Mayner L
Department of Behavioural Biology, Australian National University, Canberra.
Brain Behav Evol. 1989;33(6):342-55. doi: 10.1159/000115942.
Very few studies are available on the cyto-architectural features of the thalamus of metatherian mammals. Most of these studies describe the thalamus of a polyprotodont metatherian, the North American opossum, Didelphis virginiana. Studies on diprotodont metatherians are fewer still. There are two descriptions of the thalamus of the Australian possum Trichosurus vulpecula. The only part of the thalamus that has been described in the wallabies is the lateral geniculate nucleus. Hence, there was a need for a description of the thalamus in a wallaby. This study describes the organisation and the cyto-architectonics of the thalamus of the tammar, Macropus eugenii. Except for the midline nuclei, the boundaries of all other nuclei are well demarcated due to their well-differentiated nuclear components. Within the lateral posterior complex, a pulvinar nucleus was identified, and the pre-tectal nuclei show extensive differentiation, as do the medial geniculate nuclei. Also, a small centre-median nucleus was identified. The anteroventral nucleus retains its dorsal position for its entire rostrocaudal extent. The nucleus of the optic tract is located in a dorsal position in the tammar, as it is in cats. The general conclusion from this study is that the nuclear organisation of the thalamus in the tammar, a metatherian mammal, is complex and comparable in most respects to that in cats, eutherian mammals.
关于有袋类哺乳动物丘脑的细胞结构特征的研究非常少。这些研究大多描述的是多门齿有袋类动物——北美负鼠（弗吉尼亚负鼠）的丘脑。对双门齿有袋类动物的研究更少。有两篇关于澳大利亚袋貂（帚尾袋貂）丘脑的描述。在沙袋鼠中，丘脑唯一被描述过的部分是外侧膝状体核。因此，有必要对沙袋鼠的丘脑进行描述。本研究描述了帚尾袋貂丘脑的组织结构和细胞构筑学。除了中线核团外，所有其他核团的边界由于其核成分分化良好而清晰可辨。在外侧后复合体中，确定了一个枕核，前顶盖核表现出广泛的分化，内侧膝状体核也是如此。此外，还确定了一个小的中央中核。腹前核在其整个前后范围内都保持其背侧位置。视束核在帚尾袋貂中位于背侧，就像在猫中一样。这项研究的总体结论是，有袋类哺乳动物帚尾袋貂丘脑的核组织是复杂的，在大多数方面与真兽类哺乳动物猫的丘脑核组织相当。
