Proceedings of The Physiological Society

Sleep Sleep and Circadian Rhythms (London, UK) (2018) Proc Physiol Soc 42, C05

Poster Communications

How is valence encoded during sleep?

A. T. French1, Q. Geissmann1, E. Beckwith1, G. F. Gilestro1

1. South kensington campus, Imperial college london, Wandsworth, United Kingdom.

Sleep, with a few exceptions, is characterised by a state of immobility and reduced awareness of the surrounding environment. While sleep is a fundamental process, it has drawbacks in that a sleeping individual is less likely to detect cues signalling danger, food or mating opportunities which has a direct impact on fitness. While increased arousal thresholds are typical during sleep, some stimuli are more arousing than others. This begs the question: how do certain sensory pathways remain sensitised during sleep and differentially interact with sleep centres? Here we present a new paradigm in order to study arousal in Drosophila (Geissmann et al., 2017). Acetic acid, which is produced by fermenting fruits, was delivered to sleeping flies. Our results show that different concentrations, which signal ripe to rotten fruit, and activate different subsets of olfactory neurons differ in their ability to wake sleeping flies (Semmelhack and Wang 2012). The most arousing concentrations were those with appetitive connotations and were not the most intense. Further we show that valence is an attribute that is highly plastic: both experience and internal state (changes in satiety, sleep pressure and intoxication) can shift arousal thresholds. The mechanisms through which our sensory systems encode valence during sleep remain elusive and the subject represents an exciting yet understudied field.

Where applicable, experiments conform with Society ethical requirements