ZFIN ID: ZDB-PUB-091101-27
Spinal interneurons differentiate sequentially from those driving the fastest swimming movements in larval zebrafish to those driving the slowest ones
McLean, D.L., and Fetcho, J.R.
Date: 2009
Source: The Journal of neuroscience : the official journal of the Society for Neuroscience   29(43): 13566-13577 (Journal)
Registered Authors: Fetcho, Joseph R.
Keywords: none
MeSH Terms:
  • Action Potentials
  • Animals
  • Animals, Genetically Modified
  • Biomechanical Phenomena
  • Cell Size
  • Interneurons/physiology*
  • Luminescent Proteins/genetics
  • Luminescent Proteins/metabolism
  • Microscopy, Confocal
  • Motor Activity/physiology
  • Motor Neurons/physiology
  • Neural Pathways/embryology
  • Neural Pathways/growth & development
  • Neural Pathways/physiology
  • Neurogenesis
  • Patch-Clamp Techniques
  • Spinal Cord/embryology
  • Spinal Cord/growth & development*
  • Spinal Cord/physiology*
  • Swimming/physiology*
  • Time Factors
  • Zebrafish/physiology*
PubMed: 19864569 Full text @ J. Neurosci.
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ABSTRACT
Studies of neuronal networks have revealed few general principles that link patterns of development with later functional roles. While investigating the neural control of movements, we recently discovered a topographic map in the spinal cord of larval zebrafish that relates the position of motoneurons and interneurons to their order of recruitment during swimming. Here, we show that the map reflects an orderly pattern of differentiation of neurons driving different movements. First, we use high-speed filming to show that large-amplitude swimming movements with bending along much of the body appear first, with smaller, regional swimming movements emerging later. Next, using whole-cell patch recordings, we demonstrate that the excitatory circuits that drive large-amplitude, fast swimming movements at larval stages are present and functional early on in embryos. Finally, we systematically assess the orderly emergence of spinal circuits according to swimming speed using transgenic fish expressing the photoconvertible protein Kaede to track neuronal differentiation in vivo. We conclude that a simple principle governs the development of spinal networks in which the neurons driving the fastest, most powerful swimming in larvae develop first with ones that drive increasingly weaker and slower larval movements layered on over time. Because the neurons are arranged by time of differentiation in the spinal cord, the result is a topographic map that represents the speed/strength of movements at which neurons are recruited and the temporal emergence of networks. This pattern may represent a general feature of neuronal network development throughout the brain and spinal cord.
ADDITIONAL INFORMATION