Post-hatching brain morphogenesis and cell proliferation in the pulse-type mormyrid Mormyrus rume proboscirostris.

Publication date: Available online 23 November 2016 Source:Journal of Physiology-Paris Author(s): Milka Radmilovich, Isabel Barreiro, Leticia Iribarne, Kirsty Grant, Frank Kirschbaum, María E. Castelló The anatomical organization of African Mormyrids’ brain is a clear example of departure from the average brain morphotype in teleosts, probably related to functional specialization associated to electrosensory processing and sensory-motor coordination. The brain of Mormyrids is characterized by a well-developed rhombencephalic electrosensory lobe interconnected with relatively large mesencephalic torus semicircularis and optic tectum, and a huge and complex cerebellum. This unique morphology might imply cell addition from extraventricular proliferation zones up to late developmental stages. Here we studied the ontogeny of these brain regions in Mormyrus rume proboscirostris from embryonic to adult stages by classical histological techniques and 3D reconstruction, and analyzed the spatial-temporal distribution of proliferating cells, using pulse type BrdU labeling. Brain morphogenesis and maturation progressed in rostral-caudal direction, from 4 day old free embryos, through larvae, to juveniles whose brain almost attained adult morphological complexity. The change in the relative size of the telencephalon, mesencephalic and rhombencephalic brain regions suggest a developmental shift in the relative importance of visual and electrosensory modalities. In free embryos,...
Source: Journal of Physiology Paris - Category: Physiology Source Type: research