feedback--from muscle proprioceptors and from skin receptors--to pattern motor activity for locomotion and postural control. Here, using optogenetic tools, we explored how the same population of inhibitory interneurons globally affects hindlimb movements in the spinal cord of both anesthetized and freely moving mice. Activation of inhibitory interneurons up to the middle/lower spinal cord i.e. T8-T9, were able to completely and globally suppress all ipsilateral hindlimb movements. Furthermore, the same population of interneurons--which inhibited movements--did not significantly change the sensory and proprioceptive information from the affected limbs to the cortex. These results suggest a rostro-caudal organization of inhibition in the spinal cord motor output without modulation of ascending sensory pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Afferent Pathways
  • Animals
  • Cells, Cultured
  • Channelrhodopsins
  • Electric Stimulation
  • Hindlimb / physiology*
  • Immunoenzyme Techniques
  • Interneurons / cytology
  • Interneurons / physiology*
  • Locomotion / physiology*
  • Mice
  • Nerve Net / physiology*
  • Neural Inhibition / physiology*
  • Spinal Cord / cytology
  • Spinal Cord / physiology*
  • Synaptic Transmission
  • Vesicular Inhibitory Amino Acid Transport Proteins / physiology

Substances

  • Channelrhodopsins
  • Vesicular Inhibitory Amino Acid Transport Proteins
  • Viaat protein, mouse

Grant support

V.C. is supported by the Human Frontier Science Program fellowship (LT001234/2011-L). Contributing grants include NSF IIS-0904594. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.