The Horizontal Optokinetic Reflex of the opossum ( Didelphis marsupialis aurita): Physiological and Anatomical Studies in Normal and Early Monoenucleated Specimens

In the opossum the symmetrical binocular horizontal optokinetic nystagmus gives way to an asymmetrical monocular reflex: the nasotemporal (NT) stimulation yielding lower gain than the temporonasal (TN). In adults, monocularly enucleated at postnatal days 21–25 (pnd 21–25), the gain of NT responses i...

Full description

Saved in:
Bibliographic Details
Published in:Vision research (Oxford) 1997-05, Vol.37 (9), p.1207-1216
Main Authors: NASI, J.P, VOLCHAN, E, TECLES, M.T, BERNARDES, R.F, ROCHA-MIRANDA, C.E
Format: Article
Language:English
Subjects:
Animals
Behavioral psychophysiology
Biological and medical sciences
Eye Enucleation
formula omitted
Fundamental and applied biological sciences. Psychology
Monocular enucleation
Neural Pathways
Nucleus of the optic tract
Nystagmus, Optokinetic - physiology
Opossums - physiology
Optokinetic nystagmus
Pattern Recognition, Visual - physiology
Plasticity
Psychology. Psychoanalysis. Psychiatry
Psychology. Psychophysiology
Reflexes
Retina - anatomy & histology
Superior Colliculi - anatomy & histology
Superior Colliculi - physiology
Time Factors
Vision, Monocular
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In the opossum the symmetrical binocular horizontal optokinetic nystagmus gives way to an asymmetrical monocular reflex: the nasotemporal (NT) stimulation yielding lower gain than the temporonasal (TN). In adults, monocularly enucleated at postnatal days 21–25 (pnd 21–25), the gain of NT responses is markedly increased, approaching that of TN. Severe cell loss was detected in the nucleus of the optic tract (NOT) on the deafferented side in early monoenucleated specimens. In normal animals retinal afferents to the NOT are all crossed, while in animals enucleated at pnd 21–25 sparse uncrossed retinal elements were observed. Although this abnormal projection might influence the increase NT response in this subgroup, it is argued that the increased symmetry in monoenucleated opossums may be the result of changes mediated by the commissural connection between both NOTs. © 1997 Elsevier Science Ltd. All rights reserved.
ISSN:0042-6989
1878-5646
DOI:10.1016/S0042-6989(96)00137-X