Early development of functional spatial maps in the zebrafish olfactory bulb

Li, J., Mack, J.A., Souren, M., Yaksi, E., Higashijima, S., Mione, M., Fetcho, J.R., and Friedrich, R.W.
The Journal of neuroscience : the official journal of the Society for Neuroscience   25(24): 5784-95 (Journal)
Registered Authors
Fetcho, Joseph R., Friedrich, Rainer, Higashijima, Shin-ichi, Mack, Julia, Mione, Marina, Yaksi, Emre
olfactory bulb; sensory map; neural development; in vivo imaging; transgenic calcium indicator; zebrafish
MeSH Terms
  • Animals
  • Animals, Genetically Modified
  • Green Fluorescent Proteins/analysis
  • Green Fluorescent Proteins/genetics
  • Odorants
  • Olfactory Bulb/anatomy & histology*
  • Olfactory Bulb/growth & development
  • Olfactory Bulb/physiology*
  • Smell
  • Zebrafish
15958745 Full text @ J. Neurosci.
In the adult olfactory bulb (OB), particular chemical classes of odorants preferentially activate glomeruli within loosely defined regions, resulting in a coarse and fractured "chemotopic" map. In zebrafish, amino acids and bile acids predominantly stimulate glomeruli in the lateral and medial OB, respectively. We studied the development of these spatial response maps in zebrafish. At 3 d postfertilization (dpf), the OB contained protoglomerular structures that became refined and more numerous during subsequent days. In a transgenic zebrafish line expressing the Ca2+ indicator protein inverse pericam, mainly in mitral cells, odor responses in the OB were first detected at 2.5-3 dpf. Already at this stage, amino acids and bile acids evoked activity predominantly in the lateral and medial OB, respectively. Two-photon Ca2+ imaging using a synthetic indicator was used to reconstruct activity patterns at higher resolution in three dimensions. Responses to amino acids and bile acids were detected predominantly in the lateral and medial OB, respectively, with little overlap. Between 2.5 and 6 dpf, the number of odor-responsive units increased, but the overall spatial organization of activity persisted. Hence, a coarse spatial organization of functional activity maps is established very early during OB development when glomeruli are not yet differentiated. This spatial organization is maintained during development and growth of neuronal circuits and may have important functions for odor processing in larvae, for the differentiation of glomeruli, and for the refinement of activity maps at later developmental stages.
Genes / Markers
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Engineered Foreign Genes