The Generation of Binocular Maps in the Hamster Superior Colliculus: Normal and Neonatally Enucleated Animals
In the mammalian retinotectal projection, the existence of direct binocular projections exhibiting congruent binocular receptive fields requires that the nasotemporal axis of the retina displays mapping rules of opposite polarity for the crossed and uncrossed projections. The aberrant ipsilateral retinotectal projection arising after neonatal removal of one eye has been mapped in the hamster to investigate possible strategies for determining the normal differences in mapping polarity. The ipsilateral retinotectal projection in enucleates displays a dual representation which is mirror-symmetric about the representation of the temporal retinal margin. In rostral tectum, temporal retina maps with a polarity appropriate for an uncrossed projection whereas in caudal tectum both temporal and nasal retina are mapped, with a polarity appropriate for a crossed projection. Although two mapping polarities are present in a single projection, neighbour relations are preserved insofar as adjacent points on the tectum receive input from adjacent points on the retina. Possible implications of this mapping will be discussed.
KeywordsReceptive Field Superior Colliculus Mapping Rule Retinal Projection Temporal Retina
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- Cowey, A., and V.H. Perry, 1979, The projection of the temporal retina in rats, studied by retrograde transport of horseradish peroxidase, Exp. Brain Res., 35:45 7–464.Google Scholar
- Keating, M.J., 1974, The role of visual function in the patterning of binocular visual connections, Br. Med. Bull, 30:145–151.Google Scholar
- Kennard, C., 1981, Factors involved in the development of ipsilateral retinothalamic projections in Xenopus laevis, J. Embryol. Exp. Morph, 65:199–217.Google Scholar
- Rhoades, R.W., 1980, Effects of neonatal enucleation on the functional organization of the superior colliculus in the golden hamster, J. Physiol., 301:383–399.Google Scholar
- Rhoades, R.W. and L.M. Chalupa, 1980, Effects of neonatal enucleation on receptive-field properties of visual neurones in the superior colliculus of the golden hamster, J. Neurophysiol., 43:595–611.Google Scholar
- Scholes, J.H., 1981, Retinal fiber projection patterns in the primary visual pathways to the brain. In Laverack, M.S. and D.J. Cosens, Eds. “Sense Organs”, pp. 255–275 (Blackie, Glasgow and London).Google Scholar