The dorsal lateral geniculate nucleus of macropodid marsupials: cytoarchitecture and retinal projections. 1984

K J Sanderson, and J R Haight, and J D Pettigrew

The anatomy of the dorsal lateral geniculate nucleus (LGd) is described in five macropodid species, including two rat kangaroos (bettong and potoroo), two wallabies (pademelon and tammar), and the large grey kangaroo. The distribution of retinal terminals in the LGd was examined following intraocular injections of tritiated amino acids. There are considerable differences in both LGd cytoarchitecture and the patterns of retinal terminations among the five species. Cytoarchitecture in the bettong LGd is relatively simple, displaying a minimal regional differentiation. In contrast, the potoroo LGd is quite complex and displays several well-defined cell laminae, each of which is associated with input from a single eye. Both rat kangaroos display the same basic pattern of retinal termination with three bands of terminals from the contralateral eye and four from the ipsilateral eye. The bands are less sharply defined in the bettong, in which terminals from each eye overlap to a greater extent than is seen in the potoroo. The wallabies and kangaroos display a more complex LGd architecture and patterning of retinal terminal bands. Bilateral retinal projections within the same LGd lamina are unusual in these large macropodids. The number of terminal bands reaches ten in the grey kangaroo--four from the contralateral eye and six from the ipsilateral eye. The pademelon LGd is unusual in that it shows intraspecies variation with some animals displaying five ipsilateral terminal bands and others only four. The results are discussed in comparison with the patterns of LGd organisation observed in other mammalian lines, placental and marsupial. We conclude that LGd lamination and the segregation of retinal inputs to the LGd in marsupials are likely to be the result of evolutionary factors which differ from those which have produced ocular segregation and complex lamination in several lines of placental mammals.

UI MeSH Term Description Entries
D007614 Macropodidae A family of herbivorous leaping MAMMALS of Australia, New Guinea, and adjacent islands. Members include kangaroos, wallabies, quokkas, and wallaroos. Kangaroos,Macropus,Petrogale,Quokkas,Setonix,Wallabies,Wallabies, Rock,Wallaroo,Macropus robustus,Kangaroo,Petrogales,Quokka,Rock Wallabies,Rock Wallaby,Wallaby,Wallaby, Rock,Wallaroos
D008394 Marsupialia An infraclass of MAMMALS, also called Metatheria, where the young are born at an early stage of development and continue to develop in a pouch (marsupium). In contrast to Eutheria (placentals), marsupials have an incomplete PLACENTA. Metatheria,Marsupials,Marsupial
D009474 Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM. Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D012160 Retina The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent. Ora Serrata
D005075 Biological Evolution The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics. Evolution, Biological
D005829 Geniculate Bodies Part of the DIENCEPHALON inferior to the caudal end of the dorsal THALAMUS. Includes the lateral geniculate body which relays visual impulses from the OPTIC TRACT to the calcarine cortex, and the medial geniculate body which relays auditory impulses from the lateral lemniscus to the AUDITORY CORTEX. Lateral Geniculate Body,Medial Geniculate Body,Metathalamus,Corpus Geniculatum Mediale,Geniculate Nucleus,Lateral Geniculate Nucleus,Medial Geniculate Complex,Medial Geniculate Nucleus,Nucleus Geniculatus Lateralis Dorsalis,Nucleus Geniculatus Lateralis Pars Dorsalis,Bodies, Geniculate,Complex, Medial Geniculate,Complices, Medial Geniculate,Corpus Geniculatum Mediales,Geniculate Bodies, Lateral,Geniculate Bodies, Medial,Geniculate Body,Geniculate Body, Lateral,Geniculate Body, Medial,Geniculate Complex, Medial,Geniculate Complices, Medial,Geniculate Nucleus, Lateral,Geniculate Nucleus, Medial,Geniculatum Mediale, Corpus,Geniculatum Mediales, Corpus,Lateral Geniculate Bodies,Medial Geniculate Bodies,Medial Geniculate Complices,Mediale, Corpus Geniculatum,Mediales, Corpus Geniculatum,Nucleus, Geniculate,Nucleus, Lateral Geniculate,Nucleus, Medial Geniculate
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D013045 Species Specificity The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species. Species Specificities,Specificities, Species,Specificity, Species
D014795 Visual Pathways Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract. Pathway, Visual,Pathways, Visual,Visual Pathway

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