Projections of the superior colliculus to subdivisions of the inferior pulvinar in New World and Old World monkeys

2000 ◽  
Vol 17 (4) ◽  
pp. 529-549 ◽  
Author(s):  
IWONA STEPNIEWSKA ◽  
HUI-XIN QI ◽  
JON H. KAAS
Keyword(s):  
Substance P ◽  
Superior Colliculus ◽  
New World ◽  
Squirrel Monkeys ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Old World Monkeys ◽  
Area Mt ◽  
Macaque Monkeys ◽  
Visual Area Mt ◽  
Dorsal Lateral Geniculate

Patterns of terminals labeled after WGA-HRP injections in the superior colliculus (SC) in squirrel monkeys and macaque monkeys, and after DiI application in marmosets, were related to the architecture of the pulvinar and dorsal lateral geniculate nucleus (LGN). In all studied species, the SC projects densely to two architectonic subdivisions of the inferior pulvinar, the posterior inferior pulvinar nucleus (PIp) and central medial inferior pulvinar nucleus (PIcm). These projection zones expressed substance P. Thus, sections processed for substance P reveal SC termination zones in the inferior pulvinar. The medial subdivision of the inferior pulvinar, PIm, which is known to project to visual area MT, does not receive a significant collicular input. Injections in MT of a squirrel monkey revealed no overlap between SC terminals and neurons projecting to area MT. Thus, PIm is not the significant relay station of visual input from the SC to MT. The SC also sends an input to the LGN, however, this projection is sparser than the input directed to pulvinar.

Retinal Projections in the Northern Native Cat, Dasyurus-Hallucatus (Marsupialia, Dasyuridae)

1987 ◽  
Vol 35 (2) ◽  
pp. 115 ◽  
Author(s):  
AM Harman ◽  
DP Crewther ◽  
JE Nelson ◽  
SG Crewther
Keyword(s):  
Superior Colliculus ◽  
Lateral Geniculate Nucleus ◽  
Optic Tract ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Accessory Optic System ◽  
Anterograde Transport ◽  
Retinal Projections ◽  
Lateral Geniculate ◽  
Contralateral Eye ◽  
Dorsal Lateral Geniculate

The retinal projections of the northern native cat, Dasyurus hallucatus, were studied by the anterograde transport of tritiated proline and by autoradiography. Seven regions in the brain were found to receive direct retinal projections: (1) the suprachiasmatic nucleus; (2) the dorsal lateral geniculate nucleus; (3) the ventral lateral geniculate nucleus; (4) the lateral posterior nucleus; (5) the nuclei of the accessory optic tract; (6) the pretectal nuclei; (7) the superior colliculus. All nuclei studied received a bilateral retinal projection except the medial terminal nucleus of the accessory optic system, in which only a contralateral input was found. The contralateral eye had a greater input in all cases. As with the related species, Dasyurus viverrinus, there is extensive binocular overlap in the dorsal lateral geniculate nucleus (LGNd). In the LGNd contralateral to the injected eye, the autoradiographs show four contralateral terminal bands occupying most of the nucleus. The axonal terminations in the ipsilateral LGNd are more diffuse but show a faint lamination pattern of four bands. The ventral portion of the LGNd receives only contralateral retinal input, and therefore probably represents the monocular visual field. The other principal termination of the optic nerve, the superior colliculus, has a predominantly contralateral input to both sublayers of the stratum griseum superficiale. However, the ipsilateral fibres terminate only in patches in the more inferior sublayer.

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