ZFIN ID: ZDB-PUB-081218-3
Determining the function of zebrafish epithalamic asymmetry
Facchin, L., Burgess, H.A., Siddiqi, M., Granato, M., and Halpern, M.E.
Date: 2009
Source: Philosophical transactions of the Royal Society of London. Series B, Biological sciences   364(1519): 1021-1032 (Journal)
Registered Authors: Burgess, Harold, Facchin, Lucilla, Granato, Michael, Halpern, Marnie E.
Keywords: habenula, brain asymmetry, behaviour
MeSH Terms:
  • Animals
  • Brain/anatomy & histology
  • Brain/physiology*
  • Epithalamus/anatomy & histology
  • Epithalamus/physiology*
  • Functional Laterality/genetics
  • Functional Laterality/physiology*
  • Genes, Reporter
  • Larva/anatomy & histology
  • Larva/physiology
  • Motor Activity/physiology
  • Signal Transduction/physiology
  • Viscera/anatomy & histology
  • Viscera/physiology
  • Zebrafish/genetics
  • Zebrafish/physiology*
PubMed: 19064346 Full text @ Phil. Trans. Roy. Soc. Lond., Series B
ABSTRACT
As in many fishes, amphibians and reptiles, the epithalamus of the zebrafish, Danio rerio, develops with pronounced left-right (L-R) asymmetry. For example, in more than 95 per cent of zebrafish larvae, the parapineal, an accessory to the pineal organ, forms on the left side of the brain and the adjacent left habenular nucleus is larger than the right. Disruption of Nodal signalling affects this bias, producing equal numbers of larvae with the parapineal on the left or the right side and corresponding habenular reversals. Pre-selection of live larvae using fluorescent transgenic reporters provides a useful substrate for studying the effects of neuroanatomical asymmetry on behaviour. Previous studies had suggested that epithalamic directionality is correlated with lateralized behaviours such as L-R eye preference. We find that the randomization of epithalamic asymmetry, through perturbation of the nodal-related gene southpaw, does not alter a variety of motor behaviours, including responses to lateralized stimuli. However, we discovered significant deficits in swimming initiation and in the total distance navigated by larvae with parapineal reversals. We discuss these findings with respect to previous studies and recent work linking the habenular region with control of the motivation/reward pathway of the vertebrate brain.
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