PUBLICATION

Spinal V2b neurons reveal a role for ipsilateral inhibition in speed control

Authors
Callahan, R.A., Roberts, R., Sengupta, M., Kimura, Y., Higashijima, S.I., Bagnall, M.W.
ID
ZDB-PUB-190730-8
Date
2019
Source
eLIFE   8: (Journal)
Registered Authors
Bagnall, Martha, Higashijima, Shin-ichi, Roberts, Richard, Sengupta, Mohini
Keywords
neuroscience, zebrafish
MeSH Terms
  • Animals
  • Interneurons/physiology*
  • Motion
  • Motor Neurons/physiology*
  • Muscle Contraction
  • Spinal Cord/cytology*
  • Zebrafish
PubMed
31355747 Full text @ Elife
Abstract
The spinal cord contains a diverse array of interneurons that govern motor output. Traditionally, models of spinal circuits have emphasized the role of inhibition in enforcing reciprocal alternation between left and right sides or flexors and extensors. However, recent work has shown that inhibition also increases coincident with excitation during contraction. Here, using larval zebrafish, we investigate the V2b (Gata3+) class of neurons, which contribute to flexor-extensor alternation but are otherwise poorly understood. Using newly generated transgenic lines we define two stable subclasses with distinct neurotransmitter and morphological properties. These V2b subclasses synapse directly onto motor neurons with differential targeting to speed-specific circuits. In vivo, optogenetic manipulation of V2b activity modulates locomotor frequency: suppressing V2b neurons elicits faster locomotion, whereas activating V2b neurons slows locomotion. We conclude that V2b neurons serve as a brake on axial motor circuits. Together, these results indicate a role for ipsilateral inhibition in speed control.
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