Spinal microcircuits comprising dI3 interneurons are necessary for motor functional recovery following spinal cord transection
The spinal cord has the capacity to coordinate motor activities such as locomotion. Following spinal transection, functional activity can be regained, to a degree, following motor training. To identify microcircuits involved in this recovery, we studied a population of mouse spinal interneurons known to receive direct afferent inputs and project to intermediate and ventral regions of the spinal cord. We demonstrate that while dI3 interneurons are not necessary for normal locomotor activity, locomotor circuits rhythmically inhibit them and dI3 interneurons can activate these circuits. Removing dI3 interneurons from spinal microcircuits by eliminating their synaptic transmission left locomotion more or less unchanged, but abolished functional recovery, indicating that dI3 interneurons are a necessary cellular substrate for motor system plasticity following transection. We suggest that dI3 interneurons compare inputs from locomotor circuits with sensory afferent inputs to compute sensory prediction errors that then modify locomotor circuits to effect motor recovery.
Article and author information
Canadian Institutes of Health Research (Operating grant, FRN 79413)
- Robert M Brownstone
Nova Scotia Health Research Foundation (Post-doctoral fellowship)
- Tuan V Bui
Natural Sciences and Engineering Research Council of Canada (Discovery grant, RGPIN-2015-06403)
- Tuan V Bui
Canada Research Chairs (Research Chair)
- Robert M Brownstone
Canadian Institutes of Health Research (Fellowship)
- Tuan V Bui
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: All animal procedures were approved by the University Committee on Laboratory Animals of Dalhousie University (protocol 13-143) and conform to the guidelines put forth by the Canadian Council for Animal Care.
- Ole Kiehn, Karolinska Institutet, Sweden
- Received: September 21, 2016
- Accepted: December 12, 2016
- Accepted Manuscript published: December 15, 2016 (version 1)
- Accepted Manuscript updated: December 22, 2016 (version 2)
- Version of Record published: January 6, 2017 (version 3)
© 2016, Bui et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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