Segment-related, mosaic neurogenetic pattern in the forebrain and mesencephalon of early chick embryos: I. Topography of ache-positive neuroblasts up to stage HH18
Version of Record online: 9 OCT 2004
Copyright © 1987 Alan R. Liss, Inc.
Journal of Comparative Neurology
Volume 266, Issue 2, pages 247–268, 8 December 1987
How to Cite
Puelles, L., Amat, J. A. and Martinez-de-la-Torre, M. (1987), Segment-related, mosaic neurogenetic pattern in the forebrain and mesencephalon of early chick embryos: I. Topography of ache-positive neuroblasts up to stage HH18. J. Comp. Neurol., 266: 247–268. doi: 10.1002/cne.902660210
- Issue online: 9 OCT 2004
- Version of Record online: 9 OCT 2004
- Manuscript Accepted: 2 JUL 1987
- migration area
Histochemical mapping of AChE-positive neuroblasts in sectioned and whole-mounted preparations of the chick embryo mesencephalon and prosencephalon allows a correlation of early neural tube morphogenesis (segmentation, longitudinal compartmentation) with the heterochronic pattern of neurogenesis. One significant finding is that the initial appearance of neuroblasts in the forebrain does not follow neuromeric segmentation, but evolves in parallel with it. Early neuroblasts appear as separate, distinct groups within specific matrix territories at the center of the transverse neuromeric segments. Neighbouring segments display different spatiotemporal patterns of neurogenesis. Overall gradients of differentiation in the rostrocaudal and ventrodorsal directions are absent, whereas a clear-cut segment-related, mosaic pattern becomes evident. Notwithstanding this, gross regularities of heterochrony in the neurogenetic behavior of the different segments lead to a definition of elemental longitudinal compartments of the forebrain and mesencephalon (floor, paramedian, basal, and alar regions) on the basis of precocious differentiation of the basal region and retarded differentiation of the paramedian and alar regions.