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Recording and Analysis of Circadian Rhythms in Running-wheel Activity in Rodents
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Normal peripheral circadian phase in the old-old with abnormal circadian behavior
Ai Yamaguchi1, Muneto Tatsumoto2, Ritsuko Matsumura1
1The Research Institute for Time Studies, Yamaguchi University, Yamaguchi, Japan.
Genes to Cells : Devoted to Molecular & Cellular Mechanisms
|August 8, 2018
Summary
Aging and severe dementia may not disrupt the circadian clock pathway. Peripheral clock gene expression rhythms in elderly patients with dementia remained synchronized, suggesting normal input signaling.
Area of Science:
- Chronobiology
- Gerontology
- Neuroscience
Background:
- Circadian rhythms are essential for physiological synchronization.
- Aging is associated with circadian dysfunction, impacting phase, amplitude, and fragmentation.
- Severe dementia in the elderly often presents with abnormal circadian behaviors.
Purpose of the Study:
- To functionally assess the circadian clock machinery in elderly patients with severe dementia.
- To investigate the integrity of the systemic pathway from circadian input to peripheral clocks in this population.
Main Methods:
- Evaluated circadian phase in peripheral clock gene expression rhythms.
- Utilized plucked hair tissues from elderly patients (aged 83-94) with severe dementia and abnormal circadian behaviors.
Main Results:
- Circadian phase in all volunteer patients was unexpectedly within the normal range observed in healthy subjects.
- This indicates that the peripheral circadian clocks maintained their rhythm despite severe dementia and advanced age.
Conclusions:
- The circadian pathway from external environmental inputs to peripheral clocks appears to function normally.
- This finding challenges the assumption of widespread circadian clock machinery failure in the very old with severe dementia.
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