Cytoarchitecture of a Cichlid Fish Telencephalon

Abstract

Although the telencephalon of ray-finned fishes has garnered considerable attention from comparative neuroanatomists, detailed descriptions of telencephalic organization are available for only a few species. This necessarily limits our understanding of telencephalic evolution, particularly in light of the extraordinary diversity of ray-finned fishes. Thus, we have charted the cyctoarchitecture of the telencephalon of the African cichlid fish, Astatotilapia (Haplochromis) burtoni. We examined tissue sectioned in the transverse plane, and categorized cell groups based on size, shape, and staining intensity of cells, the density and distribution of cells, cell-poor zones, and relationship of cell groups to the anterior commissure and external sulci. In addition, to facilitate visualization of the transitions among cell groups, we aligned and animated a series of 100 sequential brain sections. We found that the A. burtoni telencephalon was similar to other percomorphs in being highly elaborated with many distinct cell groups. In the pallium, Dm, Dl, and Dc had a large number of cell groups, whereas Dd and Dp were more uniform. Although we recognized many similarities between the pallium of A. burtoni and other teleosts, we also recognized two cell groups (Dl-g and Dm-2) that might represent specializations of cichlids. We found that the subpallium had a similar organization to that of other ray-finned fishes.

What do fish make of mirror images?

“…A frozen stage (Physitemp) viewed through a dissection microscope was used for microdissection, performed with a modified 27G needle with an internal diameter of 190 mm following an established protocol (Korzan et al 2000). Brain atlases from A. burtoni (Fernald & Shelton 1985;Burmeister et al 2009) and from other fish species (e.g. Reiner & Northcutt 1992) were used to target the Cce, Dl, Dm and POA and for all of these brain areas, the entire nucleus was collected and treated identically (e.g.…”

Female genomic response to mate information

“…An established protocol was followed to microdissect specific brain regions from the 300-μm thick slices (17,(42)(43)(44). Brain atlases from A. burtoni (45,46) and other fishes (47)(48)(49) were used to target the nuclei of the SBN: PAG, AH, Vm, Dm, POA, and LS.…”

Do Teleost Fishes Possess a Homolog of Mammalian Isocortex?

“…Furthermore, it is very important that similar cell lineage studies be performed in centrarchid and cichlid teleosts, where the pallia are characterized by large cell populations that have been identified as multiple divisions of Dc [Northcutt and Braford, 1980;Demski and Beaver, 2001;Pepels et al, 2002;Burmeister et al, 2009] before the condition in teleosts can be said to be established. It is possible that the cell population recognized as Dc in cyprinids, such as the zebrafish, arises only from the dorsal germinative zone, whereas the Dc populations in more derived teleosts arise from multiple germinative zones.…”