PhD defense thesis Ni Tang "Circadian and non-visual regulation of light on sleep-wake states in humans and mice"

I'm pleased to invite you to my thesis defense, which will take place on December 16 at 14h in the Bibliothèque DYCOG (Bâtiment 452,opposite CRNL Building). My thesis is entitled “Circadian and non-visual regulation of light on sleep-wake states in humans and mice”.( The presentation will be in English).
 

The jury will be composed of:
Véronique BACH (Reporter), Paul FRANKEN (Reporter), Martine WALLON (Examiner), Victoria REVELL (Examiner) and my thesis supervisors: Claude GRONFIER and Jian-Sheng LIN.

Abstract: Light can affect multiple behavioral and physiological functions, including sleep-wake states, melatonin secretion, pupillary light reflex, metabolism, and mood. Specifically, light coordinates the sleep-wake cycle through a neural circuit that innervates intrinsically photosensitive retinal ganglion cells (ipRGCs) with the circadian pacemaker, the suprachiasmatic nucleus (SCN), which in turn projects to sleep/wake regulatory structures. Light can also affect sleep-wake states in a circadian-independent manner. In humans, light exposure during the night can acutely increase vigilance, while light induces sleep in mice. However, the specific mechanisms of the acute effects of light on sleep are largely unknown. Artificial light at night (ALAN) is ubiquitously used with the development of modern society, and it is inevitable that humans will be exposed to excessive ALAN even during sleep. Whether low-intensity ALAN during sleep affects our sleep and other physiological functions in real life conditions is however still not well documented. Therefore, the objectives of my thesis were to study the mechanisms underlying the acute effects of light on sleep (using mouse models), and to investigate the effects of low ALAN on sleep and physiological functions (in humans). In mouse studies, using several mouse models exposed to specific light protocols, we found that wake-promoting neurons histamine and orexin are required for the sleep-inducing effect of light, and they play a complementary role in this process. In the human study, we found that low-intensity artificial light (20 lux) during sleep disrupted sleep quality, increased body temperature, glucose and decreased heart rate during the night, and affected EEG activity, the sensitivity to light upon awakening.

 

For those unable to attend in person, the defense will also be accessible via Teams.

A buffet will be held at the end of the presentation (all are welcome).

We hope to see you soon,