Finding an assay that reveals effects of sleep deprivation on decision making in Drosophila
File(s)
Author(s)
Bicazan, Eugenia-Diana
Type
Thesis
Abstract
This study makes use of cutting-edge technology to tackle the intricate links between decision making and
sleep in the Drosophila Melanogaster fly using various innovative behavioural paradigms.
The assays developed are iteratively improved to be suitable for high-throughput experiments and automatic video tracking of desired features. The final paradigm presents the fly with the simple decision
of passing through two holes of different sizes: a large hole through which it can pass easily and a smaller
one through which it can pass with some difficulty. Independently of the external conditions such as light,
shape of the assay and time of the day or of the internal states such as genetic background and sleep state,
all the flies choose to make multiple passages through both holes and unanimously show a preference for
the bigger hole. Our paradigm is unique in that it allow us to assess flies decisions independently of the
locomotion state by evaluating the proportion of passages through the two holes. Remarkably, this parameter is conserved in the same genetic background. Moreover, our results confirm and strengthen previous
studies showing that locomotion is increased by space restriction in males.
When faced with our non-conventional paradigms, after prolonged sleep deprivation, flies suppress
their sleep rebound. In addition, they show no behavioural differences to control flies. It appears that
the sleep pressure built up through homeostatic regulation is not important enough to counteract the in-
creased arousal state resulted from space restriction in order to trigger sleep. However, when experiments
are performed in the afternoon during flies ”siesta”, they fall asleep, indicating that the sleep pressure arising from circadian regulation is more significant than the sleep pressure coming from homeostatic regulation.
sleep in the Drosophila Melanogaster fly using various innovative behavioural paradigms.
The assays developed are iteratively improved to be suitable for high-throughput experiments and automatic video tracking of desired features. The final paradigm presents the fly with the simple decision
of passing through two holes of different sizes: a large hole through which it can pass easily and a smaller
one through which it can pass with some difficulty. Independently of the external conditions such as light,
shape of the assay and time of the day or of the internal states such as genetic background and sleep state,
all the flies choose to make multiple passages through both holes and unanimously show a preference for
the bigger hole. Our paradigm is unique in that it allow us to assess flies decisions independently of the
locomotion state by evaluating the proportion of passages through the two holes. Remarkably, this parameter is conserved in the same genetic background. Moreover, our results confirm and strengthen previous
studies showing that locomotion is increased by space restriction in males.
When faced with our non-conventional paradigms, after prolonged sleep deprivation, flies suppress
their sleep rebound. In addition, they show no behavioural differences to control flies. It appears that
the sleep pressure built up through homeostatic regulation is not important enough to counteract the in-
creased arousal state resulted from space restriction in order to trigger sleep. However, when experiments
are performed in the afternoon during flies ”siesta”, they fall asleep, indicating that the sleep pressure arising from circadian regulation is more significant than the sleep pressure coming from homeostatic regulation.
Version
Open Access
Date Issued
2019-03
Date Awarded
2020-03
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Faisal, Aldo
Gilestro, Giorgio
Sponsor
Biotechnology and Biological Sciences Research Council (Great Britain)
Publisher Department
Bioengineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)