title: Refining the Ciona intestinalis model of central nervous system regeneration.
abstract: BACKGROUND
  New, practical models of central nervous system regeneration are required and should provide molecular tools and resources. We focus here on the tunicate Ciona intestinalis, which has the capacity to regenerate nerves and a complete adult central nervous system, a capacity unusual in the chordate phylum. We investigated the timing and sequence of events during nervous system regeneration in this organism.
  
  
  RESULTS
  We developed techniques for reproducible ablations and for imaging live cellular events in tissue explants. Based on live observations of more than 100 regenerating animals, we subdivided the regeneration process into four stages. Regeneration was functional, as shown by the sequential recovery of reflexes that established new criteria for defining regeneration rates. We used transgenic animals and labeled nucleotide analogs to describe in detail the early cellular events at the tip of the regenerating nerves and the first appearance of the new adult ganglion anlage.
  
  
  CONCLUSIONS
  The rate of regeneration was found to be negatively correlated with adult size. New neural structures were derived from the anterior and posterior nerve endings. A blastemal structure was implicated in the formation of new neural cells. This work demonstrates that Ciona intestinalis is as a useful system for studies on regeneration of the brain, brain-associated organs and nerves.
authors.affiliation: Department of Marine Ecology, Göteborg University, Fiskebäckskil, Sweden. carl.dahlberg@marecol.gu.se
authors.forename: Carl
authors.initials: C
authors.lastname: Dahlberg
authors.forename: Hélène
authors.initials: H
authors.lastname: Auger
authors.forename: Sam
authors.initials: S
authors.lastname: Dupont
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sasakura
authors.forename: Mike
authors.initials: M
authors.lastname: Thorndyke
authors.forename: Jean-Stéphane
authors.initials: JS
authors.lastname: Joly
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001522:Behavior, Animal; D002490:Central Nervous System / Q000033:anatomy & histology / Q000473:pathology / Q000502:physiology*; D002938:Ciona intestinalis / Q000033:anatomy & histology / Q000502:physiology; D015870:Gene Expression; D008954:Models, Biological; D009416:Nerve Regeneration / Q000502:physiology*; D011897:Random Allocation; D012018:Reflex; D019076:Transgenes