| 研究実績の概要 |
1.Specimen acquisition: Until now, we collected brains from three Baird’s beaked whales and two brains of harbor porpoises. In addition, one brain from one sika deer and two domestic cows were collected.
2.MRI and DTI analysis: All brains collected were suspected to MRI scans. The MRI scans of the Beaked whale were analyzed for morphology and volumetric. The external and internal anatomical organization revealed typical characteristics, which were previously observed in other Odontoceti: (1) considerable encephalization; (3) the typical odontocete neocortical gyrification pattern; (4) lack of olfactory bulb and tract; (5) large cerebellum; (6) thin cortical grey matter; (7) thin corpus callosum; (8) very large basal ganglia. In addition, we measured the cortical area external perimeter of a sequence of coronal MR images and used those to calculate the volume and the exposed surface area of the entire cortical hemisphere. The cortical volume and exposed surface reveal the same scaling relationship as that of a multi-species data set previous reported. This finding indicates that overall external shape of the 2 cetaceans is typical mammalian, despite its unusual detailed shape, large size and high gyrification level. The DTI scan were obtained from the Baird’s beaked whales and harbor porpoises and the analysis is under progress.
3.Cell counting: Using the isotropic fractionator technique we finished the counting of the neurons and glial cells in the harbor porpoise and the data is being analyzed. The cell counting of the Beaked whale is under progress.
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