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Previous Article | Next Article
The Journal of Neuroscience, November 1, 2000, 20(21):8021-8030
Cell Migration and Aggregation in the Developing Telencephalon: Pulse-Labeling Chick Embryos with Bromodeoxyuridine
Georg F. Striedter and Brian P. Keefer Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California at Irvine, Irvine, California 92697-4550
Previous studies had concluded that the avian telencephalon develops according to an outside-in schedule of neurogenesis, with relatively little migration of young neuroblasts past older cells. These previous studies had, however, been based on the "cumulative labeling" method, which is less accurate than the "pulse-labeling" method typically used in mammals. In the present study, we pulse-labeled chick embryos by injecting low doses of the thymidine analog bromodeoxyuridine (BrdU) directly into the circulatory system of chick embryos at 6 d of incubation. The brains of these embryos were then examined for anti-BrdU-labeled cells at postinjection survival times from 30 min to 10 d. Comparisons across different survival times, as well as with cases in which BrdU was injected on day 7, suggested that our effective pulse duration is <24 hr. This was confirmed by injecting tritiated thymidine 24 hr after the BrdU and seeing no double-labeled cells. Several deviations from the previously reported pattern of telencephalic neurogenesis were also noted. Most importantly, the cells born on day 6 in the avian Wulst, the likely homolog of mammalian neocortex, end up homogeneously distributed throughout the Wulst, which suggests that many of them are migrating past older cells. Furthermore, the cells born on day 6 in the ventral hyperstriatum and dorsal neostriatum gradually (over the course of 2-3 d) aggregate into distinct multicellular clusters, which suggests that isochronic cells in these regions adhere preferentially to one another. Finally, the data reveal a proliferative subventricular zone similar to that observed in the ganglionic eminences of mammalian embryos.
Key words: outside-in; inside-out; birth dating; thymidine; forebrain; birds
Copyright © 2000 Society for Neuroscience 0270-6474/00/20218021-10$05.00/0
This article has been cited by other articles:
G. F Striedter and C. J Charvet
Telencephalon enlargement by the convergent evolution of expanded subventricular zones
Biol Lett, February 23, 2009; 5(1): 134 - 137.
[Abstract] [Full Text] [PDF]
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