2020 Fiscal Year Research-status Report
Evolution of cerebro-cerebellar system investigated using resting-state functional connectivity in macaque and human
| Project/Area Number |
20K15945
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
アウティオ ヨーナス 国立研究開発法人理化学研究所, 生命機能科学研究センター, 研究員 (40755485)
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| Project Period (FY) |
2020-04-01 – 2024-03-31
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| Keywords | Cerebellum / Cerebro-cerebellar / fMRI / Resting-state / System neuroscience |
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| Outline of Annual Research Achievements |
Cerebellum contain the large majority of the neurons in the brain (80% in humans) and contributes to a wide range of brain functions. However, little is known about the evolution of cerebro-cerebellar system. To corroborate the evolution of primate cerebro-cerebellar system, we have investigated the cerebro-cerebellar communication by capitalizing on recent advances in the resting-state functional magnetic resonance imaging (fMRI) of macaque and human species. We have completed our awake macaque MRI data acquisition and preprocessing pipelines. Specifically, we have found homologous trunk, arm and face somatomotor homonculus, visual and auditory processing cerebro-cerebellar circuits in macaque and human species. These preliminary functional findings in macaques reveal good agreement with early anatomical (Kelly and Strick 2003) and electrophysiological (Snider and Eldred 1952) studies, providing strong validation to our methodological approach. Importantly, the results suggest that only a small fraction of macaque cerebellum is dedicated to a higher-level cognitive functions (<10%) in comparison to humans(>30%). Since total cerebellar surface area estimates in macaque and human are ~60 cm2 and ~590 cm2, respectively (Van Essen), our results suggest that non-somatomotor functions of cerebellar cortex in humans may have expanded over 20-fold. Overall, these observations may provide useful insights regarding cerebellar functions across the primate lineage.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
COVID-19 caused a delay in data acquisition of awake macaque monkeys, data analysis and participation of international conferences. Nonetheless, we have achieved awake resting-state data preprocessing based on preliminary MRI data and publications is currently in preparation for the data acquisition part (Autio et al., in prep). Despite the slight delay, the project is expected to be completed within the funding period.
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| Strategy for Future Research Activity |
Further improvements in group-analysis of both macaque and the young-adult human connectome project data is needed. In particular, the magnetic field inhomogeneties in the cerebellar cortex require careful inspection to achieve robust registration of fMRI to anatomically correct lobules of cerebellar cortex. Test-retest data analysis of cerebro-cerebellar resting-state functional connectivity is currently underway.
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| Causes of Carryover |
Due to COVID-19 there has been a slight delay in experiments and no travel has been possible.
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