2018 Fiscal Year Research-status Report
Direct Optogenetic Investigation of Cortical Excitability and Connectivity in Slow Wave Sleep
| Project/Area Number |
18K06849
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| Research Institution | University of Tsukuba |
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Principal Investigator |
Vogt Kaspar 筑波大学, 国際統合睡眠医科学研究機構, 准教授 (80740034)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | Sleep need / local field potential / cortical afferent |
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| Outline of Annual Research Achievements |
We are able to optogenetically activate cortex at pseudo-random intervals and follow the response during waking, NREM sleep and REM sleep. The behavior of the animal was not affected - in particular wake and sleep times were unchanged between unstimulated control recordings and periods of stimulation. We could measure the fluctuation of sleep need by observing the power of delta (0.5-4 Hz) oscillations in the EEG. Delta oscillations and therefore sleep need were highest (as expected) at the beginning of the 12 h light phase and decreased to a minimum at the beginning of the 12 h dark phase. Cortical response amplitude also varied - roughly in parallel with this natural sleep need oscillation. We then sleep deprived animals for 4 h at the beginning of the light phase (normal sleep time for mice) we saw an increase in delta oscillations after the animals were allowed to sleep, indicating increased sleep need. The cortical response did not show an increase under these circumastances.
In conclusion: Either the daily variation in cortical response size is a consequence of circadian rhythms and not sleep need per se, or sleep deprivation was too stressful and stress interferes with this phenomenon.
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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
The basic experimental technique works and long-term observations of cortical responses are possible. We are able to record local field potentials and single neuron (unit) activity. We have already made a number of novel observations. A manuscript with our first results is in preparation.
At the moment we have to place the light guide for the optogenetic stimulation separate from the recording electrodes. We are currently working on improving this situation.
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| Strategy for Future Research Activity |
We are expanding the sites where ChR2 AAV are injected and are also planning to use different Cre driver mouse lines.
We will soon start experiments to investigate entraining of rhythms using optogenetics
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Research Products
(2 results)
