Circadian misalignment has harmful effects on the brain behaviour

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Deibel, Scott
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Lethbridge, Alta. : University of Lethbridge, Dept. of Neuroscience
With circadian rhythm disruption being a huge component of modern life, it is paramount to understand how it affects the brain and body. Circadian rhythm disruption impairs memory in humans and rodents. We use phase advances of the light dark cycle to challenge circadian rhythms in rats and observe concomitant memory impairments. While this has been extensively documented, it is unclear exactly how it occurs. The goals of this thesis were threefold: 1) Determine if our phase-shifting paradigm induces circadian misalignment. 2) Determine if the effects of our paradigm are long lasting. 3) Investigate three of the most theorized mechanisms for how circadian rhythm disruption elicits memory impairments. I found that our paradigm induces circadian misalignment that has long lasting effects on activity rhythms and memory. I also determined that sleep deprivation, elevated corticosterone, and hippocampal cell death are not responsible for the memory impairment induced by circadian rhythm disruption.
Circadian rhythms