Circadian rhythmicity is a fundamental feature of biological organization and is deeply rooted in the biology of all living organisms. These rhythms have developed as an adaptation to the recurring changes in the environment brought about by the rotation of the Earth around its axis and the orbit of the Earth around the Sun. In order to anticipate these changes, innate clocks have evolved that allow organisms to prepare for the predictable onset of night and day. Our circadian system evolved as a robust mechanism to increase fitness. However, in modern society, the widespread use of artificial light and electronic devices has drastically—and rather suddenly—changed the photic environment in which we live, and compelling studies now demonstrate that a lack of a proper light-dark cycle is detrimental to human health. Recent data from our group and others showed that deviating from the natural cycles of light and dark can have severe effects on clock function. Reduced function of the central clock causes key organ systems to lose their synchrony and/or 24-hour pattern, increasing the risk of developing a wide range of severe health conditions, including diabetes, neurological and cardiovascular disease, immune dysfunction, cancer, sleep disorders, and depression. With our modern society’s 24-hour economy and our increasing use of artificial light, perturbations in our clock function are likely to continue to increase, underscoring the importance of developing strategies to strengthen clock function.
Topics of the Meijer group
- Neuronal network organization of the circadian clock in day active vs night active animals
- Light responses of the circadian system (retinal photopigments, jet lag, shift work)
- Clinical: aging, sleep, metabolic syndrome, depression, cancer
- Sleep and exercise: non-photic effects on the SCN clock
- Complexity theory; emergent properties of hierarchical neuronal networks
- Chronopharmacology: strategies for enhancing clock function, optimizing drug timing
- Field research, ecology, biodiversity, population dynamics, nocturnal light pollution
For students with a possible career in science
- Interview with Joke Meijer: How do you know you want to become a scientist?
Corona Disease Related
- April 2020: Meijer & Oude Vrielink (2020): Using surgical wrapping material for the fabrication of respirator masks. PLOS ONE.
As a community outreach project, this paper has been shortened and made available in over 15 languages.
It is freely obtainable through a dedicated website: https://coronamedicalmasks.org/
- Congress of European Sleep Research Society. ‘An ancient clock facing modern times’
24 oktober 2020
Recent prizes and awards
- 2019: ERC Advanced Grant: “The circadian clock in day-active species: preserving our health in modern society”
- 2016: Aschoff and Honma Prize in Biological Rhythm Research (International Selection Committee, chaired by Dr. Takao Kondo)
- Olde Engberink, A.H.O., Huisman,J., Michel,S., Meijer, J.H. (2020) Brief light exposure at dawn and dusk can encode day‐length in the neuronal network of the mammalian circadian pacemaker. FASEB 34(10) 13685-13695
Current special positions/functions of JH Meijer
- 2020: “Ambassador of the Night” (Natuur en Milieufederatie Nederland).
- Visiting Professor Oxford University
- Member of the Royal Holland Society of Sciences and Humanities
- Member of the Life Sciences Board, Lorentz Center, Leiden
- National board of Complexity research (Grip on Complexity)
- January 2020: Diligentia lezing “De Biologische Klok in de Moderne Samenleving”, Den Haag.
- 22 november 2019: Cleveringa lezing, Parijs.
- 26 oktober 2019: Lezing tijdens de Nacht van de Nacht in Artis. Titel: Waarom is het donker zo belangrijk voor de mens? More information (in Dutch).
- 2016: Priceless: The Value Proposition for the Humanities – Annual Winter Lecture at the Royal Holland Society of Sciences and Humanities (KHMW) by prof. G.D. Block, Chancellor and Distinguished Professor of Psychiatry and Biobehavioral Science at UCLA, USA (Main organizer: prof. J.H. Meijer)