Ongoing projects – Centre for Study and Treatment of Circadian Rhythms


Circadian oscillation of clock genes in humans and resetting by environment cues

The suprachiasmatic nuclei (SCNs) of the hypothalamus, a specialized region in the brain, generates many circadian rhythms and play the role of master biological clock. This central clock is connected to other regions of the brain and other parts of the body. Certain genes, which are necessary for the function of SCNs cells, are also expressed outside of the central clock.

Thus, secondary or peripheral, clocks exist, in addition to the central clock in the SCNs, in other parts of the body. What could it mean for the gut or the immune system to have a clock? How do central and peripheral clocks interact? The Centre investigates the peripheral circadian clocks that exist in human tissues.

In particular, our studies focus on the effect of night work and glucocorticoid administration on the expression of central and peripheral circadian clocks. We measure the impact of a night shift work schedule on immune function and on the expression of several human genes.

Workers on rotating shift schedules: study of complementary fatigue management approaches

In many cases, shift work implies that the worker must be alert at times of day that are not favorable. The night shift worker, for example, may be required to work when his body would rather sleep.

Certain principles of sleep and circadian physiology, such as the effect of light on the biological clock or strategic planning of naps, can be applied to help shift workers adapt to their schedules. In short, our studies apply principles of sleep hygiene and circadian rhythms to workers on rotating shifts.

Fatigue Risk Management System

In a continuous operation system, several factors, both organizational and individual, contribute to generate physical and mental fatigue among workers. The objective of our studies is to identify the factors that influence the workers fatigue in order to help companies develop scientifically validated fatigue management tools to reduce the risks of fatigue related incidents and accidents at work.

Simulated travel across time zones and treatment by light exposure 

Rapid travels across time zones are often associated with feelings of malaise or maladaptation, particularly in the first days at the new time zone. In the time isolation laboratory, we perform simulated travels across time zones in healthy adults. Our study tests the sensitivity of the circadian system to light exposure as a means to promote the adaptation of circadian rhythms to the destination “time zone”.

Effect of sex on the circadian regulation of sleep and wakefulness

Women are twice as likely as men to suffer from sleep disturbances. Evidence suggests that circadian rhythms and their influence on sleep and vigilance differ between men and women. Our research aims to clarify these differences using sophisticated protocols conducted in temporal isolation.

Effect of the menstrual cycle on the circadian regulation of sleep and wakefulness

Variations in body temperature and sleep patterns occur during the menstrual cycle. The purpose of our studies is to understand how the circadian system participates in these changes and how the menstrual cycle affects circadian rhythms. Our studies focus on healthy women and patients with premenstrual dysphoric disorder.