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Titolo:
ORGANIZATION OF RETINAL GANGLION-CELL AXONS IN THE OPTIC FIBER LAYER AND NERVE OF FETAL FERRETS
Autore:
FITZGIBBON T; REESE BE;
Indirizzi:
UNIV SYDNEY,DEPT CLIN OPHTHALMOL C09 SYDNEY NSW 2006 AUSTRALIA UNIV CALIF SANTA BARBARA,NEUROSCI RES INST SANTA BARBARA CA 93106 UNIV CALIF SANTA BARBARA,DEPT PSYCHOL SANTA BARBARA CA 93106
Titolo Testata:
Visual neuroscience
fascicolo: 5, volume: 13, anno: 1996,
pagine: 847 - 861
SICI:
0952-5238(1996)13:5<847:OORGAI>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
RETINOGENICULATE PROJECTION FIBERS; ADULT GOLDFISH EYE; RETINOTOPIC ORGANIZATION; RETINOTECTAL PROJECTION; SUPERIOR COLLICULUS; JUVENILE GOLDFISH; CHIASMATIC REGION; UNCROSSED AXONS; ALBINO FERRETS; CHICK RETINA;
Keywords:
RETINOTOPY; CHRONOTOPY; OPTIC NERVE HEAD; OPTIC CHIASM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
74
Recensione:
Indirizzi per estratti:
Citazione:
T. Fitzgibbon e B.E. Reese, "ORGANIZATION OF RETINAL GANGLION-CELL AXONS IN THE OPTIC FIBER LAYER AND NERVE OF FETAL FERRETS", Visual neuroscience, 13(5), 1996, pp. 847-861

Abstract

Previous authors have hypothesized that retinotopic projections may be influenced by 'preordering' of the axons as they grow towards their targets. In some nonmammalian species, axons are reorganized at or near the optic nerve head to establish a retinotopic order. Data are ambiguous concerning the retinotopy of the mammalian retinal nerve fiber layer and whether fibers become reorganized at the optic nerve head. Wehave examined this question in fetal and newborn ferrets (Mustela putorius furo) by comparing the arrangement of axons in the retinal nervefiber layer with that in the optic nerve. DiI or DiA crystals were implanted into fixed tissue in the innermost layers of the retinal periphery, or at a location midway between the periphery and the optic nerve head. Fluorescence labelling was examined in 100-200 mu m Vibratome sections, or the eyecup and nerve were photooxidized and 1-2 mu m longitudinal or transverse sections were examined. Regardless of fetal age, eccentricity or quadrant of the implant site, a segregation of labelled peripheral axons from unlabelled central ones was not detected within the nerve fiber layer. Axons coursed into the nerve head along themargin of their retinal quadrant of origin, often entering the optic nerve as a radial wedge, thus preserving a rough map of retinal circumference. However, peripheral axons were in no way restricted to the peripheral (nor central) portions of the nerve head or nerve, indicatingthat the optic axons do not establish a map of retinal eccentricity. Our results demonstrate that (1) the nerve fiber layer is retinotopic only with respect to circumferential position and (2) optic axons are not actively reorganized to establish a retinotopic ordering at the nerve head. The present results suggest that any degree of order presentwithin the optic nerve is a passive consequence of combining the fascicles of the retinal nerve fiber layer; optic axons are not instructedto establish, nor constrained to maintain, a retinotopic order withinthe optic nerve.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 06/07/20 alle ore 08:53:57