Macaque accessory optic system: I. Definition of the medial terminal nucleus

Journal Article · Sat Dec 08 04:00:00 EST 1990 · Journal of Comparative Neurology; (USA)

DOI:https://doi.org/10.1002/cne.903020215· OSTI ID:5941858

Cooper, H M; Baleydier, C; Magnin, M ^[1]

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1. Vision et Motricite, Bron (France)

The organization of the accessory optic system (AOS) has been studied in the macaque monkey following intravitreal injections of tritiated amino acids in one eye. Retinal projections to the dorsal (DTN) and the lateral (LTN) terminal nuclei are identical to those previously described in other primate species. We observed an additional group of retinorecipient cells of the AOS, located between the cerebral peduncle and the substantia nigra, which we define as the interstitial nucleus of the superior fasiculus, medial fibers. In this report, we focus our attention on the medial terminal nucleus (MTN). Although a ventral division of this nucleus (MTNv) was not observed in the macaque, the retina projects to a group of cells in the midbrain reticular formation (MRF), which we argue to be homologous to the dorsal division of the MTN (MTNd). To provide evidence in support of this homology, the retinal projection to the MTNv and MTNd was also examined in 21 additional species from 11 orders of mammals including carnivores, marsupials, lagomorphs, rodents, bats, insectivores, tree shrews, hyraxes, pholidotes, edentates, and five additional species of primates. Whereas the retina projects to both ventral and dorsal divisions in all species studied, in haplorhine primates only the projection to the MTNd is conserved. The relative topological position of the MTNd in the MRF, dorsomedial to the substantia nigra and ventrolateral to the red nucleus, remains constant throughout the mammals. The trajectory of fiber paths innervating the MTNd is also similar in all species. In addition, the MTNd has comparable afferent and efferent connections with retina, pretectum, and vestibular nuclei in all species thus far studied. These results support the unequivocal conclusion that the MTNd is an unvarying feature of the mammalian AOS.

• OSTI ID: 5941858
• Journal Information: Journal of Comparative Neurology; (USA), Journal Name: Journal of Comparative Neurology; (USA) Vol. 302:2; ISSN 0021-9967; ISSN JCNEA
• Country of Publication: United States
• Language: English

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550801* -- Morphology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
BIOLOGICAL VARIABILITY
BODY
BODY AREAS
CARBOXYLIC ACIDS
COMPARATIVE EVALUATIONS
EYES
FACE
GENETIC VARIABILITY
HEAD
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
MAMMALS
MONKEYS
MORPHOLOGY
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PRIMATES
SENSE ORGANS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES