ATLAS OF DORSAL THALAMUS OF MARSUPIAL BRUSH-TAILED POSSUM, TRICHOSURUS-VULPECULA

  • 1 January 1978
    • journal article
    • research article
    • Vol. 126  (JUN) , 225-245
Abstract
The nuclear configuration in the dorsal thalamus of normal Tasmanian possums is described. Previous studies of Trichosurus and of the American marsupial genus Didelphis are reviewed to standardize thalamic nomenclature within the marsupials and to facilitate comparisons with eutherian mammals. The Trichosurus thalamus displays certain organizational complexities considerably in advance of those seen in Didelphis, particularly with respect to the laminated lateral geniculate nucleus, the cytoarchitectural complexity of the lateroposterior nuclear complex and in the organization of the ventral tier nuclei. In Trichosurus these areas resemble closely the homologous regions in many advanced eutherian mammals. In other features, notably with respect to the complexity and prominence of the midline nuclei and the absence of a median central nucleus, Trichosurus retains a more primitive thalamic configuration, closely resembling that seen in Didelphis. Two thalamic regions not previously described in either Trichosurus or in Didelphis are pictured. One of these, the posteromedial division of the ventroposterior complex, is present in nearly 80% of the animals examined and is missing in the remainder.