2018 Fiscal Year Research-status Report
Large brain evolution in cetaceans
| Project/Area Number |
18K14833
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| Research Institution | Hokkaido University |
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Principal Investigator |
PATZKE NINA 北海道大学, 高等教育推進機構, 助教 (20801690)
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| Project Period (FY) |
2018-04-01 – 2020-03-31
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| Keywords | Brain / Evolution / comparative neuroanatomy / Isotropic fractionator / MRI / Morphology / Cetaceans / Odontocete |
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| Outline of Annual Research Achievements |
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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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Until now we did not encounter any big difficulties in the project. Although the brains of the whales are rather large 5 kg, we are progressing well in time.
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| Strategy for Future Research Activity |
In first half this fiscal year, we are going to finish the cell counting of the beaked whale and the connectivity of the whales and ungulates using the DTI data. We will also start with comparative histological analysis of the cortex and compare it with the results of the connectivity analysis.
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| Causes of Carryover |
This funding will be used to cover extra required MRI and DTI scanning cost. MRI and DTI scanning fee is 40.00o per 5h time slot. In total 4.7 slots will be paid for.
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[Presentation] 磁気共鳴映像法(MRI)を用いたツチクジラ脳の形態と容積測定2018
Author(s)
Nina Patzke, Isabel Fernandez, Jinta Kasai, Asa Watanabe, Khin Khin Tha, Kazuhiro Wada, Toshiya Matsushima , Mari Kobayashi , Bruno Mota
Organizer
Anual Meeting of the Japanese Cetology Society
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