Plasticity of circadian rhythmicity during simulated food scarcity and the role of the SCN.

L. de Wit (2015) Plasticity of circadian rhythmicity during simulated food scarcity and the role of the SCN. Master's Thesis / Essay, Biology.

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Abstract

Many aspects of behavior and physiology are subject to circadian rhythmicity, showing predictable patterns on a daily basis that continue even in constant environments. The biological clock has evolved in a way that certain environmental cues can have an impact on the behavioral output of the clock. It was shown that the hypothalamic suprachiasmatic nucleus (SCN) is the main circadian oscillator as in its absence circadian rhythmicity cease to persist while changes in the circadian period of the SCN also change the circadian period of the intact animal. The phase and period of SCN are mainly synchronized to the environment by light input. In addition, other environmental cues called Zeitgebers can also influence the rhythmic output of the circadian system without the involvement of the SCN.1 Examples of these other Zeitgebers are temperature cycles, methamphetamine and food availability. The mechanisms and brain areas involved in these processes are largely unknown. In this paper we aim to find out how the SCN is involved in altering the circadian rhythmicity under simulated food scarcity. Previous research has shown that under the Work-For-Food protocol (WFF) nocturnal mice become day active if they have to work hard to obtain food. This phenotypic plasticity is the focus of our interest and is the underlying motivation for the lesion study. From our data can it can be concluded that SCNx animals do not shift their activity towards the day under a high workload, the SHAM animals do shift their activity towards the day. This means that the SCN is indeed necessary for the phenotypic flexibility shown during simulated food scarcity. The data also shows evidence for a slave oscillator that is expressed in the absence of the SCN under a high workload in complete light.

Item Type:	Thesis (Master's Thesis / Essay)
Degree programme:	Biology
Thesis type:	Master's Thesis / Essay
Language:	English
Date Deposited:	15 Feb 2018 08:09
Last Modified:	15 Feb 2018 08:09
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/13431

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