Johanna (Joke) Meijer is professor and head of the section Neurophysiology, within the department of Cell and Chemical Biology. Her research primarily focuses on unravelling the mechanisms that regulate and synchronise the biological clock, both through external and internal factors. Additionally, she examines the clinical implications of a disrupted biological clock, such as in cancer-related fatigue. She started a national wide program, involving eight Dutch universities to study the effects of clock disturbance on human health and biodiversity. Notably, Meijer is the 2016 recipient of the Aschoff and Honma Prize. In 2019, she received a European Research Council grant.

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Johanna (Joke) Meijer is professor and head of the section Neurophysiology, within the department of Cell and Chemical Biology. Her research primarily focuses on unravelling the mechanisms that regulate and synchronise the biological clock, both through external and internal factors. Additionally, she examines the clinical implications of a disrupted biological clock, such as in cancer-related fatigue. She started a national wide program, involving eight Dutch universities to study the effects of clock disturbance on human health and biodiversity. Notably, Meijer is the 2016 recipient of the Aschoff and Honma Prize. In 2019, she received a European Research Council grant.

Circadian clock

Circadian rhythms have developed as an adaptation to the recurring changes in the environment brought about by the rotation of the earth around her axis. In order to anticipate these changes, innate clocks have evolved in all organisms. Meijer studies the neurophysiological basis underlying clock adaptation to the 24-hour cycle of the environment and to the seasonal cycles in daylength.

She identified the wide range of colors that affect the clock, including UV, and described their effect on the electral activity of clock neurons. She identified the neurotransmitter involved in photoentrainment (glutamate) and the neurotransmitter involved in phase formation between the ventral and dorsal clock regions (GABA). She developed in vivo recordings allowing to investigate the properties of the clock as an integral part of the central nervous system. Her discoveries were awarded with the Aschoff and Honma Prize, the most prestigious recognition in biological rhythm research.

Major Discoveries 

1. Identification of the mechanism for photoperiodic encoding by the central clock
2. Identification of glutamate neurotransmitter for entrainment to the external light-dark cycle and GABA neurotransmitter for entrainment within the central clock
3. Discovery of role for short wavelength photoreceptor in photoentrainment
4. Identification of blue, green, and red light response in the central clock of humans by fMRI
5. Identification of central clock response to physical activity

Academic career

Meijer attended Leiden University in the Netherlands, where she obtained her master’s degree (cum laude) in the Department of Biology, Physics, and Medicine. In 1989, she completed her PhD. in Medical Sciences (cum laude). She obtained a fellowship from the Dutch Royal Academy of Sciences and was appointed full Professor of Neurophysiology in 2007.

Meijer has advanced her research on circadian rhythms and chronobiology as a full Professor and Chair of the Neurophysiology Group at the Leiden University Medical Center in the Netherlands. Additionally, she served as a visiting professor in the Department of Ophthalmology at the University of Oxford in the United Kingdom.

Prizes and honourable appoinments

• 2021: Member of Academia Europaea
• 2020: Dutch National Research Agenda Grant of 10.2 million euros– “BioClock Consortium”.
• 2020: “Ambassador of the Night” Initiative of the Dutch Nature and Environment Federation.
• 2019: European Advanced Research Grant of 2.2 million euros, ERC: “The circadian clock in day-active species: preserving our health in modern society”
• 2016: Aschoff and Honma Prize in Biological Rhythm Research
• 2015: C.U Ariens Kappers Award from the Netherlands Society for the advancement of Sciences, Medicine, and surgery
• 2015: Board member, National Research Agenda (NWO) Complexity cluster; successfully raised 19.5 million euros on Dutch Complexity Research
• 2014–Present: Member of the Royal Dutch Society of Sciences.
• 1999: ‘Best teacher’ award for the period 1994-1999 of the study “BioPharmaceutical Sciences” at Leiden University.
• 1993: “Aschoff’s Rule, a prize for eminent contributions in Chronobiology supporting the interdisciplinary spirit of the field” from Prof. J. Hall (noble prize winner).
• 1989: Fellowship of the Royal Dutch Academy of Sciences.