Visual deprivation fails to reduce calbindin 28kD or GABA immunoreactivity in the rhesus monkey superior colliculus.
ABSTRACT Antibody labeling of the calcium-binding protein calbindin 28kD (CaBP) and gamma-aminobutyric acid (GABA) is altered by short-term monocular deprivation in the lateral geniculate nucleus and visual cortex of adult primates. It is not known whether these alterations occur in other subcortical visual structures. We therefore have examined antibody labeling to CaBP and GABA in the superior colliculus (SC) of visually deprived Rhesus monkeys. One group was monocularly enucleated as adults. The other monkeys experienced different types of monocular and binocular deprivation from birth, including occlusion of one eye, and/or surgically induced aphakia, optically corrected with extended-wear contact lenses, or an intraocular lens implant. Some of these monkeys also had one eye enucleated prior to perfusion. In the SC of normal monkeys, CaBP-immunoreactive neurons formed three laminar tiers within SC, one within the zonal layer (ZL) and upper superficial gray layer (SGL), another bridging the optic and intermediate gray layers, and a third within the deep gray layer. CaBP neurons within the upper tier had small pyriform or stellate morphologies while those in the deeper tiers were slightly larger neurons, most with a stellate morphology. GABA-immunoreactive neurons were densely distributed within the SGL and more sparsely distributed within the deeper layers. These cells were mostly small neurons with horizontal, pyriform, or stellate morphologies. Neither monocular enucleation nor occlusion nor aphakia combined with continuous occlusion of the fellow eye produced any visible reduction in antibody labeling in cells or neuropil within the SC. Full-field measures of labeling intensity (optical density) within the ZL and upper SGL revealed no consistent differences between the SC contralateral or ipsilateral to the affected eye in either CaBP- or GABA-labeled sections. Measures of the optical density, number, and size of labeled neurons also showed no consistent effects of enucleation and/or occlusion. We therefore conclude that the retino-geniculostriate and retino-collicular systems differ in their response to deprivation which is likely due to the significant overlap of retinal axons from the two eyes that occurs in the SC of the Rhesus monkey.
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ABSTRACT: Immunocytochemistry revealed that in the cat dorsal lateral geniculate nucleus (dLGN) almost all parvalbumin-positive cells are GABAergic and about 56% of the calbindin D-28K (calbindin-immunoreactive neurons are also GABA-positive. On the other hand, in the same nucleus, almost all GABAergic neurons contain parvalbumin, and about 89% of the GABA-immunoreactive neurons contain calbindin. Double-labeling with calbindin and parvalbumin revealed that approximately 50% of the immunoreactive neurons are double-stained. In the PGN, virtually all neurons are GABA and parvalbumin-positive. Only a few scattered cells were also calbindin-immunoreactive. These results show that GABAergic geniculate cells can be differentiated on the basis of their calcium-binding protein immunoreactivity. Four types of immunoreactive cells are described here: (1) cells positive for GABA, parvalbumin and calbindin, (2) cells positive for GABA and parvalbumin, but negative for calbindin, (3) cells negative for GABA and parvalbumin, but positive for calbindin, (4) cells negative for GABA, parvalbumin and calbindin.Experimental Brain Research 02/1991; 83(3):513-20. · 2.22 Impact Factor
- Brain Research 10/1976; 114(2):318-27. · 2.88 Impact Factor
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ABSTRACT: The distribution of retinotectal afferents has been studied by autoradiography in 4 adult cats. The findings suggest that crossed and uncrossed retinal fibers terminate in a striking cluster-and-sheet pattern that varies systematically with respect to the retinotopic map of the colliculus. Following unilateral eye injection, labelling was most pronounced in the contralateral colliculus but a suprising volume of label appeared on the ipsilateral side in all cases in the form of dense clumps of silver grains separated by sparsely labelled zones. The contralateral projection appeared densest in the most superficial of the 3 laminae of the stratum griseum superficiale; appreciable labelling was present also in the middle lamina at all survival times used (23-72 h). Near the area centralis representation labelling in both contralateral tiers weakened markedly and local gaps appeared densest in the more dorsal band. Elsewhere, labelling in this dorsal band was generally dense, though sharply interrupted at the optic disc representation and in a curious, elongated lateral zone at mid-collicular levels. In the caudal half of the binocular zone rarefications or 'holes', about 200 mum wide, appeared in the more ventral tier between more densely labelled zones of roughly similar width. On the ipsilateral side, labelling was sparse or absent at the rostral and caudal collicular poles, and was also weak in the region of the area centralis representation save for occasional very superficial grain-clusters. Farther caudally, however, prominent approx. 200 mum wide 'puffs' of label marked the middle lamina of the superficial gray layer. The puffs were most regular in shape in the caudal half of the ipsilateral zone and these were spaced at roughly 200 mum intervals. Puffs lateral to the horizontal meridian representation tended to lie more dorsal than those medial to this line and some of the most lateral puffs at mid-collicular levels invaded the upper lamina of the superficial gray layer. The optic disc representation was marked by a column of label extending through the upper and middle laminae. Similar experiments in cat fetuses suggest that these staggered--and possible even complementary--patterns of crossed and uncrossed retinotectal projection are innate: ipsilateral 'puffs' of labelling and contralateral 'holes' appear in the superior colliculus at least one week before term, as does the ipsilateral filling-in and contralateral gap at the optic disc representation. These observations suggest that in the cat, a vertical as well as horizontal organization may characterize the superficial layers of the superior colliculus. The additional finding of a similar, interrupted puff-like pattern of labelling in the stratum griseum medium following injections in the region of the substantia nigra makes it likely that a somewhat comparable cluster-and-sheet organization may exist also in the deep collicular layers.Brain Research 11/1975; 96(1):1-23. · 2.88 Impact Factor