Journal article
Neuronal activity in the isolated mouse spinal cord during spontaneous deletions in fictive locomotion: insights into locomotor central pattern generator organization
The Journal of physiology, v 590(19), pp 4735-4759
01 Oct 2012
PMID: 22869012
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
We explored the organization of the spinal central pattern generator (CPG) for locomotion by analysing the activity of spinal interneurons and motoneurons during spontaneous deletions occurring during fictive locomotion in the isolated neonatal mouse spinal cord, following earlier work on locomotor deletions in the cat. In the isolated mouse spinal cord, most spontaneous deletions were non-resetting, with rhythmic activity resuming after an integer number of cycles. Flexor and extensor deletions showed marked asymmetry: flexor deletions were accompanied by sustained ipsilateral extensor activity, whereas rhythmic flexor bursting was not perturbed during extensor deletions. Rhythmic activity on one side of the cord was not perturbed during non-resetting spontaneous deletions on the other side, and these deletions could occur with no input from the other side of the cord. These results suggest that the locomotor CPG has a two-level organization with rhythm-generating (RG) and pattern-forming (PF) networks, in which only the flexor RG network is intrinsically rhythmic. To further explore the neuronal organization of the CPG, we monitored activity of motoneurons and selected identified interneurons during spontaneous non-resetting deletions. Motoneurons lost rhythmic synaptic drive during ipsilateral deletions. Flexor-related commissural interneurons continued to fire rhythmically during non-resetting ipsilateral flexor deletions. Deletion analysis revealed two classes of rhythmic V2a interneurons. Type I V2a interneurons retained rhythmic synaptic drive and firing during ipsilateral motor deletions, while type IIV2a interneurons lost rhythmic synaptic input and fell silent during deletions. This suggests that the type I neurons are components of the RG, whereas the type II neurons are components of the PF network.We propose a computational model of the spinal locomotor CPG that reproduces our experimental results. The results may provide novel insights into the organization of spinal locomotor networks.
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Details
- Title
- Neuronal activity in the isolated mouse spinal cord during spontaneous deletions in fictive locomotion: insights into locomotor central pattern generator organization
- Creators
- Guisheng Zhong - Department of Neurobiology and Behavior, Cornell University, W 159 Seeley G. Mudd Hall, Ithaca, NY 14853, USANatalia A ShevtsovaIlya A RybakRonald M Harris-Warrick
- Publication Details
- The Journal of physiology, v 590(19), pp 4735-4759
- Publisher
- England
- Grant note
- R01 NS017323 / NINDS NIH HHS R37 NS017323 / NINDS NIH HHS NS057599 / NINDS NIH HHS NS17323 / NINDS NIH HHS R01 NS057599 / NINDS NIH HHS NS04884 / NINDS NIH HHS R56 NS017323 / NINDS NIH HHS
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Neurobiology and Anatomy
- Web of Science ID
- WOS:000309401100009
- Scopus ID
- 2-s2.0-84866858970
- Other Identifier
- 991014877785704721
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Neurosciences
- Physiology