QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

This Article Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Silver, J. Articles by Rutishauser, U. Search for Related Content PubMed PubMed Citation Articles by Silver, J. Articles by Rutishauser, U.

 Previous Article

Journal of Neuroscience, Vol 7, 2264-2272, Copyright © 1987 by Society for Neuroscience

ARTICLE

Axon pathway boundaries in the developing brain. I. Cellular and molecular determinants that separate the optic and olfactory projections

J Silver, M Poston and U Rutishauser

When optic fibers first approach the chiasmatic region of the diencephalon in the chick embryo on days 3 and 4 (E3-4), they rarely grow rostrally into the olfactory region of the telencephalon. Conversely, olfactory tract axons grow as far as, but never cross the diencephalic/telencephalic (D/T) boundary to enter the optic chiasm. In this study, a region of specialized neuroepithelium, originally named the "knot" in mouse by Silver (1984), has been identified at the D/T border of chick embryos. At pre-axonal stages, the presumptive knot region undergoes a cataclysmic cell death, with concomitant phagocytosis of necrotic debris by the remaining cells. When fibers subsequently appear in the chiasm and olfactory tracts, the knot consists of a very dense, interwoven cluster of non-neuronal cells that lack marginal radial processes, and whose cell bodies directly abut the glial limiting membrane. Thus, the morphology of the knot is in sharp contrast to the cell body-free marginal zone and endfoot regions along which axons tend to grow. In addition, we found that the neural cell adhesion molecule (N-CAM), which is expressed on neuroepithelial cell processes within the central optic and olfactory pathways, is not present on cells in the knot region during periods of axon growth. These results suggest that the knot, through its elimination of the marginal zone processes, absence of large extracellular spaces, and relative absence of adhesion molecules, functions as an axon-refractory barrier that effectively separates the optic and olfactory projections.

This article has been cited by other articles:

				L. Gao and R. H. Miller Specification of optic nerve oligodendrocyte precursors by retinal ganglion cell axons. J. Neurosci., July 19, 2006; 26(29): 7619 - 7628. [Abstract] [Full Text] [PDF]

				H. Ichijo and I. Kawabata Roles of the Telencephalic Cells and their Chondroitin Sulfate Proteoglycans in Delimiting an Anterior Border of the Retinal Pathway J. Neurosci., December 1, 2001; 21(23): 9304 - 9314. [Abstract] [Full Text] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help