Decoding the rules of recruitment of excitatory interneurons in the adult zebrafish locomotor network
- Authors
- Ausborn, J., Mahmood, R., and El Manira, A.
- ID
- ZDB-PUB-121220-20
- Date
- 2012
- Source
- Proceedings of the National Academy of Sciences of the United States of America 109(52): E3631-3639 (Journal)
- Registered Authors
- Keywords
- central pattern generator, synaptic transmission, Chx10
- MeSH Terms
-
- Aging/physiology*
- Animals
- Interneurons/physiology*
- Locomotion/physiology*
- Motor Neurons/physiology
- Nerve Net/physiology*
- Neural Inhibition/physiology
- Recruitment, Neurophysiological*
- Swimming/physiology
- Synapses/physiology
- Time Factors
- Zebrafish/physiology*
- PubMed
- 23236181 Full text @ Proc. Natl. Acad. Sci. USA
Neural networks in the spinal cord transform signals from the brain into coordinated locomotor movements. An optimal adjustment of the speed of locomotion entails a precise order of recruitment of interneurons underlying excitation within these networks. However, the mechanisms encoding the recruitment threshold of excitatory interneurons have remained unclear. Here we show, using a juvenile/adult zebrafish preparation, that excitatory V2a interneurons are incrementally recruited with increased swimming frequency. The order of recruitment is not imprinted by the topography or the input resistance of the V2a interneurons. Rather, it is determined by scaling the effect of excitatory synaptic currents by the input resistance. We also show that the locomotor networks are composed of multiple microcircuits encompassing subsets of V2a interneurons and motoneurons that are recruited in a continuum with increased swimming speeds. Thus, our results provide insights into the organization and mechanisms determining the recruitment of spinal microcircuits to ensure optimal execution of locomotor movements.