| Relationship of retinotopic ordering of axons in the optic pathway to the formation of visual maps in central targets. | |
| | |
MedLine Citation:
|
PMID: 1856329 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
We examined in rats the relationship between the ordering of retinal axons in the optic pathway and the formation of a retinotopically organized projection to their primary target, the contralateral superior colliculus (SC). We have previously found that axons labeled by focal injections of 1,1'-dioctadecyl 3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) made in temporal or nasal retina of perinatal rats commonly mistarget along the medial-lateral and rostral-caudal axes of the SC. By postnatal day (P) 11-12, the retinocollicular projection attains an adult-like topography. Incorrectly targeted axons or axon segments are removed; axons that persist terminate in the topographically appropriate part of the SC (Simon and O'Leary: Dev Biol 137:125, 1990). In the present study, we made similar DiI injections, covering less than 2% of the retinal area, in peripheral temporal, nasal, superior, or inferior retina, in rats of two age groups, embryonic day (E) 21 to P (postnatal day) 2 and P11-P17. Whole mounts of retina, optic nerve and tract, and SC, and cross sections of the optic nerve, were examined. In E21-P2 rats, retinal axons labeled from each retinal site are diffusely distributed in the SC, and poorly ordered in the optic pathway. In retina, labeled axons travel in fascicles directly from the injection site to the optic disc, but neighbor relationships begin to degrade as fascicles split and mix. Retinotopic order is virtually lost in the optic nerve; axons labeled from each injection site disperse throughout its cross-sectional area, but the labeled axons tend to be concentrated toward a specific half of the nerve depending upon their retinal origin. This slight tendency toward retinotopic order increases in the optic tract, but axons are still poorly ordered as they leave the tract and enter the SC. Targeting errors along the medial-lateral axis of the SC, but apparently not along its rostral-caudal axis, are related to the positioning of axons across the width of the optic tract. In P11-P17 rats, axons labeled from each injection site arborize only in a small, topographically correct part of the SC. However, the distributions of labeled retinal axons observed in whole mounts of the retina and optic pathway have a degree of disorder similar to those in E21-P2 rats. Further, the scatter of labeled axons in optic nerve cross sections is comparable in both age groups. Therefore, the emergence of topographic order in the retinocollicular projection is not accompanied by an emergence of a retinotopic ordering of axons in the optic nerve.(ABSTRACT TRUNCATED AT 400 WORDS) |
| | |
Authors:
|
D K Simon; D D O'Leary |
Related Documents
:
|
965509 - The cat optic nerve: fibre total count and diameter spectrum. 11140369 - Modulation of taurine uptake in the goldfish retina and axonal transport to the tectum.... 10751179 - The conditional medaka mutation eyeless uncouples patterning and morphogenesis of the eye. 3265109 - In vitro regeneration of adult rat ganglion cell axons from retinal explants. 3198799 - Axons added to the regenerated visual pathway of goldfish establish a normal fiber topo... 2912799 - Expression of acetylcholinesterase during visual system development in drosophila. 3928459 - Myelofibrosis, autoimmune haemolytic anaemia and tn-polyagglutinability. 3258549 - Organization of lymphocyte plasma membrane. surface protein-membrane matrix interaction... 17241099 - Irreversible electroporation: a new ablation modality--clinical implications. |
Publication Detail:
|
Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
|
Title: The Journal of comparative neurology Volume: 307 ISSN: 0021-9967 ISO Abbreviation: J. Comp. Neurol. Publication Date: 1991 May |
Date Detail:
|
Created Date: 1991-08-28 Completed Date: 1991-08-28 Revised Date: 2008-11-21 |
Medline Journal Info:
|
Nlm Unique ID: 0406041 Medline TA: J Comp Neurol Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 393-404 Citation Subset: IM |
Affiliation:
|
Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Axons / ultrastructure* Brain Mapping Carbocyanines / diagnostic use Embryo, Mammalian / cytology Female Gestational Age Neural Pathways / ultrastructure Optic Nerve / ultrastructure Pregnancy Rats Rats, Inbred Strains Retina / cytology* Rhodamines / diagnostic use Superior Colliculi / cytology Vision, Ocular / physiology* |
| Grant Support | |
ID/Acronym/Agency:
|
5T32EY07057-10/EY/NEI NIH HHS; EY07025/EY/NEI NIH HHS |
| Chemical | |
Reg. No./Substance:
|
0/Carbocyanines; 0/Rhodamines; 40957-95-7/3,3'-dioctadecylindocarbocyanine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Direct observations of synapses between GABA-immunoreactive boutons and identified spinocervical tra...
Next Document: Immunohistochemical differentiation of electrophysiologically defined neuronal populations in the re...