Neuroanatomy of the Zebrafish Brain

The zebrafish, Danio (Brachydanio) rerio, is considered one of the major model systems for the study of nervous system development and function at molecular, cellular and systems level. This is due in large part to the extensive and ongoing maturation of sophisticated genetic manipulation and mutant generation techniques. Although considerable knowledge concerning the embryonic development of the central nervous system in this animal has been gained in recent years, there is a lack of information concerning the structural organization of the adult brain. This work therefore aims at providing a neuroanatomical overview of the zebrafish brain, and identifies the major subdivisions, nuclei and tracts within the adult brain, based mainly on a comparison with the well-known brain of the closely related goldfish, Carassius auratus. In the course of this investigation, more than 30 complete series of 12mu m Bodian stains cross, sagittal and horizontal sections were produced and analyzed. Here, a selection of sections out of the three best series is presented. The discussion provides a source of information about the major subdivisions and eventual fibre connections within the zebrafish brain, as well as remarks about their functional significance.