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Embryonic development of the pars intercerebralis/central complex of the grasshopper

Authors :
J. L. D. Williams
George Boyan
Source :
Development Genes and Evolution. 207:317-329
Publication Year :
1997
Publisher :
Springer Science and Business Media LLC, 1997.

Abstract

We have studied the embryonic development of the pars intercerebralis/central complex in the brain of the grasshopper using immunocytochemical and histochemical techniques. Expression of the cell-surface antigen lachesin reveals that the neuroblasts of the pars intercerebralis first differentiate from the neuroectoderm at around 26% of embryogenesis. Differentiation of medial and lateral neuroblasts occurs first. By the 28% stage a more or less uniform sheet of 20 neuroblasts has formed. As a result of both cell proliferation and cell translocation, the pars intercerebralis proliferative cluster in each hemisphere expands so that at 30% the most medial neuroblasts lie apposed at the midline. We followed the further development of the pars intercerebralis of each brain hemisphere using bromo-deoxy-uridine incorporation and osmium-ethyl-gallate staining. Within the pars intercerebralis itself, the neuroblasts redistribute into discrete subsets. The neuroblasts of each subset generate clusters of progeny which extend in a stereotypic, subset-specific direction in the brain. We have used this feature to identify one subset of four neuroblasts as being the likely progenitor cells for four clusters of embryonic neurons (W, X, Y, Z) which develop at around 55% of embryogenesis. We show that these progeny project axons via four discrete fascicles (w, x, y, z) into the embryonic central complex. At the single cell level, Golgi impregnation reveals that the axons from these neighbouring cell clusters remain discrete, and those from the same cluster tightly fasciculated, as they project into the central complex, consistent with a modular organization for this brain region.

Details

ISSN :
1432041X and 0949944X
Volume :
207
Database :
OpenAIRE
Journal :
Development Genes and Evolution
Accession number :
edsair.doi.dedup.....8755511c6514d4cb29360a5aa7d12639
Full Text :
https://doi.org/10.1007/s004270050119