Learning and memory in a rat model of social jetlag that also incorporates mealtime

ABSTRACT

Given the increasing role of circadian rhythm disruption in health and disease, animal models are necessary to elucidate the mechanisms and effects involved. Social jetlag is a mild form of chronic circadian rhythm disruption that involves a misalignment between one’s internal time and their external schedule. Using phase advances and delays that are characteristic of a typical working week with sleep binging on the weekend, we propose an animal model of social jetlag. We also investigate the role of the food entrainable oscillator in learning and memory by manipulating the regularity and number of daily meals. We hypothesized that rats exposed to social jetlag would display cognitive impairments. It was unclear if a consistent meal would ameliorate the deleterious effects of social jetlag. Rats exposed to either social jetlag or unpredictable meals had impaired hippocampal-dependent memory. Activity data suggest that the social jetlag paradigm was unentrainable. Our social jetlag paradigm is a useful model of circadian misalignment that impairs cognition by rapidly uncoupling circadian rhythms from the environment.

KEYWORDS:

• Circadian rhythms
• social jetlag
• memory
• hippocampus
• food entrainable oscillator

Acknowledgments

We would like to thank Ian C. Webb for his invaluable help with the circadian rhythm analyses.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by a grant from the Natural Sciences and Engineering Research Council of Canada (NSERC) awarded to CT. SHD is supported by an NSERC postdoctoral fellowship.