Patterns of neurogenesis in the midbrain of embryonic lobsters differ from proliferation in the insect and the crustacean ventral nerve cord.
Neurogenesis persists throughout life in the olfactory pathway of many decapod crustaceans. However, the relationships between precursor cells and the temporal characteristics of mitotic events in these midbrain regions have not been examined. We have conducted studies aimed at characterizing the sequence of proliferative events that leads to the production of new deutocerebral projection neurons in embryos of the American lobster, Homarus americanus. In vivo bromodeoxyuridine (BrdU) labeling patterns show that three distinct cell types are involved in neurogenesis in this region. Quantitative and temporal analyses suggest that the clearing time for BrdU is 2-3 days in lobster embryos, and that the sequence of proliferative events in the midbrain is significantly different from the stereotypical pattern for the generation of neurons in the ventral nerve cord ganglia of insects and crustaceans. The unusual pattern of proliferation in the crustacean midbrain may be related to the persistence of neurogenesis throughout life in these regions.
D000818:Animals; D002452:Cell Count; D002454:Cell Differentiation; D002455:Cell Division; D004625:Embryo, Nonmammalian / Q000166:cytology; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000196:embryology; D008636:Mesencephalon / Q000166:cytology / Q000196:embryology*; D008121:Nephropidae / Q000166:cytology / Q000196:embryology*; D009474:Neurons / Q000166:cytology*; D009833:Olfactory Pathways / Q000166:cytology / Q000196:embryology